Canadian Society Société Canadienne

of Plant Physiologists de Physiologie Végétale

Annual Meeting 2008 Assemblée Annuelle

th

ième

Ottawa 14-17.06.2008

Schedule

and

Abstracts

Calendrier

et

Résumés

In Commemoration of the CSPP’s Golden AnniversaryEn l’honneur du 50ième anniversaire de la SCPV

CSPP-2008 Program

Programme SCPV-2008

Annual Meeting 2008 Assemblée Annuelle

Ottawa

14-17.06-2008

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Table of contents – Table des matières

Welcome – Bienvenue 3 Acknowledgements – Remerciements 4 General information – Informations générales 6 Map of venues – Carte du site 6 Poster and exhibit hours – Horaire des affiches et des exposants 8 General and executive meetings – Réunions générale et de l’exécutif 8 Scientific tours – Visites scientifiques 8 Meals – Repas 9 Daily schedule – Calendrier des événements 10 Saturday, June 14 – Samedi 14 juin 11 Sunday, June 15 – Dimanche 15 juin 12 Monday, June 16 – Lundi 16 juin 15 Tuesday, June 17 – Mardi 17 juin 19 Abstracts – Résumés 23 Gold Medal Address – Mot du Médaillé d’Or 23 Plenary lectures – Séances plénières 23 Concurrent sessions – Séances parallèles 29 Posters – Affiches 40 Index 85 List of participants – Liste des participant/e/s 86 Notes 93

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Welcome – Bienvenue

Welcome to CSPP 2008!

This year, 2008, marks the 50th anniversary of

the Canadian Society of Plant Physiologists. Our

theme is to honour our pioneers and to see how

plant physiology will address the problems of the

future. Constance Nozzolillo will provide a

history of the Society. Our Gold medalist,

Anthony Glass, will review the science of nutrient

uptake and its future. This year’s plenary sessions

deal with current and future issues such as

biofuels, bioremediation, natural health products,

and plants in space. The 50th anniversary

lecture by David Bergvinson will provide insight

into the role of science in world food crisis. A tour

of Canada’s historic agriculture research station

at the Central Experimental Farm will close our

conference.

It is our wish that this meeting will be enjoyable

and a scientific milestone for those in the field.

Bienvenue à la SCPV 2008!

L’année 2008 marque le 50ème anniversaire de

la Société canadienne de physiologie végétale.

Notre thème se veut d’honorer nos pionnières et

nos pionniers et d’envisager comment la

physiologie végétale contribuera dans la résolution

des problèmes du futur. Constance Nozzolillo

relatera l’histoire de la Société. Notre médaillé

d’Or, Anthony Glass, revisitera la science de

l’absorption minérale et son futur. Cette année,

les sessions plénières portent sur les

problématiques actuelles et futures telles que les

biocarburants, la bioremédiation, les

nutraceutiques naturels et les plantes dans

l’espace. La conférence du 50ème anniversaire

par David Bergvinson s’intéressera au rôle de la

science dans la crise alimentaire mondiale. Une

visite de la station historique de la recherche en

agriculture du Canada à la Ferme expérimentale

centrale clôturera notre rencontre.

En espérant que cette rencontre soit des plus

agréable et que ce soit un événement scientifique

des plus enrichissant pour toutes et tous.

Co-chairs CSPP 2008 – Co-présidents SCPV 2008

John T Arnason Brian Miki University of Ottawa Université d’Ottawa

Agriculture & AgriFood Canada Agriculture et agro-alimentaire Canada

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Acknowledgments – Remerciements

2008 Executive committee – Comité exécutif 2008 President – Président Vice-president – Vice-président Peter Pauls (U Guelph) Carl Douglas (U British Columbia) Secretary – Secrétaire Treasurer – Trésorier Line Lapointe (U Laval) Harold G Weger (U Regina) Western region director – Directeur de la région de l’ouest Eastern region director – Directeur de la région de l’est Soheil S Mahmoud (U British Columbia) Malcolm Cambell (U Toronto) Communications director Directeur des communication Bulletin Editor – Rédacteur du bulletin

Education director – Directeur de l’éducation

Gordon Gray (U Saskatchewan) Greg Moorhead (U Calgary) Science policy director – Directrice de la politique des sciences

Senior director – Directrice senior

Barbara Moffatt (U Waterloo) Priti Krishna (U Western Ontario) Student & PDF Representative – Représentante des étudiant/e/s et des collègues post-doctorant/e/s Alexandra Reid (AAFC-AAC)

2008 Conference organizing committee – Comité organisateur du congrès 2008 Co-chairs – Co-présidents Members – Membres John T Arnason (U Ottawa) Susan Aitken (Carleton U) Brian Miki (AAFC-AAC) Christiane Charest (U Ottawa) Douglas A Johnson (U Ottawa) Leo Savitch (AAFC-AAC) Tim Xing (Carleton U)

Supporters – Commanditaires University of Ottawa – Université d’Ottawa Carleton University Canadian Food Inspection Agency Natural Resources Canada Agence canadienne d’inspection des aliments Ressources naturelles Canada Plant Biotechnology Institute NRC – Institut de biotechnologies des plantes CNRC

Monsanto Canada Inc Pioneer Hi-Bred Limited Biochambers Inc

Exhibitors – Exposants NRC Press – Presses scientifiques du CNRC Qubit Systems Inc Nikon Canada Inc Regent Instruments Inc Hoskin Scientific Canadian Food Inspection Agency Agence canadienne d’inspection des aliments

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Registration packages – Trousses de la conférence Rideau Centre Centre Rideau

Coupon book Livret de coupons-rabais

Tourism Ottawa Activity book

Tourisme Ottawa Livret d’ activités

Central Experimental Farm Ferme Expérimentale Centrale

Activity book Livret d’ activités

Prizes – Prix

Agrisera Fisher Scientific

French translation – Traduction française

Christiane Charest (U Ottawa)

Website design & maintenance – Design et mises à jour du site web Benoit Whissel (AAFC-AAC)

Management of registrations & databases – Gestion des inscriptions et des bases de données Hélène Labbé (AAFC-AAC)

Design of logo, t-shirt & conference book – Design du logo , du gaminet et du programme Patrick Audet (U Ottawa)

Abstract compilation – Compilation des résumés

Mathieu Fortin (U Ottawa)

Volunteer student hosts – Étudiantes et étudiants bénévoles University of Ottawa – Université d’Ottawa

Carleton University

Fida Ahmed Charlotte McDonald Reem Alhattab Kristina Sabou Patrick Audet Kristina McIntyre Adel Al-Shammari Colleen Woodhouse Fayçal Benothmane Carolina Ogrodowczyk Chad Conroy Xuejing Xing Shuyou Han Jaimie Schnell Huang Huang Cory Harris Cathy Sun Justin Kicks Vicky Fillion Chieu Anh Ta Nik Kovinich Mathieu Fortin Tarek Tbaileh Jen Pearce

Cover photos – Photos en couverture Top-left Haut-gauche

Flower & bud of Hieracium pratense (R Larry Peterson)

Bottom-left Bas-gauche

Arabidopsis thaliana flower (Shelley Hepworth)

Top-center Haut-centre

Transverse section of Abutilon menziesii root (R Larry Peterson)

Bottom-center Bas-centre

Longitudinal root showing arbuscular mycorrhizal hyphae (R Larry Peterson)

Top-right Haut-droite

CGS spatial development of Arabidopsis thaliana leaf vasculature (Anne-Gaëlle Rolland-Lagan)

Bottom-right Bas-gauche

CGS protein tetramer (Susan Aitken)

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General information – Informations générales

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Poster & exhibit hours – Horaires des affiches et des exposants Participants may set-up their posters in the chapel of Tabaret hall as of 1pm on Sunday 15 June. The main Poster Session will take place that evening from 4:40pm to 7pm. Subsequently, open viewing will be available until 5pm Monday 15 June at which time all posters must be removed. Exhibitors’ booths will be available over the entire duration of the conference in the basement lobby of Marion hall. Les participant/e/s peuvent installer leurs affiches à la chapelle du pavillon Tabaret à partir de 13h le dimanche 15 juin. La session principales des affiches aura lieu le soir même de 16h40 à 19h. Subséquemment, les visites seront possibles jusqu'à 17h le lendemain, le lundi 16 juin, moment auquel toutes les affiches devront être enlevées. Les kiosques des exposants seront disponibles tout au long du congrès dans le sous-sol du pavillon Marion.

General and executive meetings – Réunions générale et de l’exécutif All meetings will take place in CAREG 107 with exception to the Annual Business Meeting which will be held at Marion hall in a room to be determined. Toutes les réunions auront lieu dans la pièce 107 du pavillon CRAGE, à l’exception de la Rencontre Générale Annuelle qui se déroulera au pavillon Marion (pièce à déterminer).

Scientific tours – Visites scientifiques The scientific tours of the Eastern Cereal and Oilseed Research Centre and the Central Experimental Farm and of the University of Ottawa Teaching Laboratory Facilities will take place at 1:30pm on Tuesday 17 June. Please consult the daily schedule for a description of these tours (p.20-21). Les visites scientifiques du Centre de recherche de l’est sur les céréales et oléagineuses de la Ferme expérimentale centrale et des Laboratoires d’Enseignement de l’Université d’Ottawa se dérouleront a 13h30, le mardi 17 juin. Veuillez consulter le calendrier d’événements pour de plus amples informations (p.20-21).

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Meals and special events – Repas et évènements spéciaux Lunches will be taken at the University Center (UCU) cafeteria whereas coffee breaks will be held at the various presentation halls and meeting rooms. Please consult the program and campus map for their specific times and locations. Lunches and coffee breaks are all included in the registration fees. Les déjeuners seront pris à la cafétéria du Centre Universitaire ( UCU), alors que les pauses café se dérouleront dans les différents pavillons où ont lieu les présentations ou dans les salles de réunions. Veuillez consulter le programme et la carte du campus pour plus de précision sur les horaires et les emplacements. Tous les déjeuners et pauses café sont inclus dans les frais d’inscription. Saturday, June 14 – Samedi 14 juin 17-21h BBQ reception – Réception ‘Sur le gril’ (cour UCU court) Included in the registration fees – Incluse dans les frais d’inscription Sunday, June 15 – Dimanche 15 juin 16h40 Poster session and mixer – Séance d’affiches et cocktail (chapelle Tabaret chapel) A cash bar and appetizers will be available during the poster session Un bar payant et des amuse-gueules seront disponibles pendant la session d’affiches Monday, June 16 – Lundi 16 juin 19h Banquet (‘The Roof Top Terrace’, National Art Centre, 53 Elgin St) Banquet (‘The Roof Top Terrace’, Centrer National des Arts, 53, rue Elgin) The conference banquet will include ceremonies and addresses from the recipients of the CSPP awards. (Tickets sold separately will be asked) Des cérémonies et des présentations des Prix aux récipiendaires de la SCPV se dérouleront pendant le banquet. (Les billets vendus séparément seront exigés)

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Daily schedule – Calendrier des événements

Saturday, June 14 Samedi 14 juin

Sunday, June 15 Dimanche 15 juin

Monday, June 16 Lundi 16 juin

Tuesday, June 17 Mardi 16 juin

8h Registration Inscription

Registration Inscription

Registration Inscription

8h – 10h

Welcome address / Bioenergy & biofuels

Mot de bienvenue /

Bioénergie & biocarburants

Plant development

Développement des plantes

Communication with micro-

organisms

Communication avec des micro-organismes

10h Coffee break Pause café

Coffee break Pause café

Coffee break Pause café

10h30 – 12h

Plant natural health products

Produits naturels des plantes

Cellular communication

Communication cellulaire

Plants in new environments /

CSPP 50th Anniversary Lecture

Plantes dans de nouveaux

environnements / Conférence du 50e

anniversaire de la SCPV

12h – 13h30 Lunch

Déjeuner Lunch

Déjeuner Lunch

Déjeuner

13h30 – 15h

Carbon & nitrogen metabolism / Biotic Stress

Métabolisme du carbone et de l’azote / Stress biotique

Trace elements &

phytoremediation / Teaching & education / Employment &

training

Microéléments et phytoremédiation /

Enseignement & éducation / Emploi & formation

15h – 15h30 Coffee break Pause café

Coffee break Pause café

15h30 – 17h

Photosynthesis / Plant development

Photosynthèse / Développement des plantes

Abiotic stress / Secondary

metabolism & biotechnological applications

Stress abiotique /

Métabolisme secondaire & applications

biotechnologiques

Scientific tours

Visites scientifiques

17h – 21h

Registration and BBQ

reception

Inscription et réception ‘Sur le gril’

Poster session & Mixer

Séance d’affiches & Cocktail

Banquet: Awards and Gold

Medal address

Banquet : Remise des prix et Mot du Médaillé d’Or

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Saturday, June 14 – Samedi 14 juin

17h-21h Registration – Inscription (cour UCU court yard) 18h-21h BBQ reception – Réception ‘Sur le gril’ (cour UCU court yard)

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Sunday, June 15 – Dimanche 15 juin

8h Registration – Inscription (pavillon Marion hall)

10h Coffee break – Pause café (foyer CAREG-CRAGE & Marion lobby)

Plenary Session 1 – Séance plénière 1 (pavillon Marion hall) Chair – Responsable : Connie Nozzolillo, U Ottawa

Bioenergy and biofuels – Bioénergie et biocarburants 8h30 A1-2 Sustainable bioeconomy systems:

A critical role for the plant sciences David Layzell, Queen’s U

9h10 A1-3 Lignin modification for improvement of dedicated bioenergy crops Richard Dixon, Noble Foundation 9h50 Oaks Scholarship Announcement Pierre Bilodeau, NSERC-CRSNG

Opening Ceremony – Cérémonie d’ouverture (pavillon Marion hall) 8h Introduction André E Lalonde, Dean of Faculty of Science – Doyen de la Faculté des sciences 8h10 Welcome address – Mot de bienvenue Peter Pauls, CSPP President – Président SCPV 8h15 A1-1 The ‘geneology’ of the science of plant physiology in Canada

Connie Nozzolillo, U Ottawa

Plenary Session 2 – Séance plénière 2 (pavillon Marion hall) Chair – Responsable : Christiane Charest, U Ottawa

Plant natural health products – Produits naturels des plantes 10h30 A2-4 Plant natural products and society:

The science challenges from bioenergy to medicinals Norman Lewis, Washington State U

11h10 A2-5 Opening Pandora’s box: Genes and alkaloids galore – Now what?

Peter Facchini, U Calgary 11h35 A2-6 Integrative therapeutic trait selection for bioproduct crop plant improvement Shannon Cowan, U British Columbia

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12h Lunch – Déjeuner (cafétéria UCU cafeteria) Meeting of the out-going executive – Réunion du comité exécutif sortant (CRAGE 107 CAREG)

14h50 Coffee break – Pause café (foyer MacDonald & Marion lobby)

Concurrent session 1 – Séance parallèle 1 (pavillon Marion hall) Chair – Responsable : Bill Plaxton, Queen’s U

Carbon and nitrogen metabolism – Métabolisme du carbone et de l’azote 13h30 C1-1 Functional characterization of a sucrose transporter

in winter wheat (Triticum aestivum cv. McClintock) Chelsey McDougall, U Manitoba 13h50 C1-2 Daphnetin is a potential modulator of phosphoribulokinase

during cold acclimation of wheat Khalil Kane, UQAM

14h10 C1-3 The effect of nitrogen concentration on compatible solutes during salinity stress in Thellungiella salsuginea Ashley Tattersall, McMaster U 14h30 C1-4 Molecular regulatory properties of novel mono-ubiquitinated

PEPC heterotetramer from germinated castor oil seeds William C Plaxton, Queen’s U

Concurrent session 2 – Séance parallèle 2 (pavillon MacDonald hall) Chair – Responsable : Alan Good, U Alberta

Biotic stress – Stress biotique 13h30 C2-5 Inducible expression of antimicrobial peptides as an approach

to enhance plant resistance to a variety of phytopathegens Dmytro P Yevtushenko, U Victoria

13h50 C2-6 Molecular biochem configer defense against insects: Formation of (+)-3-carene in Sitka spruce attack by white pine weevil Dawn Hall, U. British Columbia 14h10 C2-7 The role of the Arabidopsis cyclic nucleotide-gated ion channels, AtCNGC11 and 12 in abiotic and biotic stress responses Keiko Yoshioka, U Toronto 14h30 C2-8 Compilation of a database of RNA profiles comparing susceptible and resistant wheat infected with Fusarium graminearum Thérèse Ouellet, AAFC-AAC

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Concurrent session 3 – Séance parallèle 3 (pavillon Marion hall) Chair – Responsable : Norman PA Huner, U Western Ontario

Photosynthesis - Photosynthèse 15h20 C3-9 LHCSR is an ancient member of the light harvesting complex superfamily and it is required for photoprotection in Chlamydomonas reinhardtii Graham Peers, U California Berkeley 15h40 C3-10 Characterization of a high non-photochemical quenching mutant of Chlamydomonas reinhardtii Lyndsay L Gray, U Saskatchewan 16h C3-11 Structure-function analysis of the Arabidopsis Toc159 family acidic domains Matthew D Smith, Wilfred Laurier U 16h20 C3-12 A multi-protein bicarbonate dehydration complex essential to carboxysome function in Cyanobacteria George S Espie, U Toronto

Concurrent session 4 – Séance parallèle 4 (pavillon MacDonald hall) Chair – Responsable : Joan Krochko, Plant Biotechnology Institute NSERC-CRSNG

Plant development – Développement des plantes 15h20 C4-13 Arabidopsis ribosomal proteins RPL23αA and -B are

disparately required for normal plant development Rory Degenhardt, U Saskatchewan

15h40 C4-14 Shoot regeneration in Arabidopsis Steven Chatfield, U Guelph 16h C4-15 Time-lapse imaging of Arabidopsis leaf development shows dynamic patterns of procambium formation Megan Sawchuk, U Alberta 16h20 C4-16 The auxin response factor Monopteros regulates leaf formation

through multiple pathways Jim Mattsson, Simon Fraser U

16h40 Poster Session and mixer – Séance d’affiches et cocktail (chapelle Tabaret chapel)

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Monday, June 16 – Lundi 16 juin

8h Registration – Inscription (pavillon Marion hall)

10h Coffee break Pause café (foyer CAREG-CRAGE & Marion lobby)

12h Lunch – Déjeuner (cafétéria UCU cafeteria) Judges’ meeting for student awards – Rencontre des juges pour l’octroi des prix (CRAGE 107 CAREG)

Plenary Session 3 – Séance plénière 3 (pavillon Marion hall) Chair – Responsable : Tim Xing, Carleton U

Plant development – Développement des plantes 8h30 A3-7 Signaling from stem cell to stomata

Fred Sack, U British Columbia

9h10 A3-8 Vascular pattern formation in the Arabidopsis leaf Enrico Scarpella, U Alberta 9h35 A3-9 Role of the Blade-On-Petiole genes

in control of Arabidobsis leaf, flower and inflorescence architecture Shelley Hepworth, Carleton U

Plenary Session 4 – Séance plénière 4 (pavillon Marion hall) Chair – Responsable : Leo Savitch, AAFC-AAC

Cellular communication – Communication cellulaire 10h30 A4-10 Role of 14-3-3 proteins in plant signal transduction

Steve Huber, USDA-ARS & U Illinois 11h A4-11 Small RNA’s and epigenetic regulation in abiotic stress resistance Jian-Kang Zhu, U Calfifornia Riverside 11h30 A4-12 Cellular redox status, plant growth, and defense responses Christine Foyer, U Newcastle upon Tyne

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14h50 Coffee break – Pause café (foyer MacDonald & Marion lobby)

Concurrent session 5 – Séance parallèle 5 (pavillon Marion hall) Chair – Responsable : Sheila Macfie, U Western Ontario

Trace elements and phytoremediation – Microéléments et phytoremédiation 13h30 C5-17 NSERC update – Mise à jour du CRSNG Mario Lamarca, NSERC-CRSNG 13h50 C5-18 Characterization of a mutant strain of Chlamydomonas reinhardtii deficient in the molybdenum cofactor Daniel Fingrut, U Western Ontario 14h10 C5-19 Localization of aluminum in Eriophorum vaginatum leaves Courtney Begy, Nipissing U 14h30 C5-20 Dynamics of mycorrhizal symbiosis & heavy metal phytoremediation: From meta-analytical modeling to in vitro analysis Patrick Audet, U Ottawa

Concurrent session 6 – Séance parallèle 6 (pavillon MacDonald hall) Chair – Responsable : Frédérique Guinel, Wilfred Laurier U

Teaching and education – Enseignement et éducation 13h30 C6-21 IT as the missing lab partner in undergraduate biology Jon Houseman, U Ottawa 13h50 C6-22 Using case studies to promote learning, collaborations, and critical thinking in large classes Colin Montpetit, U Ottawa

Employment and training – Emploi et formation 14h10 C6-23 Keystones for a successful scientific career in Ag-Biotechnology industry Jiangxin Wan, Performance Plants Inc 14h30 C6-24 Protecting Canada’s biodiversity Careers in risk assessment at the Canadian Food Inspection Agency Phil MacDonald, CFIP-ACIA

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Concurrent session 7 – Séance parallèle 7 (pavillon Marion hall) Chair – Responsable : Jas Singh, AAFC-AAC

Abiotic Stress – Stress abiotique 15h20 C7-25 Development of drought tolerant plants through molecular tailoring

of ABA sensing Yafan Huang, Performance Plants Inc 15h40 C7-26 The purple acid phosphatase AtPAP26 is required for efficient acclimation of Arabidopsis thaliana to nutritional phosphate starvation Brenden A Hurley, Queen’s U 16h C7-27 Expression of wheat Vernalization 2 (TaVRN2) delays flowering and enhances freezing tolerance in Arabidopsis Amadou O Diallo, UQAM 16h20 C7-28 Somatic and transgenerational response to stress in Arabidopsis and tobacco Alicja Ziemienowicz, U Lethbridge

Concurrent session 8 – Séance parallèle 8 (pavillon MacDonald hall) Chair – Responsable : Mark Bernards, U Western Ontario

Secondary metabolism and biotechnological applications Métabolism secondaire et applications biotechnologiques 15h20 C8-29 Structure-activity relationship of a wheat flavone o-methyltransferase Francesca Kanapathy, Concordia U 15h40 C8-30 Towards an understanding of the non-darkening trait in cranberry bean (Phaseolus

vulgaris) seed coats K Peter Pauls, U Guelph 16h C8-31 Genomic analysis of 4CL-like acyl-CoA synthetase genes reveals a novel pathway required for pollen wall formation Carl J Douglas, U British Columbia 16h20 C8-32 Metabolism of the folate precursor p-aminobenzoate in plants: Glucose ester formation and vacuolar storage Gale G Bozzo, U Guelph

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16h40 Annual business meeting – Rencontre annuelle de la société (pavillon Marion hall) 17h30 Student oral presentation awards judges’ meeting (CRAGE 107 CAREG) Réunion des juges pour les meilleures présentations orales des étudiant/e/s 18h Banquet: Awards and Gold Medal address (‘The Roof Top Terrace’, NAC, 53 Elgin St) Banquet: Remise des prix et Mot du médaillé d’Or (‘La Terrasse’, CNA, 53, rue Elgin) 18h00 Reception – Réception 18h30 Dinner – Dîner

Gold Medal Address – Mot du Médaillé d’Or Host – Hôte : Peter Pauls, CSPP President – Président SCVP

Tony Glass, University of British Columbia Pissing about with positrons… and plasmids… and phertilizers

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Tuesday, June 17 – Mardi 17 juin

8h Registration – Inscription (pavillon Marion hall)

10h Coffee break – Pause café (foyer CRAGE-CAREG & Marion lobby)

Plenary Session 5 – Séance plénière 5 (pavillon Marion hall) Chair – Responsable : Doug Johnson, U Ottawa

Communication with micro-organisms – Communication avec des micro-organismes 8h30 A5-13 Defensin-like anti-microbial proteins functioning in microbial

interactions with Medicago and Arabidopsis Kathryn VandenBosch, U Minnesota

9h A5-14 Plant genes involved in Agrobacterium-mediated transformation Stanton Gelvin, Purdue U 9h30 A5-15 Arbuscular mycorrhizal fungi boast a surprising number of genetic identities Mohamed Hijri, U Montréal & IRBV

Plenary Session 6 – Séance plénière 6 (pavillon Marion hall) Chair – Responsable : Susan Aitken, Carleton U

Plants in new environments – Plantes dans des nouveaux environnements 10h30 A6-16 Challenges in NASA low-pressure crop production systems:

Separating the effects of hypobaria and hypoxia on lettuce Fred Davies, Texas A&M U

11h A6-17 Plant-soil interactions that affect metal uptake and translocation Sheila Macfie, U Western Ontario

Closing Ceremony – Cérémonie de clôture (pavillon Marion hall)

CSPP 50th Anniversary lecture – Conférence du 50e anniversaire de la SCPV 11h30 World food crisis: Agricultural development and the role of science David Bergvinson, Global Development, Bill & Melinda Gates Foundation 12h Farewell address – Mot de salutation Peter Pauls, CSPP President – Président SCPV

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12h10 Lunch – Déjeuner (cafétéria UCU cafeteria) Meeting of the In-coming Executive – Réunion du comité exécutif intrant (CRAGE 107 CAREG) 13h30-15h Scientific tours - Visites scientifique

Eastern Cereal and Oilseed Research Centre and the Central Experimental Farm, Argiculture and AgriFood Canada

13h15 Bus pick-up (Jean-Jacques Lussier St. next to Lamoureux hall) This event will include: 1. Tour of the research facilities and Central Experimental Farm

2. Round table discussions with Research scientists on the following topics

◊ Abiotic plant stress tolerance ◊ Biotic plant stress tolerance

◊ Plant Transformation technology ◊ Biotechnological applications

◊ Bioinformatics ◊ Genomics and Proteomics Research

3. Collaborative research with AAFC – open discussion 4. Refreshments

Centre de recherche de l’est sur les céréales et oléagineuses de la Ferme expérimentale centrale, Agriculture et Agro-alimentaire Canada

13h15 Embarquement (rue Jean-Jaques Lussier jouxtant le pavillon Lamoureux)

Cette visite comprendra :

1. La visite des emplacements et de la Ferme Expérimentale Centrale 2. Une discussion ‘table ronde’ avec les chercheur/e/s hôtes sur les thèmes suivants

◊ la tolérance des végétaux aux stress abiotiques

◊ la tolérance des végétaux aux stress biotiques

◊ les technologies de biotransformation des végétaux

◊ les applications biotechnologiques

◊ la bioinformatique

◊ les domaines de recherche du génome et du protéome

3. Recherche collaborative avec l’AAC – discussion libre 4. Rafraîchissements

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Teaching and Technology Tour

In 2004 the Department of Biology moved to new state-of-the-art teaching facilities; 10 new labs with the capacity for 392 students during each lab session. Two students work at a station equipped with a new compound microscope and a dissection scope. What is unique is both microscopes are equipped with digital cameras connected to a computer at the workstation - a combination of wet lab bench and computing workstation. Join University of Ottawa Biology professor and 3M National Teaching Fellow Dr. Jon Houseman for a tour of the facilities. Dr. Houseman is a pioneer in establishing multimedia teaching at the University of Ottawa. He was one of the earliest users of the digital teaching technologies that professors at the University of Ottawa now use daily in the instruction of students. During the tour you will see how instructional technology has fostered increased student engagement in the labs and have the opportunity to try out the equipment yourself.

There is no charge for this tour. To participate and receive more information, please sign up at the Registration Desk.

Visite ‘Enseignement et Technologie’

En 2004, le Département de biologie déménageait dans ses nouveaux locaux dotés d’installations des plus avancées, incluant dix nouveaux laboratoires avec la capacité d’enseigner à 392 étudiant/e/s durant chaque session de laboratoire. Deux étudiant/e/s travaillent ensemble à une station équipée d’un microscope optique et à dissection. Ce qui est unique ici est que ces deux microscopes sont aussi équipés de caméras numériques connectées à un ordinateur à chaque station – une combinaison parfaite pour des travaux de type expérimental et de synthèse. Joignez-vous au Professeur Jon Houseman de l’Université d’Ottawa et Boursier national de l’enseignement 3M pour une visite de ces installations. Professeur Houseman est un pionnier dans l’élaboration de l’enseignement multimedia à l’Université d’Ottawa. Il est parmi les tous premiers a avoir développé et utilisé les technologies numériques pour l’enseignement des étudiant/e/s, celles que les professeurs de l’Université d’Ottawa utilisent maintenant quotidiennement. Pendant cette visite, voyez comment ces technologies stimulent les étudiant/e/s dans leur apprentissage en laboratoire et ayez vous-même l’occasion de les tester.

Il n’y a aucuns frais pour cette visite. Pour participer et recevoir de plus amples informations, veuillez vous y inscrire au bureau des inscriptions.

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Abstracts – Résumés

Gold Medal Address Mot du médaillé d’Or

Pissing about with positrons… and plasmids… and phertilizers Anthony DM Glass University of British Columbia aglass@interchange.ubc.ca Before the advent of plant molecular biology two powerful techniques dominated ion transport studies, namely, influx kinetics (mainly concentration dependence) and electrophysiology. At UBC I was fortunate to have a laboratory located only kilometres (minutes) from a large cyclotron enabling me to receive regular shipments of the short-lived 13N tracer (half-life 10 min) for twenty years. This tracer has allowed my coworkers and I to kinetically characterize three nitrate transporters and two ammonium transporters in roots of a number plant species. Using electrophysiological methods we established that all three nitrate transporters were active and proton-mediated, while only the low concentration ammonium system was active. With the advent of molecular biology we have cloned high-affinity nitrate transporters from Arabidopsis and barley. In collaboration with Scottish scientists we have extended our studies to investigate both nitrate and nitrite uptake by the fungus Aspergillus nidulans, recently providing the first definitive evidence for post-translational regulation of the high-affinity nitrate transporter. Combining molecular and biochemical methods we have investigated the regulation of both high-affinity nitrate and ammonium transporters. My interests in the more practical aspects of ion transport have led me to ongoing studies of fertilizer utilization in the greenhouse industry and in the field.

Plenary Session 1: Bioenergy and biofuels

Séance plénière 1 : Bioénergie et biocarburants

A1-1 The “genealogy” of the science of plant physiology in Canada Connie Nozzollilo University of Ottawa Two men are prominent in the development of the study of plant physiology in Canada. One is Professor G. H. Duff at the University of Toronto, the other is Professor G. W. Scarth at McGill University. Although neither man lived long enough to be founding members of the CSPP-SCPV, they were strongly in favour of its formation and many of their students are founding members. The talk will provide a

brief insight into the influence of these two men and their students on the CSPP-SCPV as we know it today. A1-2 Sustainable bioeconomy systems: A critical role for the plant sciences David B Layzell, PhD, FRSC, Executive Director Institute for Sustainable Energy, Environment & Economy, University of Calgary, Calgary, AB, Canada, T2N 1N4 dlayzell@ucalgary.ca In a world where global temperatures and energy prices are rising rapidly, concerns about climate change and energy security have focused attention on optimizing the role that agriculture and forestry can play in providing renewable energy and environmental values, in addition to food, feed and fibre. In this talk, I will explore the challenges and opportunities associated with such a “Sustainable Bioeconomy”, especially within a Canadian context. The talk will begin with an overview of the energy and climate change drivers that are moving industry and governments towards bioeconomy solutions, before exploring some ideas about what a transformative bioeconomy might look like in the future. I will end the talk by identifying some of the ways in which Plant Science research could contribute sustainable solutions to these major challenges that society faces in the 21st century. A1-3 Lignin modification for improvement of dedicated bioenergy crops Richard A Dixon, F Chen, L Jackson, J Nakashima, G Shadle, and R Zhou Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA radixon@noble.org Economic and environmental factors favor the adoption of lignocellulosic bioenery crops for ethanol production. However, lignocellulosic biomass is recalcitrant to saccharification, and this is, at least in part, due to the presence of the phenylpropanoid-derived cell wall polymer lignin. Alfalfa is the major forage legume in the United States, and is also attracting interest as a bioenergy crop. The biochemistry and molecular biology of the monolignol pathway in alfalfa will be reviewed. Analysis of alfalfa plants in which lignin content and composition had been modified through independently down-regulating each of six enzymes in the lignin pathway revealed that reduction in lignin content, but not altered lignin composition, increased sugar release from dried biomass by both acid pre-treatment (hot sulfuric acid) and digestion by a cellulase mixture. In both cases, the extent of sugar release was inversely proportional to lignin content. Acid pre-treatment could effectively be omitted in the processing of biomass with the lowest lignin levels. The gains in fermentable sugar production will be

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discussed in relation to other phenotypic consequences of lignin modification. We are utilizing forward genetic screens in the model legume Medicago truncatula for the discovery of novel genes impacting lignification and cell wall deconstruction. We will also outline new projects targeting cell wall recalcitrance in switchgrass as a part of the DOE-funded Bioenergy Sciences Center.

Plenary Session 2: Plant natural health products

Séance plénière 2 : Produits naturels des plantes

A2-4 Plant natural products and society: The science challenges from bioenergy (lignin and related compounds) to medicinals Norman G Lewis Institute of Biological Chemistry, Washington State University, Pullman, USA, 99164-6340 lewisn@wsu.edu The world is once again confronted with the necessity and urgency to provide renewable, sustainable, and stable sources of bioenergy/biofuels, intermediate chemicals, and specialty chemical products from renewable plant resources. Unlike the previous energy crisis of the 1970s, there is the very real challenge facing humanity that the remaining petroleum feedstocks will begin to dwindle in the next two to three decades. During this time frame, the available non-renewable petroleum resources are anticipated to be unable to keep up with demand. One possible partial solution to address this projected shortfall is to identify sources of these chemicals that can be obtained from plants in a sustainable manner. There is much interest in overcoming the recalcitrance of lignocellulosics and thus facilitating the conversion of lignocellulosics to afford ethanol, although to date this has not been demonstrated to be economically feasible with currently available technologies. Nevertheless, the US Congress has essentially mandated that technologies be developed to produce 60 billion gallons of ethanol by 2030. This, in turn, is considered to require approximately 1.3 billion tons of lignified (woody) biomass annually for this purpose.In this presentation, the biotechnological lignin-reductions effectuated thus far are described which, in general, have resulted in compromised vascular apparatus effects and perhaps higher susceptibilities to pathogen attacks. Such plant lines are probably unsuitable for large scale cultivation. Accordingly, new and novel approaches are being both conceptualized and developed if the lignin challenge is to be overcome for purposes of generating biofuels/bioproducts and bioenergy from lignocellulosics. This presentation thus addresses some new areas of exploration involving redirection of carbon flux away from the formation of lignin to that of high-value, liquid, plant derived aromatics which can be used for bioenergy/biofuels and other specialty purposes. Discussed herein is the progress made as regards the pertinent enzymes, genes, and specific biochemical precursors involved that have been isolated and which lend themselves to exploitation through bioengineering. These advances are also placed in context with related work leading to (phenolic) plant medicinals, many of which

share the same biochemical pathway steps. Potentially, success in this endeavor could lead to development of a multibillion dollar per year industry within the United States alone. A2-5 Opening ‘Pandora’s Box’: Genes and alkaloids galore – Now what? Peter Facchini Department of Biological Sciences, University of Calgary, Calgary, AB, Canada, T2N 1N4 pfacchin@ucalgary.ca Benzylisoquinoline alkaloids (BIA) are a group of ~2,500 bioactive metabolites found mainly in the Papaveraceae, Ranunculaceae, Berberidaceae and Menispermaceae. Prominent compounds include the narcotic analgesic morphine, the cough suppressant codeine, the muscle relaxant papaverine, and the antimicrobial agents sanguinarine and berberine. More than 20 cDNAs encoding BIA biosynthetic enzymes have been isolated and the pace of gene discovery is increasing with the application of new technologies. We are using comparative genomics to uncover the immense biochemical diversity of BIA biosynthetic enzymes. Expressed sequence tag (EST) databases for a variety of cell cultures representing BIA-producing plant species from four different plant families have provided a wealth of enzymes with novel catalytic functions and substrate specificities. Several functional genomics platforms, including RNAi, viral-induced gene silencing (VIGS) and TILLING, are being developed and show promise for the characterization of new genes. However, the status of plants that produce BIAs as non-model systems currently limits the efficacy of these methods, and results in much reliance on the labour-intensive process of empirically testing the enzymatic function of recombinant proteins in vitro. To improve our ability to predict the substrates for uncharacterized enzymes potentially involved in BIA metabolism, we have also applied advanced metabolic profiling of the alkaloids in each system using Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Metabolomics is also an effective way to test the in vivo relevance of the substrate range of recombinant enzymes assayed in vitro. The isolation and characterization of several new N-methyltransferases involved in BIA metabolism in three different plants will be used to demonstrate the potential of integrating metabolomics, transcriptomics, and functional biochemical genomics. We are also pursuing the development of a biochemical visualization platform to integrate large datasets and improve the efficiency of gene discovery. In addition to the potential applications of an expanded enzymatic toolbox, these approaches are providing new insights into the evolution of plant natural product pathways.

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A2-6 Integrative therapeutic trait selection for bioproduct crop plant improvement Shannon Cowan University of British Columbia Shannon.cowan@ubc.ca Cultivation of plants with therapeutic properties for bioproduct development has many potential benefits: conservation, wider growth range, economic incentive, and crop improvement through selection, breeding and biotechnology. Concurrently, metabolic profiling and development from plant to product has surged, with increasingly refined results in the marketplace. Nonetheless, natural health bioproducts remain plagued by poor identity, quality, and efficacy issues: one of the major contributors being where source plant quality has lagged on the industrial scale. Crop improvement seeks to address these challenges through inclusion of therapeutic traits with breeding for agronomic traits. Trait selection is complicated by unknown therapeutic mode of action, multiple or synergistic therapeutic phytochemicals, genotype by environment interactions, species-specific phytochemical accumulation, and more. We applied an integrative model to study therapeutic trait variability in Echinacea angustifolia (Asteraceae) and Echinacea hybrids at different sites in British Columbia through metabolic profiling, bioassay-guided trait and genotype selection and measures of environmental effects on therapeutic bioaccumulation. Echinacea is cultivated worldwide for the bioproduct/health product industry and has demonstrated evidence of significant and varied biological and clinical activities. The novel benefits (and costs) of this model and a synopsis of selected results will be discussed.

Plenary Session 3: Plant development Séance plénière 3 :

Développement des plantes A3-7 Signaling from stem cells to stomata Fred Sack Botany, Univ. British Columbia, 6270 University Blvd., Vancouver, BC, Canada, V6T 1Z4 fsack@interchange.ubc.ca Stomata are cellular valves essential for shoot gas exchange, plant productivity, and carbon and water cycles in the biosphere. In Arabidopsis, stomata are produced in a dispersed stem cell compartment that also produces much of the shoot epidermis. The stomatal pathway is an accessible system for analyzing core developmental processes including position-dependent patterning via intercellular signaling, and the regulation of the balance between proliferation and cell specification. This talk presents an integrated analysis of key events, genes, and pathways in Arabidopsis stomatal development.

A3-8 Vascular pattern formation in the Arabidopsis leaf MG Sawchuk1, TJ Donner1, P Head1, D Marcos2, J Friml3, T Berleth2, and Enrico Scarpella1 1Dept of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada; 2Dept of Cell and Systems Biology, University of Toronto, Toronto, ON, Canda, M5S 3B2; 3Dept of Plant Systems Biology, VIB/Ghent University, B-9052 Ghent, Belgium enrico.scarpella@ualberta.ca For centuries, the formation of vein patterns in the leaf has intrigued biologists, mathematicians and philosophers. In leaf development, files of vein-forming procambial cells emerge from seemingly homogeneous subepidermal tissue through the selection of anatomically inconspicuous preprocambial cells. Although the molecular details underlying the orderly differentiation of veins in the leaf remain elusive, gradually restricted transport paths of the plant hormone auxin have long been implicated in defining sites of vein formation. Several recent advances now appear to converge on a more precise definition of the role of auxin flow at different stages of vascular development. The picture that emerges is that of vein formation as a self-organizing, reiterative, auxin transport-dependent process. A3-9 Role of the BLADE-ON-PETIOLE genes in control of Arabidopsis inflorescence architecture and floral-meristem identity M Xu and Shelley Hepworth 1125 Colonel By Drive, Ottawa, ON, Canada, K1S 5B6 shelley_hepworth@connect.carleton.ca During the transition to reproductive development the shoot apical meristem switches from making vegetative shoots to making flowers. LEAFY (LFY) and APETALA1 (AP1) are key regulators of this transition and their expression in lateral organ primordia on the flanks of the inflorescence apical meristem confers floral fate. Here, we examine the role of two NPR1-like growth regulators, BLADE-ON-PETIOLE (BOP) 1 and 2, in control of inflorescence architecture and the floral transition. BOP1/2 are expressed in initiating lateral organ primordia at all stages of development and have been shown previously to control the architecture of leaves, flowers, and fruits. Our data indicate that BOP1/2 function together with LFY and AP1 to promote floral fate and to control the architecture of the floral shoot. Double mutants bop1 bop2 show only subtle defects in floral architecture but in combination with lfy or ap1 generate synergistic defects in floral organ phyllotaxy, internode elongation, bract formation, and pattern of meristematic activity. Mutations in bop1 bop2 also enhance floral-organ identity defects associated with weak alleles of lfy and ap1 and enhance floral bract formation in LATE-MERISTEM IDENTITY1, a downstream target of LFY. Molecular analysis shows that BOP1/2 function redundantly with LFY and AP1 in down-regulation of the inflorescence identity gene AGAMOUS-LIKE24, an important first step in the conversion of shoots to flowers during the transition to reproductive development.

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Plenary Session 4: Cellular communication

Séance plénière 4 : Communication cellulaire

A4-10 Proteins and plant signal transduction 1Man-Ho Oh, 2X Wang, 2SD Clouse, and 1Steven C Huber 1US. Dept. of Agriculture, Agricultural Research Service, and Dept. of Plant Biology, University of Illinois, Urbana, IL 61801, USA; 2Dept. of Horticultural Sciences, NC State University, Raleigh, NC 27695, USA schuber1@uiuc.edu The ‘14-3-3 proteins’ are highly conserved phosphoserine/phosphothreonine-binding proteins that can potentially interact with a wide variety of soluble or membrane-bound ‘client’ proteins. One major focus of our work is to identify specific client proteins in vivo. We are taking a broad discovery approach and are also specifically exploring the role of 14-3-3 proteins in brassinosteroid (BR) signaling. The BRs are growth-promoting hormones that also enhance stress tolerance, and pharmacological and genetic evidence suggests that 14-3-3 proteins are essential, positive regulators of BR signaling. It is well known that at least two leucine-rich repeat receptor-like kinases are involved in BR perception and signal transduction: the receptor kinase BRASSINOSTEROID INSENSITIVE 1 (BRI1) and its co-receptor, BRI1-Associated receptor Kinase 1 (BAK1). 14-3-3 proteins co-immunoprecipitate with BRI1-Flag in a BR-stimulated manner in vivo suggesting that their role in BR signaling may involve interaction with the receptor kinases themselves. Indeed, the soluble cytoplasmic domains of BRI1 and BAK1 expressed as recombinant proteins can directly bind 14-3-3 proteins in vitro establishing BRI1 and BAK1 as 14-3-3 binding proteins. The in vitro binding of recombinant 14-3-3 ω to the recombinant cytoplasmic domain of BRI1 and BAK1 is dependent on autophosphorylation of the receptor kinase and is strongly stimulated by Mg2+. Interestingly, the binding of 14-3-3ω to BRI1 and BAK1 in vitro is specifically regulated by tyrosine autophosphorylation of the receptor kinases. While BRI1 and BAK1 are classified as serine/threonine protein kinases, we now demonstrate that both kinases can also autophosphorylate on tyrosine residues and thus are dual specificity kinases. Specific sites of tyrosine autophosphorylation on BRI1 have been identified and we are currently trying to determine which of these sites controls 14-3-3 binding, and whether phosphotyrosine is directly involved in 14-3-3 binding or whether the effect is indirect. Identification of BRI1 and BAK1 as dual specificity kinases raises the potential that tyrosine signaling may be important with plant receptor kinases as it is with animal receptor kinases. Indeed, a distinct phenotype is associated with expression of a site-directed mutant of BRI1 lacking a major site of tyrosine autophosphorylation. Furthermore, the potential for tyrosine phosphorylation to be involved in 14-3-3 binding adds a new dimension to the functionality of these signaling proteins. In the future, it may be possible to manipulate the binding of 14-3-3 to the BR receptor in such a way that crop growth and stress tolerance are increased.

A4-11 Small RNAs and epigenetic regulation in abiotic stress resistance Jian-Kang Zhu Dept of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA The research in my lab is focused on the molecular mechanisms of salt, drought and cold stress signaling and resistance. Recently, we began to study the roles of microRNAs and small interfering RNAs in abiotic stress response pathways, the mechanisms of active DNA demethylation and small RNA-directed DNA methylation, and the contribution of these epigenetic mechanisms to stress resistance. Recent results concerning abiotic stress-regulation of small RNAs and DNA methylation in Arabidopsis will be presented. A4-12 Cellular redox status and plant growth and defence responses Christine H Foyer School of Agriculture, Food and Rural Development, Agriculture Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK christine.foyer@ncl.ac.uk It has long been recognised that reactive oxygen species (ROS) and antioxidants are important in plant responses to biotic and abiotic defence stresses. In particular, the oxidative burst leading to ROS accumulation is viewed as an important feature of the repertoire of plant defence responses that occur upon pathogen attack. Current concepts of plant defence signalling cascades implicate light and ROS in plant innate immune responses, programmed cell death and the induction of systemic acquired resistance (SAR). The abundance of the low molecular antioxidants, ascorbate and glutathione, is also important in determining the threshold for the orchestration of innate immune resistance. Moreover, cytosolic glutathione appears to be involved in the signal transduction cascade leading to SAR responses such as the expression of pathogenesis resistance proteins. To analyze the impact of ROS and antioxidant metabolism on cell death and SAR response signalling, we have used phenotypic, metabolic and transcriptomic analysis of tobacco and Arabidopsis mutants. Aspects of these studies and key conclusions will be described. In particular, it will be shown that (1) the harpin-induced cell death response in tobacco leaves occurs in darkness and is accelerated in the absence of oxygen (2) that ascorbate signalling pathways lead to enhanced defences against biotrophic pathogens and altered hormone signalling with transcriptome changes that closely resemble those observed in the Arabidopsis abscisic acid signalling mutant, abi-4.

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Plenary Session 5: Communication with micro-organisms

Séance plénière 5 : Communication avec des

micro-organismes A5-13 Defensin-like anti-microbial proteins functioning in microbial interactions with Medicago and Arabidopsis KA VandenBosch1, S Nallu1, M Tesfaye1, L Wang1, CJ Botanga1, SK Gomez2, M Harrison2, J Glazebrook1, F Katagiri1, MA Graham3, and KAT Silverstein1 1 Dept of Plant Biology, University of Minnesota, St. Paul, MN; 2Boyce Thompson Institute for Plant Research, Ithaca, NY; 3 USDA-ARS, Iowa State University, Ames, IA vande102@umn.edu Plants use many strategies against pathogens, including activation of defensin genes, which produce antimicrobial proteins containing a signal peptide and a small mature protein with a characteristic cysteine-stabilized alpha/beta motif. We have shown that genes encoding defensin-like proteins (DEFLs) have been grossly under-predicted in plants. Typically, DEFLs number in the hundreds per genome, but information on expression and function of most DEFLs is lacking. We developed a custom Affymetrix chip to evaluate DEFL expression in Arabidopsis thaliana and Medicago truncatula across diverse developmental stages and in interactions with microbes. In both species, a few DEFLs are constitutively expressed in vegetative tissues or are induced by pathogens in roots or leaves. In Arabidopsis, the largest number of DEFLs is expressed in reproductive tissues. In Medicago, most are induced during nodulation, while a few are specifically induced in mycorrhizal roots. Using rhizobium mutants as inocula, we have found that Nod factor is not sufficient and nitrogen fixation is not required for induction of DEFLs. Nodule DEFLs show several patterns of induction in Medicago, but appear to be absent from determinate nodule-forming legumes such as soybean. Novel motifs common to nodule DEFL promoters are predicted to be cis elements that direct organ-specific expression in Medicago. Microarray results will be integrated with other available expression data. The genomic context of DEFL genes will also be considered, as will potential DEFL functions. A5-14 Plant genes Involved in Agrobacterium-mediated transformation Stanton B Gelvin Dept of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA gelvin@bilbo.bio.purdue.edu Agrobacterium-mediated plant transformation is a complex process involving the interaction of components transferred from the bacterium with plant-encoded proteins. During the past decade, we have used several approaches to identify and characterize plant genes important for transformation. These approaches include forward and reverse genetic analyses of Arabidopsis

mutants to identify mutants that are resistant or hyper-susceptible to Agrobacterium transformation (rat or hat mutants), yeast and plant protein-protein interaction assays to identify plant proteins that interact with transferred Agrobacterium effector proteins, and microarray/bioinformatics approaches to identify plant genes that are rapidly induced or repressed when Agrobacterium infects plants. We have identified >125 rat or hat mutants. Characterization of these mutants indicates that they are affected at various transformation stages. We have over-expressed several of these rat/hat genes in transgenic Arabidopsis, Brassica napus, or maize. Over-expression of some of these genes increases transformation by affecting various transformation steps, including Agrobacterium attachment to plant cells, alterations in cellular metabolites, and transgene expression. Of particular interest are genes encoding core histone proteins. Over-expression of many of these genes substantially increases transformation by increasing expression of incoming (but not previously integrated) transgenes. Enhanced transgene expression results from increased stabilization of transgene DNA sequences in the plant cell cytoplasm. This transgene stabilization also occurs during direct DNA introduction into plant cells. In addition, we have identified a myb-like transcription factor that appears to be a negative global regulator of Agrobacterium-mediated transformation. Manipulation of this gene may also result in enhanced transformation of previously recalcitrant plants. A5-15 Arbuscular mycorrhizal fungi boast a surprising number of genetic identities E Zimmerman, E Boon, J Marleau and Mohamed Hijri Université de Montréal, IRBV, 4101 rue Sherbrooke est, Montréal, QC, Canada, H1X 2B2 Mohamed.Hijri@umontreal.ca "One organism, one genome" sounds like a reasonable rule of thumb, yet may not apply to arbuscular mycorrhizal fungi (AMF). These fungi are symbiotic with the roots of more than 80% of plants, where they improve plant nutrient (especially phosphate) uptake. In turn, the plant provides both carbohydrates and lipids to the fungus. AMF have existed essentially unchanged morphologically for at least 460 million years, despite lacking sexual reproduction. We have recently shown that these fungi have evolved to contain multiple genomes, and that these different genomes are transferred to subsequent generations [1]. Biologically, AMF are unusual in a number of ways. They reproduce exclusively via multinucleate spores which can contain hundreds to thousands of nuclei. A further difficulty in their study relates to the fact that the AMF are obligate biotrophs and consequently must be maintained on living plants. Moreover, the genetics of the AMF are still a mystery. The relationship amongst genetics, genomics, physiology and morphology in these fungi is a fascinating enigma and an area of active research. The principal problem is that the conventional tools used to study monogenomic organisms such as humans, mice, flies or yeast are inadequate for use with a heterokaryotic organism, so new conceptual and genetic tools must be developed to understand the Glomeromycota. In this context, our objectives are first, to understand how AMF spores are formed and how their genes are transferred. AMF produce spores with up to 2,000 nuclei by simple

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structural differentiation of hyphal tips, but the number of original nuclei from which the spore formed is not definitively known. Ideally, the establishment of a robust transformation system would be a prerequisite for studies of the functional genomics and reproductive mode of AMF. However, there are as yet no efficient methods to transform the AMF. We have therefore chosen live cellular imaging as an alternative to study the AMF life cycle and how they accomplish genetic exchanges in the absence of sexual reproduction. Second, we wish to quantify the amount of genetic variation due to segregation and drift using markers corresponding to different alleles of the two-copy gene PLS (POL1-like sequence), found in the AMF species Glomus etunicatum. A Monte Carlo simulation will be carried out which will map the number of distinct gene variants as a function of the total number of sequences sampled. This curve will predict the maximum number of distinct variants expected to exist, giving a preliminary estimate of the diversity of genotypes present in a single AMF species. Third, we will check whether the genetic variation observed within genomes of single AMF isolates, which comprises both protein-coding genes and ribosomal RNA genes, is expressed or not in AMF transcriptome. The output of this research will improve our understanding of AMF, and of the processes that govern this major eukaryotic symbiosis, in hopes of reducing fertilizer use and its negative impact on the Earth’s chemical equilibrium. The output of this research will improve our understanding of AMF, and of the processes that govern this major eukaryotic symbiosis, in hopes of reducing fertilizer use and its negative impact on the Earth’s chemical equilibrium.

Plenary Session 6:

Plants in new environments Séance plénière 6 :

Plantes dans de nouveaux environnements

A6-16 Hypobaria, hypoxia and ethylene influence growth and gas exchange of lettuce ⎯ Challenges in NASA production systems Fred T Daviesa, C Hea, and R E Laceyb aDept of Horticultural Sciences and interdisciplinary program of Molecular and Environmental Plant Sciences (MEPS), Texas A&M University, College Station, Texas 77843-2133 USA; bDept of Biological & Agricultural Engineering and MEPS, Texas A&M University, College Station, Texas 77843-2117 USA f-davies@tama.edu There are engineering advantages in growing plants at hypobaric (reduced atmospheric pressure) conditions in biomass production for extraterrestrial base or spaceflight environments. Elevated levels of ethylene occur in enclosed crop production systems and in spaceflight environments leading to adverse plant growth and sterility. The Low Pressure Plant Growth system (LPPG) was designed to grow plants under ambient or hypobaric conditions. Objectives of this research were to characterize the influence of hypobaria on growth, gas exchange and ethylene evolution of lettuce (Lactuca sativa L. cv.

Buttercrunch). Lettuce plants were grown under variable total gas pressures [25 and 101 kPa (ambient)] at 6, 12 or 21 (normal air) kPa pO2. While plant growth was comparable between ambient and low pressure lettuce during the 10-day study, growth was lower at 6 kPa pO2 than 12 or 21 kPa pO2. There was comparable CO2 assimilation (net photosynthesis) and lower dark respiration rate in low (25/12 kPa pO2) than ambient (101/21 kPa pO2) pressure plants. The ratio of CO2 assimilation/dark respiration was higher at low than ambient total pressure, particularly at 6 kPa pO2 ⎯ indicating a greater efficiency of CO2 assimilation/dark respiration with low pressure plants. Hypobaric plants were more resistant to hypoxic conditions (6 kPa pO2) that reduced gas exchange and plant growth. There were negative linear correlations between increasing ethylene concentrations in the LPPG with net CO2 assimilation, dark-period respiration, total leaf area, and relative growth rate (RGR) in both hypobaric and normal total pressure conditions. A decline in CO2 assimilation and dark-period respiration were observed with both exogenous and endogenous ethylene treatments. A6-17 Plant-soil interactions that affect metal uptake and translocation Sheila M Macfie Dept of Biology, University of Western Ontario, London, ON, Canada, N6A 5B7 smacfie@uwo.ca In theory, phytoremediation is a very promising technology for removal of metal ions from contaminated soil. Fast-growing plants that accumulate metals in easily harvestable organs are obvious targets for use. In reality, the rates at which metals are removed from soil can be very slow, and many plants retain metals in their roots. In addition, incomplete understanding of the complex processes in the soil that control metal bioavailability, as well as of the physiological factors that control metal uptake and translocation, has prevented the phytoremediation industry from reaching its potential. Our approach includes growing a number of plant species in soils that have been collected from contaminated areas. We assessed the contributions of several physico-chemical factors in the soil to metal accumulation in five plant species using Principle Components Analysis (PCA). When considering metal taken up by entire plants (roots and shoots together), PCA revealed that pH, organic matter content, and particle size composition were the best candidates for predicting metal bioavailability and uptake. However, different plant species grown in the same soil had very different patterns of metal accumulation. For example, in radish a very small proportion of the bioavailable metal accumulated within the root while high concentrations were found in the leaves. In contrast, the highest concentrations of metals in carrots were found in the root and very little was translocated to the leaves. To gain a better understanding of these plant-soil-metal interactions, our current work includes investigations of plant-induced changes in the rhizosphere that influence metal uptake.

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Concurrent Session 1: Carbon and nitrogen metabolism

Séance parallèle 1 : Métabolisme du carbone et de l’azote

C1-1 Functional characterization of a sucrose transporter in winter wheat (Triticum aestivum cv. McClintock) Chelsey McDougall, Y Sun, A Brûlé-Babel, and F Razem 222 Agriculture Bldg, 66 Dafoe Rd, Winnipeg, MB, Canada, R3T 2N2 umtarrcj@cc.umanitoba.ca Photosynthate transport from source to sink organs is an essential process in plants and the efficiency of this transport is critical for grain and tuber filling in various crops, including wheat and potato. Sucrose is the most prominent form of photosynthate transported in many species due to its mobility and stability. Active transport of sucrose is achieved by proteins from the proton-coupled sucrose uptake transporter (SUT) family. We have cloned a wheat (Triticum aestivum cv. McClintock) sucrose transporter (TaSUT), which shares high homology with other sucrose transporters from cereals, and characterized its sucrose uptake kinetics. To test if TaSUT is capable of transporting sucrose, TaSUT cDNA was expressed in an invertase-knockout yeast strain previously transformed with a potato sucrose synthase. This strain is capable of utilizing internal sucrose but is unable to internalize sucrose itself. TaSUT-transformed yeast was capable of growing on media with sucrose as the sole carbon source, providing evidence that TaSUT is functional in transporting sucrose. To characterize TaSUT sucrose uptake, we expressed the TaSUT cDNA into a different invertase-knockout yeast strain that is unable to take up sucrose or hydrolyze it internally. Yeast cells expressing the TaSUT cDNA are able to take up sucrose in a pH-dependent manner, with optimal sucrose uptake at pH 4.0. Sucrose uptake was inhibited by electron transport chain inhibiters, which indicates that SUTs operate via a proton-coupled transport mechanism. We further tested the kinetics of TaSUT sucrose uptake and compared it with that of StSUT1 from potato. TaSUT takes up sucrose with a Km value of approximately 17 mM. Comparison with StSUT1, which has a Km value of 1.7 mM, clearly indicates that TaSUT1 is a low affinity sucrose transporter. Additionally, several mono- and polysaccharides are able to compete with sucrose transport to varying extents. Here we present our progress to date on the characterization of this TaSUT sucrose transporter.

C1-2 Daphnetin is a potential modulator of phospho-ribulokinase during cold acclimation of wheat Khalil Kane1, RK Ibrahim2, N P A Huner3, F Yukihara4, and F Sarhan1 1Dép des Sciences biologiques, Université du Québec à Montréal, C.P. 8888 Succ Centre-ville, Montréal, QC, Canada H3C 3P8; 2Plant Biochemistry Laboratory and Centre for Structural–Functional Genomics, Concordia University, 1455, boul de Maisonneuve West, MTL, QC, Canada, H3G 1M8; 3Dept of Plant Sciences, University of Western Ontario, London, ON, Canada, N6A 5B7; 4

University of Hokkaido, Sapporo, Japan kanekha@hotmail.com In a previous study, we identified a novel O-methyltransferase that is regulated by cold and PSII excitation pressure. The enzyme catalyzes the methylation of 7,8-dihydroxycoumarin, daphnetin to its 8-methyl derivative. To determine the biological significance of this reaction, we tested the inhibitory effect of both the daphnetin and methylated derivative. Our results show that daphnetin strongly inhibits both protein kinase A and C whereas the methylated form alleviates this inhibition suggesting that daphnetin methylation, catalyzed by the cold-regulated OMT, could modulate specific kinase activity during cold acclimation. To identify the potential kinase that may interact with daphnetin in wheat extract during cold acclimation, the cold acclimated extract was purified by ammonium sulphate precipitation, DEAE separation and affinity chromatography on a daphnetin derivate (7,8 dihydroxy-4-coumarin acetic acid)-EAH sepharose column. Mass spectrometry analysis indicates that phosphoribulokinase is the daphnetin target in wheat. Phosphoribulokinase catalyzes the generation of ribulose 1,5-bisphosphate from ribulose-5-phosphate (Ru5P) and ATP. This reaction is crucial for CO2 assimilation by the Calvin’s reductive pentose pathway. To test the inhibitory effect of daphnetin on the activity of wheat phosphoribulokinase, the gene was cloned and expressed in E.coli. Both recombinant protein and the native phosphoribulokinase from plants were inhibited by daphnetin in a dose-dependant manner. Northern blot analyses showed that phosphoribulokinase is regulated by light and cold. Work is in progress to determine the regulatory role of wheat and rye phosphoribulokinases during the growth under high CO2 concentrations and different stress conditions.

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C1-3 The effect of nitrogen concentration on compatible solutes during salinity stress in Thellungiella salsuginea Ashley Tattersall, D Guevara, Y Wang, P Summers, and E Weretilnyk McMaster University, Life Science Building, 1280 Main St, Hamilton, ON, Canada, L8S 4K1 tatterad@mcmaster.ca Many salt tolerant plants are able to compartmentalize deleterious ions, such as Na+, in vacuoles to minimize perturbing impacts on cellular processes. This localization requires the accumulation of osmotically active but non-perturbing solutes in the cytosol. The amino acid proline is one organic osmoprotective solute that accumulates in many stressed plants including Thellungiella, the halophytic relative of Arabidopsis. We subjected Thellungiella plants of the Yukon genotype to a step-wise salinization procedure by irrigating plants first with 50 mM NaCl and then increasing their salt exposure every 3d to a final concentration of 500 mM. This treatment led to a salt-responsive accumulation of proline in leaf tissue. However, leaf metabolite profiles of Thellungiella growing on highly saline soils in the Yukon show proline levels consistent with well-watered, non-salinized control plants in growth cabinets. To this apparent contradiction between field and cabinet-grown plants, we grew seedlings on defined tissue culture media in the presence or absence of salt (100 mM NaCl) and under conditions of low (0.1 mM) or high (1 mM) nitrogen (N). Salt exposure had no impact on shoot fresh weights, but plants on low N were significantly smaller than those growing on high N. Leaf metabolites were analyzed by gas chromatography/mass spectrometry and the data was subjected to ANOVA, principle component analysis and hierarchal cluster analysis. We found proline content to be significantly higher in salt-stressed plants grown on 1 mM N compared to salt-stressed plants on 0.1 mM N. On low N media, salt-stressed plants appear to accumulate carbohydrates in place of proline. Our results suggest that available N influences the nature of the organic solutes accumulated by Thellungiella upon salt exposure. This metabolic plasticity may underlie the exceptional capacity for Thellungiella to survive and even thrive in extreme environments. C1-4 Molecular and regulatory properties of a novel monoubiquitinated phosphoenolpyruvate carboxy-lase heterotetramer from germinated castor oil seeds RG Uhrig and William C Plaxton

Dept of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6 plaxton@queensu.ca PEP carboxylase (PEPC) is a tightly regulated cytosolic enzyme situated at the core of plant primary C-metabolism. While its anaplerotic role and phosphorylation in developing seeds have been well documented, its function and properties in germinated seeds are poorly understood. Immediately following castor oil seed (COS) imbibition, endosperm PEPC activity increased in parallel with the accumulation of equivalent amounts of immunoreactive 110- and 107-kDa plant-type PEPC

polypeptides (p110 & p107, respectively). PEPC was purified ~2,000-fold from 300 g of 4-d germinated COS to near homogeneity, yielding >5 mg of a novel 440-kDa Class-1 PEPC heterotetramer composed of a 1:1 ratio of non-phosphorylated p110 and p107 subunits. MALDI-TOF MS revealed that both subunits arise from the same castor PEPC gene (RcPPC3; previously documented to encode the p107 subunit of a phosphorylated 410-kDa Class-1 PEPC homotetramer from developing COS). Interestingly, MALDI-qTOF MS/MS, N-terminal microsequencing by Edman degradation, and anti-ubiquitin-IgG immuno-blotting demonstrated that p110, but not p107, was monoubiquitinated (both subunits share identical N-terminal sequences). Kinetic analyses revealed significant differences in allosteric effector sensitivity of the heterotetrameric vs. homotetrameric Class-1 PEPCs of germinated vs. developing COS. Polyubiquitination is well known for its pivotal role in targeting many proteins for 26S proteosomal degradation. However, non-destructive regulatory and/or protein:protein interaction roles for enzyme monoubiquitination have recently emerged. Our unexpected discovery of PEPC monoubiquitination in germinated COS represents an as yet unrecognized form of post-translational modification for this important CO2 fixing plant enzyme.

Concurrent Session 2: Biotic stress Séance parallèle 2 : Stress biotique

C2-5 Inducible expression of antimicrobial peptides as an approach to enhance plant resistance to a variety of phytopathogens Dmytro P Yevtushenko and S Misra Centre for Forest Biology, Dept of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada, V8W 3P6 dmytro@uvic.ca The rapid accumulation of defensive transgene products in plants only upon pathogen invasion has distinct advantages over their constitutive synthesis. Two antimicrobial peptides from the skin secretions of frogs, MsrA2 (a derivative of dermaseptin B1) and temporin A, were evaluated for engineering pathogen-induced disease resistance in plants. Both peptides belong to a diverse group of small membrane-active molecules that are thought to be part of the innate defense system of their respective hosts against pathogen invasion. In vitro, synthetic MsrA2 and temporin A had strong antimicrobial activities against plant-specific pathogens, inhibiting germination of conidia and bacterial growth at low micromolar concentrations that were not toxic to plant protoplasts. As an approach to enhance plant resistance, the plant-optimized nucleotide sequences encoding MsrA2 and temporin A were transcriptionally fused to the inducible win3.12T poplar promoter, which had strong systemic activity in response to fungal infection, and introduced into tobacco (Nicotiana tabacum L. cv. Xanthi). Transgene expression was very low in leaves of unstressed plants; however, it was strongly increased after pathogen challenge or wounding. Upon induction, the amount of MsrA2 was up to 6-7 µg/g of fresh leaf tissue. Most importantly, the induced accumulation of MsrA2 and

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temporin A in transgenic tobacco was sufficient to confer resistance to a variety of phytopathogenic fungi, such as Fusarium solani, F. oxysporum, Alternaria alternata, Botrytis cinerea, Sclerotinia sclerotiorum, the oomycete Pythium aphanidermatum, and the bacterium Pectobacterium carotovorum. All transgenic plants were healthy and showed no morphological or developmental abnormalities even in the lines with the highest peptide accumulation. Thus, the expression of MsrA2 and temporin A in a pathogen-inducible manner enables the development of plants with wide-spectrum disease resistance, thereby reducing the use of pesticides in the environment and the associated health risks to humans. C2-6 Molecular biochemistry of conifer defense against insects: Formation of (+)-3-carene in Sitka spruce that are susceptible or resistant to attack by white pine weevil Dawn Hall, J Robert, CI Keeling, and J Bohlmann Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada dehall74@interchange.ubc.ca White pine weevil (Pissodes strobi) attacks several commercially important conifer hosts across North America including Sitka Spruce (Picea sitchensis). Oleoresin contains a complex mixture of monoterpenes, and has long been identified as an important defense mechanism in conifers. Monoterpenes are well-documented as toxins, deterrents or volatile chemical signals, and are implicated in the plant’s defense response to invading insects and pathogens. The profile of individual monoterpenes in oleoresin varies with the genotype of the tree, and these differences may impact the tree’s resistance. A comparison of the monoterpene profiles between a highly resistant and a highly susceptible genotype of Sitka spruce identified several differentially accumulating monoterpenes, including (+)-3-carene. An investigation into the genomic, molecular and biochemical mechanism of (+)-3-carene biosynthesis in resistant and susceptible Sitka spruce resulted in the cloning and functional characterization of a small family of terpenoid synthase genes encoding (+)-3-carene synthases and closely related (85-90% amino acid identity) sabinene synthases. Enzyme assays with native Sitka spruce protein reveal that the resistant chemotype is capable of producing high levels of (+)-3-carene following weevil attack, whereas only low levels of (+)-3-carene synthase activity are detected in the susceptible chemotype. Possible mechanisms underlying the absence of (+)-3-carene in susceptible Sitka spruce will be discussed. C2-7 The role of the Arabidopsis cyclic nucleotide-gated ion channels, AtCNGC11 and 12 in abiotic and biotic stress responses K Chin1,2, W Moeder1,2, S Mosher1,2, W Urquhart1,2, and Keiko Yoshioka1,2 1Dept of Cell and Systems Biology and 2Center for the Analysis of Genome Evolution and Function (CAGEF), University of Toronto, 25 Willcocks St, Toronto, ON, Canada, M5S 3B2 yoshioka@csb.utoornot.ca

Cyclic nucleotide-gated ion channels (CNGCs) are nonselective cation channels which were first discovered in retinal photoreceptors and olfactory sensory neurons. So far, six CNGC genes have been found in mammalian genomes and their important functional features were extensively studied. On the contrary, CNGCs are a relatively recent arrival as plant ion channels. In the Arabidopsis genome, a large family of CNGC genes, consisting of twenty members was identified by bioinformatics analyses. Considering that only six CNGC genes were found in mammalian genomes, the large size of this gene family in plants suggests diversity and importance in physiological functions of this gene family in plants. However, the biological role of each member has hardly been characterized yet. Previously, we have shown that ATCNGC11 and ATCNGC12 are involved in pathogen resistance responses and development of programmed cell death (Yoshioka et al., 2006, Urquhart et al., 2007). In this study, we focused on the role of ATCNGC11 and 12 in abiotic stress responses using T-DNA insertion knockout mutants and potential double mutants for both of these genes. The single knockout mutants for both genes showed enhanced tolerance to excess amounts of Ca2+ and K+, but not Na2+. However, in contrast the potential double knockout mutants showed enhanced sensitivity to these ion stresses, suggesting overcompensation for the lack of two CNGC genes. Furthermore, all mutants exhibited alterations their response to the phytohormone ABA, strongly suggesting a role of these genes in environmental stress responses. *Yoshioka et al. (2006) Plant Cell 18, 747-763, Urquhart et al .(2007)Plant Mol. Biol. 65, 747-761. C2-8 Compilation of a database of RNA profiles comparing susceptible and resistant wheat Infected with Fusarium graminearum Ouellet T, Hattori J, Gulden S, Zheng W, Rocheleau H, Wang L, Fedak G, Soleimani V, Singh J, Pandeya R, Somers D, and Tinker N 960 Carling Ave, room 2091, Ottawa, ON, Canada, K1A 0C6 ouellettr@agr.gc.ca Diseases caused by the fungus Fusarium graminearum constitute one of the major problems in cereal crops grown in temperate climates worldwide. Conventional breeding approaches have so far produced limited success in improving the resistance of crops, including wheat, to F. graminearum. A genomics approach is being applied to gain a better understanding of the wheat response to this fungus in susceptible and resistant varieties. Microarray hybridization experiments have been conducted using the wheat Affymetrix genome array, comparing mock-inoculated and Fusarium-inoculated spikelets from samples collected at 1, 2 and 4 days after inoculation. All profiles are being compiled into a database using the softwares Acuity and Access. So far, we have obtained the RNA profiles of four groups of wheat plants: 1) the spring wheat varieties Roblin (very susceptible), Wuhan 1 and Nuy Bay (both resistant, from Chinese and Japanese sources of resistance respectively); 2) the spring wheat Chinese Spring (susceptible) and the addition lines 7E and 7ES (both resistant, containing the chromosome 7 from Thinopyrum elongatum into Chinese Spring background); 3) the winter wheat Augusta

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(susceptible) and FHB148 (resistant, derived from Frontana, a Brazilian source of resistance); 4) near isogenic lines, derived from the cross Wuhan 1 x Nuy Bay, that segregate for the QTLs 2D, 3BS and 5A which are associated with Fusarium resistance. Preliminary findings of a meta-analysis of the data in the database will be presented.

Concurrent session 3: Photosynthesis Séance plénière 3 : Photosynthèse

C3-9 LHCSR is an ancient member of the light harvesting complex superfamily and it is required for photo-protection in Chlamydomonas reinhardtii Graham Peers1, T Truong1, D Elrad2, A Grossman2, and KK Niyogi1 1Dept of Plant and Microbial Biology, UC Berkeley; 2 Dept of Plant Biology, Carnegie Institute of Washington gpeers@nature.berkeley.edu Algae and plants can fine-tune the photosynthetic apparatus between a state that favours light harvesting and one that promotes the dissipation of absorbed light energy. Heterogeneity in the natural light environment requires rapid switching between these two states in order to maintain a high photosynthetic efficiency and to avoid photo-oxidative damage. We are investigating the diversity of mechanisms that plants and algae use to dissipate excess light energy. Chlamydomonas reinhardtii is a model green alga that thrives in a variety of light environments. When this alga is grown in light fluxes >350 µmol photons m-2 sec-1, their photoprotective capacity is induced (measured as the non-photochemical quenching of chlorophyll fluorescence, NPQ). The npq4 mutant is deficient in the rapidly reversible component of NPQ, and it is missing two of three LHCSR genes. LHCSR (formerly known as LI818) accumulates during growth in excess light. LHCSR mRNA is up regulated in response to physiological stress and its expression in different light conditions correlates with NPQ capacity. This protein is an ancient member of the LHC family of pigment-protein complexes that constitute the light-harvesting antennae of the photosystems. Homologs of this gene are found throughout the photosynthetic eukaryote taxa except red algae and higher plants. Additionally, we find that a homologue of LHCSR accumulates during high light stress in Ostreococcus, an emerging model prasinophyte alga. We will discuss the diversity and evolution of the photoprotective mechanisms that occur in plants and algae. C3-10 Characterization of a high non-photochemical quenching mutant of Chlamydomonas reinhardtii Lindsay L Gray and Kenneth E Wilson Dept of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, Canada, S7N 5E2 lindsay.gray@usask.ca The light harvesting complex (LHC) and its associated pigments absorb the majority of light energy required for photoautotrophic growth in photosynthetic eukaryotes. Structurally, the LHC is well characterized, but little is known about how individual LHC components are assembled.

Our research aims to identify protein factors required to produce a functional LHC by utilizing a Chlamydomonas reinhardtii line with a ∆psaF mutation. This mutation creates a buildup of electrons as they enter photosystem I and causes high-light sensitivity. Our hypothesis is that secondary mutations which lead to high-light survival may be the result of LHC assembly defects. Suppressor mutants were created by random insertional-mutagenesis of the ∆psaF line’s nuclear genome; the C50 line was selected for this investigation. The C50 line exhibits approximately wild type chlorophyll levels and chlorophyll a:b ratio, initially suggesting normal LHC assembly. However, Western blots indicate C50 has reduced LHCa levels and increased LHCb levels. Light-saturation curves indicate C50 has an increased capacity for heat dissipation and is able to limit damage caused by excess energy. Unfortunately, it appears the high non-photochemical quenching phenotype is not linked to our insertion, presenting challenges for identification of the responsible gene and we have chosen to investigate other cell lines. C3-11 Structure-function analysis of the Arabidopsis Toc159 family acidic-domains LGL Richardson1,2 and Matthew D Smith2 1University of Waterloo, Waterloo, ON, Canada, N2L 3G1; 2Wilfrid Laurier University, Waterloo, ON, Canada, N2L 3C5 msmith@wlu.ca Members of the Toc159 family of receptors are the primary chloroplast preprotein receptors in Arabidopsis. It has been suggested that the Toc159 receptors assemble, with either atToc33 or atToc34, into structurally distinct Toc complexes, which also demonstrate functional specificity; atToc159/33-containing complexes import photosynthetic proteins, while atToc132(120)/34-containing complexes import plastid house-keeping proteins. Most variability in primary structure between the Toc159 receptors occurs in the N-terminal A-domain, suggesting that this domain may contribute to the specificity of these receptors. To gain insight into A-domain function, the role of the A-domain in Toc159 receptor-targeting to structurally distinct Toc complexes was investigated using in vitro chloroplast targeting assays with chloroplasts isolated from wild-type plants, and atToc33 and atToc34 null mutants. Results suggest that the A-domain of atToc159 may play an important role in the regulation of insertion of this receptor into distinct Toc complexes, which is presumed to be essential for proper Toc complex function. Secondly, CD spectroscopy was used to examine the secondary structure of the Toc159 family A-domains, and their potential preprotein binding characteristics. Determining the structure of the Toc159 family A-domains will be important for understanding the molecular basis of protein-protein interactions between these receptors and their preprotein substrates. The most current structural data will be presented.

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C3-12 A multi-protein bicarbonate dehydration complex essential to carboxysome function in cyanobacteria S Cot, A So, and George Espie Dept of Biology, University of Toronto, Mississauga, ON, Canada george.espie@utoronto.ca Carboxysomes are proteinaceous biochemical compartments that constitute the enzymatic “back-end” of the cyanobacterial CO2-concentrating mechanism. These protein-bound organelles catalyze HCO3- dehydration and photosynthetic CO2 fixation. In Synechocystis sp. strain PCC6803 these reactions involve the β-class carbonic anhydrase (CA), CcaA, and Form 1B ribulose-1,5- bisphosphate carboxylase/oxygenase (Rubisco). The surrounding shell is thought to be composed of proteins encoded by the ccmKLMN operon, though little is known about how structural and catalytic proteins integrate to form a functional carboxysome. Using biochemical activity assays and molecular approaches we have identified a catalytic, multi-protein HCO3- dehydration complex (BDC) associated with the protein shell of Synechocystis carboxysomes. The complex was minimally composed of a CcmM73 trimer, CcaA dimer and CcmN. Larger native complexes also contained RbcL, RbcS and 2 or 3 immunologically-identified smaller forms of CcmM (62, 52 and 36 kDa). Yeast two-hybrid analyses indicated that the BDC was associated with the carboxysome shell through CcmM73-specific protein interactions with CcmK and CcmL. Protein interactions between CcmM73 and CcaA, CcmM73 and CcmN or CcmM73 and itself required the N-terminal γ-CA-like domain of CcmM73. The specificity of the CcmM73-CcaA interaction provided both a mechanism to integrate CcaA into the fabric of the carboxysome shell as well as a means of recruiting this enzyme to the BDC during carboxysome biogenesis. Functionally, CcaA was the catalytic core of the BDC. CcmM73 bound H14CO3- but was unable to catalyze HCO3- dehydration, suggesting that it may potentially regulate BDC activity. Mechanistically, we propose that this shell-localized complex controls a pathway for the entry of cytosolic HCO3- to the carboxysome interior where it is subsequently dehydrated to CO2 by CcaA and channeled to Rubisco for fixation.

Concurrent session 4: Plant development Séance parallèle 4 :

Développement des plantes C4-13 Arabidopsis ribosomal proteins RPL23aA and -B are disparately required for normal plant development Rory F Degenhardt and PC Bonham-Smith Dept of Biology, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5E2 rfd014@mail.usask.ca Protein synthesis is catalyzed by the ribosome, a two subunit enzyme comprised of four rRNAs and, in Arabidopsis (Arabidopsis thaliana), 81 ribosomal proteins (r-proteins). Plant r-protein genes exist as families of multiple

expressed members, yet only one r-protein from each family is incorporated into any given ribosome, suggesting that many r-protein genes may be functionally redundant or development/tissue/stress specific. Here we used RNA interference to characterize the gene silencing phenotypes of a large subunit r-protein family, RPL23a, containing two expressed genes (-A and -B). Independent knockdowns of endogenous RPL23aA and -B transcript levels determined that a RPL23aB knockdown did not alter plant growth or development. Conversely, a knockdown of RPL23aA produced a pleiotropic phenotype characterized by growth retardation, irregular leaf and root morphology, abnormal phyllotaxy and vasculature, and loss of apical dominance. Comparison to other mutants suggests that the phenotype results from reduced ribosome biogenesis, and we postulate a link between translational capacity, microRNA-target degradation and maintenance of auxin homeostasis. C4-14 Shoot regeneration in Arabidopsis Steven Chatfield, C Trobacher, M Tanimoto, J Greenwood, J Colasanti, and M Raizada University of Guelph, Guelph, ON, Canada, N1G 2W1 schatfie@uoguelph.ca, raizada@uoguelph.ca Regeneration via adventitious shoot apical meristems (SAMs), is widespread ability in the Plant Kingdom and this developmental flexibility has been successfully exploited by decades of in vitro culture. However, traditional tissue culture techniques typically rely upon high exogenous concentrations of auxin and cytokinin, and may take weeks to regenerate shoots from undifferentiated callus. Here we report, for the first time, adventitious shoot regeneration in the model plant Arabidopsis, without the need for exogenous hormones. New SAMs are induced in the hypocotyl and uppermost root, rapidly (4-10 days) by decapitation. The process involves the conversion of lateral root primordia (LRP) into new SAMs. Reporters for the SAM specific genes WUSCHEL (WUS) and CLAVATA3 (CLV3) are first expressed in organs with shared anatomical features of root and shoot meristems (48 hours post-decapitation). There is a functional requirement for the WUS gene in decapitation-induced shoot regeneration, but not CLV3. We have investigated the role of various hormones in the process and have been able to induce similar patterns of shoot regeneration and SAM reporter gene expression using sequential applications of physiological concentrations of auxin and cytokinin. Using this inducible system and confocal microscopy we have followed the loss of fluorescent root meristem (RAM) reporters and the up-regulation of SAM specific genes during the conversion of LRP to shoot meristems. We have found that expression root meristem/primordia specific markers and SAM specific reporters are mutually exclusive.

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C4-15 Time-lapse imaging of Arabidopsis leaf develop-ment shows dynamic patterns of procambium formation MG Sawchuk, P Head, TJ Donner, and E Scarpella Dept of Biological Sciences, University of Alberta, Edmonton, AB, Canada, T6G 2E9 msawchuk@ualberta.ca The principles underlying the formation of leaf veins have long intrigued developmental biologists. In leaf development, files of vein-forming procambial cells emerge from the seemingly homogeneous subepidermal tissue through the selection of anatomically inconspicuous preprocambial cells. Understanding the dynamics of procambium formation has been hampered by the difficulty of observing the process in vivo. Here, we present a live-imaging system that allows us to visualize complex processes in leaf development. We combined our method with new stage-specific fluorescent markers to visualize the dynamics of preprocambial strand formation and procambial differentiation during both normal and perturbed development. Under all experimental condi-tions, we observed extension, termination and fusion of preprocambial strands and simultaneous initiation of procambium differentiation along entire individual veins. Our findings strongly suggest that progressiveness of procambial strand formation and simultaneity of procambium differentiation represent inherent properties of the mechanism underlying vein formation. C4-16 The auxin response factor MONOPTEROS regulates leaf formation through multiple pathways M Schuetz1, T Berleth2, and Jim Mattsson1 1Dept of Biological Sciences, Simon Fraser University, BC; 2Cell and Systems Biology, University of Toronto, ON mattsson@sfu.ca Initiation of leaves at the flanks of the shoot apical meristem occurs at sites of auxin accumulation and pronounced expression of auxin-inducible PIN genes, suggesting a feedback loop to progressively focus auxin in concrete spots. Since PIN expression is regulated by Auxin Response Factor (ARF) activity, including MONOPTEROS (MP), it appeared possible that MP affects leaf formation as a positive regulator of PIN genes and auxin transport. Here we analyze a novel, completely leafless phenotype arising from simultaneous interference with both auxin signaling and auxin transport. We show that mp pin1 double mutants, as well as mp mutants treated with auxin-efflux inhibitors, display synergistic abnormalities, not seen in wild type regardless of how strongly auxin transport was reduced. In mp mutant background, auxin transport inhibition completely abolishes leaf formation. Instead of forming leaves, the abnormal shoot meristems dramatically increase in size harboring correspondingly enlarged ex-pression domains of CLAVATA3 and SHOOTMERISTEMLESS, molecular markers for the central stem cell zone and the complete meristem respectively. The observed synergism under conditions of auxin efflux inhibition was further supported by an unrestricted PIN1 expression in mp meristems, as compared to a partial restriction in wildtype meristems. Auxin transport-inhibited mp meristems also lacked detectable auxin maxima. The synergism of abnormalities indicates that the role of MP in shoot meristem organization is not limited to auxin transport regulation.

Concurrent session 5: Trace elements and phytoremediation

Séance parallèle 5 : Microéléments et phytoremédiation

C5-17 NSERC Update / Mise à jour du CRSNG Mario Lamarca 350 Albert Street, Ottawa, ON, Canada, K1A 1H5 mlamarca@nserc.ca Dr. Lamarca is Director of Life Sciences and Special Research Opportunities at the National Sciences and Engineering Research Council of Canada. Dr. Lamarca will provide an update on the International Review of the Discovery Grants Programs as well as the Grant Restructuring Project. C5-18 Characterization of a mutant strain of Chlamydomonas reinhardtii deficient in the molybdenum cofactor Fingrut DF, Li W, and Maxwell DP Dept of Biology, the University of Western Ontario, London, ON, Canada, N6A 5B7 dfingrut@uwo.ca Molybdenum is an essential micronutrient which is required as a redox-active cofactor in a diverse range of organisms representing all kingdoms. Molybdenum is biologically active only when complexed to a unique pterin compound forming the molybdenum cofactor (MoCo). This cofactor is required in plants and green algae for the activity of nitrate reductase, xanthine dehydrogenase, sulfite oxidase and aldehyde oxidase. In the green alga Chlamydomonas reinhardtii, mutants defective in MoCo biosynthesis can be selected on the basis of their inability to grow on media where nitrate is the sole nitrogen source as they lack activity of the enzyme nitrate reductase. One strain of Chlamydomonas that was mutated by random insertion of a bleomycin-resistance cassette is DB6, which is unable to assimilate nitrate and specifically lacks terminal nitrate reductase activity. It was determined that DB6 is deficient in the MoCo required for this activity as DB6 also lacked activity of xanthine dehydrogenase, another Molybdo-enzyme. In addition, the inability to grow on nitrate can be partially rescued in DB6 by growth on very high molybdate-containing media – a so-called ‘molybdate repairable’ phenotype. This finding suggests that the site of mutation in DB6 is either in molybdate transport or at the step of molybdenum insertion into the MoCo precursor molybdopterin. The insertional mutagen landed (putatively) within the 3’ untranslated region of a SULTR class sulfate transport gene. This class of gene has recently been shown to be involved in molybdate transport. This work may lead to the conclusive discovery of a new molybdate transport gene in Chlamydomonas reinhardtii.

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C5-19 Localization of aluminum in Eriophorum vaginatum leaves C Begy and E Cholewa Nipissing University, Dept of Biology, 100 College Drive, North Bay, ON, Canada, P1B 8L7 ewac@nipissingu.ca Aluminum is the most abundant metal in the earth’s crust, and its hydrolization is increased in low pH, nutrient deficient environments where Al3+ is a predominate form. Intensive mining in Sudbury, Ontario, has caused the acidification of soils, allowing toxic metals to be readily available for biological uptake. Eriophorum vaginatum is a perennial cotton-grass sedge that colonizes acidic, metal polluted wetlands in Sudbury. The ability to flourish in metal-contaminated wetlands without displaying toxic effects suggests E. vaginatum is resistant to pollutants. A previous study determined high levels of aluminum present in soils (14311ug/g), as well as in corms (59ug/g) of E. vaginatum collected from contaminated sites in the Sudbury region (Ontario, Canada). In this study, the patterns of aluminum localization in E. vaginatum leaves are investigated with the use of the Lumogallion probe and confocal microscopy. Aluminum was detected within the vascular bundles and the cell walls of epidermal tissues, suggesting that metal ions are transported from vascular tissues to the epidermis through lignified bundle sheath extensions via the apoplastic pathway. Accumulation in the cell wall indicates that E. vaginatum is capable of compartmentalizing aluminum, rendering it unable to interfere with cytoplasmic activities. Our results revealed that aluminum was accumulated in the waxy cuticle, where it could form ligands with negatively charged sites on hydrophobic lipids. In addition, a strong aluminum signal was detected in the vicinity of the guard cells, indicating that aluminum is deposited there via the transpiration stream. This research indicates the possible use of E. vaginatum in the revegetation of disturbed peat lands and the biostabilization of flooded mine tailings. C5-20 Dynamics of mycorrhizal symbiosis & heavy metal phytoremediation: From meta-analytical modeling to in vitro analysis Patrick Audet and Ch Charest Dept of Biology, University of Ottawa, 30 Marie Curie St, Ottawa, ON, Canada, K1N 6N5 paude086@uottawa.ca The arbuscular mycorrhizal (AM) symbiosis - an association between the roots of most herbaceous plants and Glomeromycota fungi - is a key component of ecosystem function particularly regarding its involvement in plant resource acquisition and nutrient cycling. This association is recognized for benefiting host plants subjected to environmentally-stressful conditions (e.g. nutrient deficien-cy & drought), and has recently been shown to play an important role in the removal of heavy metal (HM) contaminants through a process of phytoremediation. By using meta-analytical modeling and in vitro carrot root-organ culture, we investigated HM phytoremediation processes and the inherent role of AM symbiosis as a key factor of plant growth and metal-stress tolerance. We determined that AM fungi benefit plants dynamically by

(1) enhancing metal uptake under low (trace) HM conditions, and (2) decreasing uptake via metal-binding under high (toxic) HM conditions thereby enhancing plant growth. In addition, we propose that plants may invest in mycorrhizal symbiosis in an extrinsic stress avoidance strategy, complementing other intrinsic stress resistance mechanisms, to circumvent the effects of HM toxicity.

Concurrent session 6:

Teaching and education; Employment and training

Séance parallèle 6 : Enseignement et éducation ;

Emploi et formation C6-21 IT as the missing lab partner in undergraduate biology Jon G Houseman, Professor and 3M National Teaching Fellow Biology, University of Ottawa In 2004 the Biology Department moved into its new undergraduate teaching facilities which include 10 labs with a capacity for 392 students. What makes these new state-of-the-art labs unique is each of the 196 workstations is a combination of wet bench and microscopy station found in the traditional bio lab and a computing workstation. Students work in pairs with a compound and dissecting microscope, each with a digital camera connected to the workstation’s computer; a part of the undergraduate science computing network. Each lab has a central podium where the instructor can monitor what students have on their screen, override the workstation computers and present material to the whole lab or showcase individual student work on the computer screens in the room. Each lab is equipped with a digital video camera and audio link and for large courses with simultaneous lab sections the instructor can broadcast into all labs simultaneously. In this presentation I take a look at the history of the project implementing information technologies and student reactions to the new facilities. As well I take a look at how the presence of the computer and instructional technologies at the work bench has changed the dynamics of the interaction between student pairs and as well, the demonstrators and instructor’s during a lab session. I’ll also explain how the facilities have allowed us to create a unified on-line support system for our undergraduate labs. C6-22 Using case studies to promote learning, collaborations, and critical thinking in large classes Colin Montpetit Dept of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada, K1N 6N5 colin.montpetit@uottawa.ca The potential to support and promote active learning and critical thinking with case study teaching methods is widely recognized in the literature. Educators reason that the engagement characteristics of such teaching and active

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learning activities can provide powerful learning tools if properly exploited. Despite its successes in improving student performance (i.e. information retention, analysis, communication, etc.) integrating these types of teaching and learning innovations into large classes and existing classroom based programs have been challenging. Many remain skeptical about using them due in large part to real and perceived barriers (i.e. faculty, student, and colleague/administrative barriers). The goal of this presentation is to give perspectives of challenges and efforts to offer engaging lectures in which students are active participants in large enrolment courses. While the case method teaching method cannot solve all of the challenges in the teaching of science, the method is ideal to develop higher–order reasoning skills. When used within large enrolment courses, even occasionally, they spice up the semester, increase student interest in the subject matter and improve student performance on exams. C6-23 Keystones for a successful scientific career in ag-biotechnology industry Jiangxin Wan 700 Gardiners Road, Kingston, ON, Canada, K7M 3X9 wanj@performanceplants.com A research career in industry is often considered to be less intense and stressful than one in academia. This is, of course, a misconception as scientists working in industry are facing an increasing amount of challenges arising from both scientific and commercial fronts. To survive a corporate culture and excel as a research scientist, one needs to possess several key characteristics including being innovative and knowledgeable, focused and goal driven, and flexible and collaborative. Even though these appear to be the common attributes found in scientists working in the academic world, there are subtle but distinct differences between the careers. The key elements for developing or adapting a successful and productive career in ag-biotech industry will be shared here, together with the experiences and lessons picked up along the way. C6-24 Protecting Canada's biodiversity: Careers in risk assessment at the Canadian Food Inspection Agency Phil Macdonald 159 Cleopatra Drive, Ottawa, ON, Canada, K1A 0Y9 pmacdonald@inspection.gc.ca Science graduates have traditionally thought of careers in science in terms of working directly in a research laboratory, conducting applied science in an industry setting or occasionally teaching science to others. Regulatory science and careers in regulatory science are not often on the radar of job seeking graduates despite the fact that there are many exciting and useful career options in this area where a graduate can directly apply knowledge gained in their field of study. The Canadian Food Inspection Agency is Canada’s largest science based regulatory agency. We are dedicated to safeguarding food, animals and plants. Protecting biodiversity is one of the Agency’s key roles. Timely accurate assessments of risk that incorporate all

considerations including climate change are critical for carrying out this vital role. The Agency is actively seeking young scientists who want to make a difference in the lives of Canadians and are interested in pursuing careers in public service.

Concurrent session 7: Abiotic stress Séance parallèle 7: Stress abiotique

C7-25 Development of drought tolerant plants through molecular tailoring of ABA sensing Yafan Huang*, J Ying*, M Kuzma*, M Beaith*, Y Wang*, M Chalifoux*, A Sample*, C McArthur*, T Uchacz*, C Sarvas*, D T Dennis*, J Northey†, P McCourt†, and J Wan* *Performance Plants Inc, 700 Gardiners Road, Kingston, ON, Canada, K7M 3X9; †Dept of Cell & Systems Biology, University of Toronto, 25 Willcocks St, Toronto, ON, Canada, M5S 3B2 huangy@performanceplants.com Drought is the most significant negative factor for plant’s productivity and maintaining crop yield under drought stress is a top priority for modern agriculture. As an innate response to water deficit, the cellular level of phytohormone abscisic acid (ABA) is rapidly increased, triggering closure of stomates and direct reduction of transpirational water loss. This suggests that genetic manipulation of the stress response to ABA should be a promising approach for improving plant drought tolerance. Previous genetic studies in Arabidopsis and other plants have revealed key components in the pathways for ABA biosynthesis and signaling, and several of which are implicated in regulation of water stress tolerance. Here we show that molecular manipulation of protein farnesylation in Arabidopsis, through down-regulation of either the α or β subunit of farnesyltransferase, enhances the plant’s sensitivity to ABA and drought tolerance. The effectiveness of these ABA sensing genes for drought tolerance and yield protection is confirmed in canola in the field conditions through multiple years and multiple locations of field trials. These results were achieved with transgenic Brassica napus carrying down-regulation constructs of either the α or β subunit of farnesyltransferase driven by specific sets of promoters. Currently we are extending our molecular and physiological analysis to other components in the farnesylation pathway. Using protein farnesyltransferase as an effective target, we have also made significant progresses on engineering drought tolerance in other important crop species.

C7-26 The purple acid phosphatase AtPAP26 is required for efficient acclimation of Arabidopsis thaliana to nutritional phosphate starvation Brenden A Hurley and WC Plaxton Dept of Biology, Queen’s University, Kingston, ON, Canada, K7L 3N6 3bh4@queensu.ca Agricultural phosphate (Pi) deficiency is alleviated by the massive, but inefficient and unsustainable application of Pi fertilizers. The projected depletion of global rock-Pi reserves by 2100 has prompted scientists to develop strategies for

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engineering Pi-efficient crops. This necessitates a thorough understanding of the intricate adaptations of Pi-starved (-Pi) plants which include the de novo synthesis of purple acid phosphatases (PAPs). –Pi plants are believed to employ PAPs to scavenge Pi from a wide range of intracellular and extracellular (soil) P-esters. We recently identified AtPAP26 (encoded by At5g34850, 1of 29 putative Arabidopsis PAP genes) as the predominant intracellular and secreted PAP upregulated by –Pi Arabidopsis (2006 Plant Physiol 142:1282; Tran & Plaxton, this meeting). To test the hypothesis that AtPAP26 is pivotal to Pi scavenging by -Pi Arabidopsis, the phenotypic, biochemical, and molecular features of loss-of-function Arabidopsis mutants are being assessed. Two independent homozygous T-DNA insertional mutants for AtPAP26 were established by their germination on selective media, followed by PCR verification of T-DNA insert location. AtPAP26 transcripts and immunoreactive AtPAP26 polypeptides were either undetectable or greatly reduced in AtPAP26 knockout plants which uniformly: (1) failed to upregulate APase activity following Pi-deprivation, and (2) demonstrated markedly impaired growth (relative to Col-0 wild-type) when cultivated under –Pi, but not Pi-sufficient conditions. These results support a key function for AtPAP26 in Pi scavenging and acquisition by –Pi Arabidopsis. C7-27 Expression of wheat VERNALIZATION 2, TaVRN2 delays flowering and enhances freezing tolerance in Arabidopsis Diallo AO, Kane NA, Agharbaoui Z, Badawi M, and F Sarhan Dép des sciences biologiques, Université du Québec à Montréal, CP 8888 Succ Centre-ville, Montréal, QC, Canada, H3C 3P8 ouryba@hotmail.com TaVRN2 is a major flowering repressor in temperate cereals that is regulated by low temperature and photoperiod. We show here, that the gene is also regulated by salt, heat shock, dehydration, wounding and ABA. Promoter analysis indicates the TaVRN2 promoter posses all the specific responsive elements to these stresses. This suggests pleiotropic effects of TaVRN2 in wheat development and adaptability to environment. To determine if TaVRN2 also act as flowering repressor in other species, the gene was ectopically expressed in the flowering model plant Arabidopsis. Transgenic plants showed no alteration in morphology, but their flowering time was delayed compared to controls plants, confirming that TaVRN2, although having no ortholog in Brassicaceae, can act as a flowering repressor outside the cereals group. In addition transgenic plants showed enhanced freezing tolerance. This increase in tolerance was due to the accumulation of the activators CBF2 and CBF3 and the COR genes 15.a and 78. Taken together, our data demonstrate that TaVRN2 could be used to manipulate flowering time and enhance freezing tolerance in other species.

C7-28 Somatic and transgenerational response to stress in Arabidopsis and tobacco Alicja Ziemienowicz, V Titov, A Boyko, and I Kovalchuk Dept of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, AB, Canada, T1K 3M4 alicja.ziemienowicz@uleth.ca Plants are capable of rapidly reprogramming patterns of gene expression, allowing fast acclimation and adaptation in response to specific environmental conditions. Using transgenic Arabidopsis (Arabidopsis thaliana) or tobacco (Nicotiana tabacum) plants that allow the analysis of homologous recombination frequency we found that stresses such as heavy metals (Ni2+, Cd2+), NaCl, water stress and viral infection result in dramatic changes in recombination frequency as well as in the physiological response of the progeny to the same or different stresses. Specifically, the progeny (S1) of these plants exhibited higher spontaneous recombination frequency, changes in global genome methylation and higher tolerance to the same stress and to methyl methane sulfonate (MMS). The subsequent generation(s) of plant exhibited a different pattern; the changes persisted when the first generation was also grown in the presence of stress (S2, S3, S4 etc.), and the changes substantially decreased, albeit not to control levels, when it was grown at normal conditions (S1_Ct1, S2_Ct1 etc.). These changes suggest the involvement of the signal, possibly of epigenetic nature. To test the epigenetic basis of this phenomenon we have crossed our recombination reporter lines to Arabidopsis Dicer and RDRP mutants impaired in establishment/ maintenance of methylation. We found several Dicer mutants to have lower somatic recombination frequency. Knowing that Dicers are involved in production of small RNAs, one can suggest that DNA damage response and perhaps stress response requires production of small RNAs that possibly establish new pattern of genome methylation and chromatin structure. This allows differential gene expression in the progeny leading to higher tolerance to stress. To summarize, here we report that stressed plants inherit the memory of stress and that the exposure to stress has to be persistent in order to maintain the same level of adaptive response.

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Concurrent session 8: Secondary metabolism and

biotechnological applications Séance plénière 8 :

Métabolisme secondaire et applications biotechnologiques

C8-29 Structure-activity relationship of a wheat flavone o-methyltransferase J-M Zhou1, Francesca Kanapathy1, Y Lim2, and R Ibrahim1*

1Plant Biochemistry Lab, Concordia University, Montréal, QC, Canada, H4B 1R6; 2BioMolecular Informatics Centre, Konkuk University, Seoul 143-701, S Korea *ragibra@alcor.concordia.ca The wheat (Triticum aestivum L.) dimeric O-methyltransferase TaOMT2, catalyzes the sequential methylation of the flavone, tricetin to its monomethyl- (selgin), dimethyl- (tricin) and trimethyl derivatives, although tricin seems to be the major enzyme reaction product. The aim of this work was (1) to investigate the dimeric nature of the protein, using a mild chaotropic agent and analytical ultracentrifugation, and whether the dimer is necessary for catalytic activity; and (2) to gain an insight into the mechanism of sequential methylation of tricetin by molecular modeling of TaOMT2 using the highly similar (78% similarity, 63% identity) Medicago sativa caffeic acid/5-hydroxyferulic acid MsCOMT 3-D structure as a template. The results indicate that the dissociated monomers are both active and capable of catalyzing the sequential methylation of tricetin with the same efficiency as the homodimer. Homology modeling experiments reveal the formation of H-bonds within 1.6-2.4 Å of a number of aminio acid residues common to the three flavonoid substrates, suggesting the existence of one binding pocket, and their importance in substrate binding was verified by site-directed mutagenesis. Further work aims at determining the amino acid residues involved in catalysis and specifying those implicated in each step of the methylation sequence. C8-30 Towards an understanding of the non-darkening trait in cranberry bean (Phaseolus vulgaris) seed coats L Wright, T Smith, and K Peter Pauls Dept of Plant Agriculture, University of Guelph, Guelph, ON, Canada, N1G 2W1 ppauls@uoguelph.ca Age-darkened cranberry beans are discounted in the market because consumers associate darkening with increased cooking time and reduced palatability. Seed coat pigments are flavonoids synthesized by the phenylpropanoid pathway. The objectives of the proposed project are to screen cranberry bean germplasm to identify material that is significantly slower darkening and to study slow-darkening germplasm to understand the molecular basis for the trait. The material and the information could be used in the future to develop slow-darkening cranberry beans with increased market quality.

Seeds from approximately 700 cranberry-type lines obtained from the USDA National Germplasm system and our breeding program were subjected to an accelerated bean darkening protocol using germicidal UV lamps. Darkening was evaluated by eye and with a colourimeter. Most beans were found to darken but one very pale cranberry-like bean [Witrood boontje (PI439540)] was found to darken significantly less than any other. Crosses were made between the cranberry lines Etna and Capri and the non-darkening Witrood, as well as between Witrood and a non-darkening pinto line 1533-15. The F1 and F2 seeds were selected for cranberry or pinto types and selfed to obtain F3 seed, which was UV-screened for the non-darkening trait. This work resulted in the identification of several non-darkening lines with cranberry markings that are less intense than those of a typical cranberry bean but more pronounced than those of the previously identified non-darkening Witrood. Additionally, a cross between the slow-darkening 1533-15 pinto and Witrood yielded pinto beans that are virtually non-darkening. These results suggest that the strong non-darkening background of Wit-rood can be successfully incorporated into our patterned bean germplasm. Gene expression studies by Real-time PCR of several stages of developing bean seeds indicated that RNA synthesis for the phenylpropanoid genes occurs as early as a few days after pollination in these seeds. The presence of phenolic compounds (that are responsible for darkening) was confirmed by exposing immature seeds at various stages to UV. Seeds as young as a few days after pollination (5mm in length) darkened. Several differences in gene-expression within the phenylpropanoid pathway were measured by real-time PCR between developing seeds of the normal-darkening cranberry Hooter and the non-darkening cranberry-like Witrood. C8-31 Genomic analysis of 4CL-like ACYL-CoA SYNTHETASE genes reveals a novel pathway required for pollen wall formation Carl J Douglas, C Azevedo de Souza, S Kim, M Friedmann, S McKim, and G Haughn Dept of Botany, University of British Columbia, Vancouver, BC, Canada cdouglas@interchange.ubc.ca The pollen wall represents one of the most complex plant cell walls, with contributions from both the sporophyte and gametophyte generations. Formation of the pollen wall requires the deposition of a pecto-cellulosic wall (intine), a mixed aliphatic/aromatic polymer with ester and ether linkages (sporopollenin), and a lipid-rich coat. Many genes of unknown specific function have been annotated in plant genome sequencing projects, and many of these may encode undiscovered enzymes in plant metabolism and secondary metabolism. 4-coumarate:CoA ligase (4CL) plays a key role in lignin and other polyphenolic metabolite biosynthesis, generating activated CoA esters of hydroxycinnamic acids that are used as substrates for specific downstream pathways. Using an in silico similarity search based on the amino-acid sequences of known Arabidopsis genes encoding 4CL, we identified twelve 4CL-related genes that are members of an Arabidopsis acyl-CoA synthetase (ACS) gene family. We also identified all members of this ACS gene family in the fully sequenced

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poplar, rice, and Physcomitrella genomes. Phylogenetic analysis of members of the 4CL-like ACS gene family revealed an ACS subclade closely related to true 4CLs that contains a single gene from each of the four genomes investigated, as well as genes from other plants. Experimental and in silico expression analyses revealed that Arabidopsis and poplar members of this clade (AtACS5 and PoptrACS13) are flower and anther-preferred in expression, and these genes were chosen for functional analysis. AtACS5 is transiently and exclusively expressed in tapetum cells in the anther, with maximal expression just after release of microspores from tetrads in concert with the onset of sporopollenin deposition, suggesting a potential role in pollen wall and/or sporopollenin formation. Expression of PoptrACS13 is male flower preferred. An acs5 T-DNA insertion mutant is completely male sterile, fails to produce pollen grains, and pollen grains arrested in development are apparently devoid of sporopollenin. These data suggest that AtASC5 and similar enzymes from other species produce CoA ester intermediates used in an ancient pathway required for sporopollenin monomer biosynthesis. In silico co-expression analysis in Arabidopsis identified genes encoding other potential enzymes and transporters in this pathway, and related genes were found in poplar, rice, Physcomitrella, and other plants. Reverse genetic analysis of selected co-expressed genes revealed that mutants in these genes are also compromised in male fertility and sporopollenin deposition. Thus, a combination of genomic, functional genomic, and bioinformatics analyses has illuminated the outlines of a novel biosynthetic pathway likely involved in generating constituents of the sporopollenin component of the pollen wall. Hypotheses regarding nature of this putative pathway will be discussed. C8-32 Metabolism of the folate precursor p-aminobenzoate in plants: Glucose ester formation and vacuolar storage Gale G Bozzo1, A Eudes1, JC Waller1, V Naponelli2, E-K Lim3, DJ Bowles3, JF Gregory III2, and AD Hanson1 1Horticultural Sciences and 2Food Science and Human Nutrition Depts, University of Florida, Gainesville, FL 32611, and the 3Centre for Novel Agricultural Products, Dept of Biology, University of York, York, YO10 5DD, UK gbozzo@uoguelph.ca Plants produce p-aminobenzoate (pABA) in chloroplasts and use it for folate synthesis in mitochondria. In plant tissues, however, pABA is known to occur predominantly as its glucose ester (pABA-Glc), and the role of this metabolite in folate synthesis has not been defined. In this study, the UDP-glucose:pABA acyl-glucosyltransferase (pAGT) activity in Arabidopsis extracts was found to reside principally (95%) in one isoform with an apparent Km for pABA of 0.12 mM. Screening of recombinant Arabidopsis UDP-glucosyltrans-ferases identified only three that recognized pABA. One of these (UGT75B1) exhibited a far higher kcat/Km value than the others and a far lower apparent Km for pABA (0.12 mM), suggesting its identity with the principal enzyme in vivo. Supporting this possibility, ablation of UGT75B1 reduced extractable pAGT activity by 95%, in-vivo [14C]-pABA glucosylation by 77%, and the endogenous pABA-Glc/pABA ratio by 9-fold. The Keq for the pABA esterification reaction was found to be 3 × 10-3. Taken with literature

data on the cytosolic location of pAGT activity and on cytosolic UDP-glucose/UDP ratios, this Keq value allowed estimation that only 4% of cytosolic pABA is esterified. That pABA-Glc predominates in planta therefore implies that it is sequestered away from the cytosol and, consistent with this possibility, vacuoles isolated from [14C]pABA-fed pea leaves were estimated to contain ≥88% of the [14C]pABA-Glc formed. In total, these data and the fact that isolated mitochondria did not take up [3H]pABA-Glc, suggest that the glucose ester represents a storage form of pABA that does not contribute directly to folate synthesis.

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Poster Session Séance d’affiches

P-1 Differential accumulation of cadmium in durum wheat: roles of low molecular weight acids BA Adeniji, MA Bernards, and SM Macfie Dept of Biology, the University of Western Ontario, London, ON, Canada, N6A 5B7 badeniji@uwo.ca Cadmium readily accumulates in plants and can affect human health due to its neurotoxic, mutagenic and carcinogenic effects. To better understand the mechanisms of uptake and distribution of cadmium in plants, two pairs of isolines of durum wheat (Triticum turgidum var durum) were studied. Each pair can be distinguished into ‘high’ and ‘low’ accumulating isolines; the ‘high accumulating’ isoline typically translocates twice as much cadmium into the leaves and grain as compared to the ‘low accumulating’ isoline. We used a two-fold approach to decipher the mechanism(s) behind differential accumulation of cadmium: (1) the relative proportions of cadmium in the apoplast and symplast in the root tissues were measured to test the hypothesis that differential retention of cadmium in the root is related to partitioning of cadmium between the apoplast and symplast and (2) the types and concentrations of organic acids in the root exudates and plant tissues were measured to elucidate the putative roles of organic acids as chelators. Reduced translocation of cadmium to the leaves in the low accumulating isolines was associated with increased retention of cadmium in the symplast of the roots and with higher concentrations of fumaric acid in the roots and shoots. Concentrations of citric, malic, oxalic and succinic acids did not correlate with differential Cd accumulation between the two isolines. A definitive answer on the role of organic acid in differential cadmium translocation is not clear. P-2 Tomato gamma-glutamyl hydrolases – Expression, biochemical characterization and evidence for heterodimer formation Tariq A Akhtar, RP McQuinn, V Naponelli, JF Gregory III, JJ Giovannoni, and AD Hanson Horticultural Sciences Dept (TAA, ADH) and Food Science and Human Nutrition Dept (VN, JFG), University of Florida, Gainesville, FL 32611; United States Dept of Agriculture - Agricultural Research Service and Boyce Thompson Institute for Plant Research, Cornell campus, Ithaca, NY 14853 (RPM, JJG), USA takhtar@ufl.edu Folates typically have γ-linked polyglutamyl tails that make them better enzyme substrates, and worse transport substrates, than the unglutamylated forms. The tail can be shortened or removed by the vacuolar enzyme γ-glutamyl hydrolase (GGH). It is known that GGH is active as a dimer and thatplants can have several GGH genes whose homo-dimeric products differ functionally. However, it is not known whether GGH dimers dissociate under in-vivo

conditions, whether heterodimers form, or how heterodimerization impacts enzyme activity. These issues were explored using the GGH system of tomato (Solanum lycopersicum). Tomato has three GGH genes that, like those in other eudicots, apparently diverged recently. LeGGH1 and LeGGH2 are expressed in fruit and all other organs whereas LeGGH3 is expressed mainly in flower buds. LeGGH1 and LeGGH2 homodimers differ in bond cleavage preference; the LeGGH3 homodimer is catalyt-ically inactive. Homodimers did not dissociate in physiological conditions. When co-expressed in Escherichia coli, LeGGH1 and LeGGH2 formed heterodimers with an intermediate bond cleavage preference, while LeGGH3 formed heterodimers with LeGGH1 or LeGGH2 that had half the activity of the matching homodimer. The formation of LeGGH1-LeGGH2 heterodimers was demonstrated in planta using bimolecular fluorescence complementation. Plant GGH heterodimers thus appear to form wherever diff-erent GGH genes are expressed simultaneously, and to have catalytic characteristics midway between those of the corresponding homodimers. P-3 Isolation and characterization of Arabidopsis Will Die Slowly 2 (WDS2) during plant senescence and disease resistance Adel Al-Shammari, Owen Rowland, and Tim Xing Dept. of Biology and Institute of Biochemistry, Carleton University, Ottawa, ON, Canada, K1S 5B6 aashamma@connect.carleton.ca Programmed cell death (PCD) is a physiological process that involves the selective elimination of unwanted cells. PCD plays an important role in cell and tissue homeostasis, cellular differentiation, tissue sculpting, and disease resistance. Senescence, as one visible form of cell death, is a complex process and a highly regulated morphological stage in the life of a leaf. Senescence results in chlorophyll breakdown, RNA and protein degradation, and translocation of nitrogen, carbon nutrients, and minerals from the senescing leaf to other parts of the plants, and eventually cell death. The application of physiological and molecular biological methods to the study of leaf senescence has enabled the isolation and characterization of a large range of senescence associated genes (SAG) that have shown increased expression in senescing leaves. Studies of these genes and identification of the function of the encoded proteins have given further insights into the complex processes that take place during senescence. The combined action of several abiotic and biotic factors may be involved in the induction of senescence. Experiments with SAG transgenic plants and mutants have also indicated the role of cytokinins, ethylene and salicylic acid in the regulation of leaf senescence. We have identified a novel gene family, named Will Die Slowly (WDS), consisting of five members, WDS1-5. Our aim is to understand the molecular nature of the Will Die Slowly2 (WDS2) gene and the mechanisms that control leaf senescence. My hypothesis is that Will Die Slowly 2 (WDS2) has an important role in leaf senescence, plant development and disease resistance. The goal of this research is to build up a genetic role of WDS2 gene by cloning and characterizing the function of WDS2 gene in leaf senescence, salicylic acid signaling pathway and/or Fumonisin B1 (used as a pathogen elicitor)-induced cell

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death. The Drosophila melanogaster homolog has been implicated in cell death and it provides a rationale for testing the role of Arabidopsis WDS2. We have identified that wds2 regulate leaf senescence and also the gene expression is increased during senescence. P-4 Aquaporin gene expression in poplar trees: differential expression between tissues and in response to drought stress Adriana Almeida Rodriguez1, J Cooke2, F Yeh3, and J Zwiazek1 1442-Earth Sciences Bldg, 2CW460- Biological Sciences Bldg, 3701-General Services Bldg, University of Alberta, Edmonton, AB, Canada, T6G 2E1 adriana@ualberta.ca, Janice.Cooke@ualberta.ca, Francis.Yeh@ualberta.ca, Janusz.Zwiazek@ualberta.ca Aquaporins mediate the transmembrane movement of water and small solutes like glycerol and urea. In plants, these proteins are divided into four subfamilies including the plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), nodulin-like intrinsic proteins (NIPs), and simple intrinsic proteins (SIPs). Several studies have implicated root aquaporins in drought responses in plants and demonstrated changes in their abundance that was linked to changes in water transport properties. However, little is known about their abundance and role of aquaporins in other tissues, particularly under drought conditions. In the present study, the gene expression patterns of eleven different aquaporin genes was characterized using qRT-PCR by means of a standard curve method for relative quantification in three different poplar clones. H11-11 (Populus trichocarpa Torr. & Gray × Populus deltoides Marsh) was selected to determine the transcript abundance corresponding to these genes in four different tissues. In addition, Populus balsamifera and P38P38 hybrid poplar (P. simonii x P. balsamifera), which show contrasting drought resistance characteristics (drought avoidant and drought tolerant, respectively), were used for a drought experiment in which gene expression patterns were compared in leaves. The results showed that of the eight PIPs that were examined, four were mainly expressed in the secondary xylem, two in mature leaves, one in roots, and one in the secondary phloem. The two TIPs were mainly expressed in secondary phloem, and the SIP was mainly expressed in mature leaves. These findings show that even though the PIP subfamily is highly conserved in plants, aquaporins of this subfamily are differentially expressed between different plant tissues, likely reflecting their different roles in the maintenance of water status in different organs and tissues, as well as in the developmental stage of the tissues. These aquaporins were also differentially expressed between the two poplar clones exposed to drought conditions. In response to drought, six PIPs and one TIP increased their expression in response to mild and severe drought stress in P38P38, while balsam poplar showed little change in the expression of these genes. The putative PIP2.5 aquaporin was highly expressed in roots of H11-11, and also it was highly express in balsam poplar leaves in response to severe drought stress and during recovery from drought. Two PIP2 aquaporins - putative aquaporins 2.1 and 2.2 - increase their expression levels in both poplar clones even though their expression in unstressed plants

was higher in P38P38 hybrid poplar. Our findings suggest that aquaporins play distinct roles in different drought resistance strategies in poplars. P-5 Purification and characterization of extracellular glycosidases from the ginseng root pathogen, Pythium irregulare M Andreea Neculai and MA Bernards University of Western Ontario, 1151 Richmond St N, London, ON, Canada, N6A 5B7 mcostea@uwo.ca, bernards@uwo.ca Oomycetes are fungus-like organisms, represented worldwide and highly pathogenic to plants. Many of the species attacked by these organisms are economically important for humans (e.g. crops, vegetables and medicinal plants) and suffer great losses due to diseases caused by oomycetes. One such medicinal plant is American ginseng (Panax quinquefolius) known for its adaptogen, immunomodulatory and stimulant properties. Because native stands have declined, much of the commercially available ginseng is cultured; however, ginseng growers have encountered a significant threat in the oomycete Pythium irregulare, the causal agent of seedling damping off and root rot of ginseng plants. The mechanism of pathogenicity used by P. irregulare is not yet deciphered, but it is known that via extracellular glycosidases, this species is able to selectively metabolize the main 20(S) protopanaxadiol ginsenosides (i.e. the bioactive triterpenoid saponin compounds of ginseng). As shown for some true fungi (Gaeumanomyces graminis var. avenae, Septoria lycopersici and others), glycosidases can be involved in pathogenicity, being able to detoxify antifungal plant saponins. In order to find out if Pythium is using similar strategies and if these ginsenoside-metabolizing enzymes are involved in pathogenicity, the first step is to purify and characterize them. Therefore, the goal of this research project is to develop a chromatographic purification protocol yielding purified glycosidases from culture medium of P. irregulare and then characterize the enzymes. P-6 Evaluation of soybean protein for manufacturing industrial fibres and films Muhammad Arif and PK Pauls Dept of Plant Agriculture, University of Guelph, ON, Canada, N1G 2W1 marif@uoguelph.ca, ppauls@uoguelph.ca Recently, discussions about the preservation of natural resources and recycling have led to renewed interest in biomaterials with focus on renewable raw materials. Proteins are biopolymers with diverse molecular structures with an enormous range of functional and structural properties. Soybeans proteins have been reported to be appropriate materials for the production of fibres and films. The hypothesis that is being tested in the current study is that the different compositions that exist in seed storage proteins of different soybean genotypes will affect the functional properties of fibres and films produced from them. The objectives are to analyze selected soybean genotypes for their protein compositions and to produce fibres and films from them and test their properties. Soy

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protein isolates from sixteen soybean genotypes showed significant differences in protein composition as analyzed by sodium dodecyl sulfate polyacrylimide gel electrophoresis on the basis of protein band presence/absence, protein band intensities and percent protein. Seven genotypes with distinct protein compositions (including: Harovinton, OAC Huron, OAC Champion, OAC Bayfield, OAC Ayton, OAC Brussels and RIL 5) were selected for the production of protein fibres and films. Fibres and films produced from different protein isolates will be tested for morphology, strength, elasticity, heat and cold resistance, water and gas permeability and biodegradation by atomic force microscopy (AFM), scanning electron microscopy (SEM), tensile, dynamic-mechanical thermal analyses and Fourier Transform Infrared microscopy (FTIM). The functional properties of the fibres and films will be correlated with their protein compositions to identify components that are beneficial for industrial uses. P-7 Role of plastid-to-nucleus signaling in response of key steps of tetrapyrrole biosynthesis to light and cytokinin Natalia Averina, E Gritskevitch, and E Yaronskaya Institute of Biophysics and Cell Engineering of National Academy of Sciences of Belarus, Academicheskaya str 27, Minsk 220072, Belarus fezang@tut.by, averina@biobel.bas-net.by There are some biochemical and genetic evidences that plastids produce signals that participate in plastid-to-nucleus crosstalk controling an expression of nuclear genes encoding a set of chloroplast proteins. Generation of one of the plastid signals, the molecular nature of which is absolutely unknown, is connected with functioning of chloroplast protein synthesis system. The effect of this signal on expression of nuclear genes encoding enzymes of tetrapyrrole biosynthesis and its interaction with signal chains triggered by some exogenous stimuli such as light and cytokinins are little investigated. We have studied the influence of plastid ribosome deficiency generated by a short exposure of barley seeds to streptomycin, the inhibitor of plastid translation, on key reactions of tetrapyrrole biosynthesis and response of albino seedlings, grown from these seeds, to light and cytokinin. Chlorophyll (Chl) content in seedlings of albino phenotype was 0.1% of that in control plants untreated with streptomycin. Very low content of protochlorophyllide in etiolated plants (3-4% of control) is evidence that activity of Chl biosynthesis is dependent on the level of plastid protein synthesis in absence of the light. Ribosome deficiency in etiolated, greening and green leaves results in practically complete inhibition of capacity to synthesize 5-aminolevulinic acid destined to Chl biosynthesis but not for heme formation. Neither light nor kinetin stimulate 5-aminolevulinic acid biosynthesis in albino tissue in contrast to control plants. Exposure of barley seeds to streptomycin results in inhibition of Mg-chelatase activity in plants by 77-87% as compared to control seedlings and stimulation of Fe-chelatase on the average twice. Light and kinetin do not affect Mg-chelatase activity in white tissue of streptomycin-treated plants. There is no modification of endogenous levels of cytokinins in white tissue. Based on results obtained we propose close interaction of plastid, light and cytokinin signaling in regulation of key enzymes of Chl biosynthesis.

P-8 Functional analysis of ICE genes in wheat Mario Houde, M Badawi, YV Reddy, Z Agharbaoui, Y Tominaga, and F Sarhan Dép des sciences biologiques, Université du Québec à Montréal, CP 8888 Succ Centre-ville, Montréal, QC, Canada, H3C 3P8 houde.mario@uqam.ca Temperate cereals increase freezing tolerance (FT) by prior exposure to low, non-freezing temperatures a process called cold acclimation. It has been established that the CBF (C-repeat Binding Factors) cold response pathway is an important component of cold hardy plants. In wheat, we have identified several CBF genes that are subdivided into 10 different groups. Several CBF groups are amplified only in Pooideae and most of these groups are expressed at higher levels in freezing tolerant cultivars. These observations raise the question whether the upstream genes that regulate CBF in wheat are similar to those found in Arabidopsis. Two different Inducers of CBF expression (ICE-like genes), TaICE87 and TaICE41, were isolated from wheat and classified as ICE1- and ICE2-like genes through phylogenetic analysis. Both genes are expressed constitutively in spring and winter wheats and their encoded proteins share 94% homology within the bHLH domain. Gel mobility shift analysis showed that TaICE87 and TaICE41 can bind differentially to MYC elements in the wheat TaCBFIVd-B9 promoter. Transient expression assays in Nicotiana benthamiana, showed that both TaICE proteins can activate TaCBFIVd-B9 transcription. The complex structure of MYC elements in wheat CBF promoters and the different affinities of TaICE87 and TaICE41 for MYC elements suggest that these proteins might activate CBF differentially in wheat. Over-expression of TaICE87 and TaICE41 in Arabidopsis increased the expression of AtCBF3 and cold-regulated genes and enhanced tolerance to freezing. These results suggest that TaICE87 and TaICE41 are functional homologs of AtICE. P-9 Analysis of genetic diversity in indian mustard varieties using molecular and biochemical markers for salt tolerance Bandre A P, ≠Desai NS, and P. Suprasanna* Padmashree Dr. D.Y. Patil University, Dr. D.Y. Patil Institute for Biotechnology and Bioinformatics, CBD, Belapur, Navi Mumbai- 400 614.* Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Center, Mumbai – 400 085 neetin_desai@dypatil.edu Brassicas are an important group of edible oil crops in India, with four widely used species being B. juncea, B. napus, B. carinata and B. campestris. Mustard is a plant of the genus Brassica, (Brassica juncea L. ) amphidiploid-shrub like plant. Reported from the African and Eurosiberian Centers of Diversity, Indian Mustard (Brassica juncea L.) is reported to tolerate drought, high pH, insects, low pH, salt, smog, and weeds. The present study outlines results on the analysis of genetic diversity (“molecular profiling”) and (“biochemical analysis”) among the Indian mustard cultivars using RAPD technique, trace element analysis and effect of salt stress on membrane permeability. 15 Indian mustard varieties were analysed

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using molecular markers like RAPD markers and for 5s ribosomal DNA intergeneric non translated spacer region. RAPD analysis was carried out with 18 random decamer primers. 57 polymorphic bands were obtained out of total 89 bands. Some bands were monomorphic indicating the similarity among the varieties. Possibly this is may be due the use of same parental lines for hybridization. As per the dendrogram analysis, the cultivars were divided into four main groups based on secondary branching, which placed Pusabold, Kranti, GM-1, GM-3, RL-1359, Varuna, RH-30 into the first group; Rohini, Vardan, Urvashi, Maya into the second group and Vaibhav, Ashirwad into the third group and CS-52, CS-54 into the fourth group. The amplification of 5s rDNA NTS region was found to be completely monomorphic, suggesting that all the selected varieties were similar for the respective conserved sequence. The elemental analysis showed higher accumulation of salts like Calcium (Ca), Potassium (K) in CS-52 and CS-54 (salt tolerant varieties) indicating the elemental role in salt tolerance. These varieties also showed higher accumulation of other elements like Zinc (Zn), Strontium (Sr), Iron (Fe). Thus the RAPD markers and trace elemental analysis can be used effectively in detecting genetic diversity in Indian mustard varieties for salt tolerance. P-10 Caterpillar-specific plant defense responses Jacqueline C Bede, SA Darwish, M Chapleau, M-H Weech, L Pan, and C Ide jacqueline.bede@mcgill.ca Plants target their defense responses against the herbivore which is feeding upon it. Even different caterpillar species may elicit distinct plant defense responses. Therefore, the plant must be able to detect and distinguish between different herbivorous insects and modify their defense responses accordingly. Elicitors present in caterpillar oral secretions are released onto wounded plant tissues during insect feeding and believed to influence plant responses. By using caterpillars with intact or impaired salivary secretions, we hope to tease out the role of salivary elicitors in plant-insect interactions using the model plants Medicago truncatula and Arabidopsis thaliana. Sixteen M. truncatula genes that are differentially expressed in response to caterpillar herbivory have been identified by the differential display technique, cDNA-AFLP. Arabidopsis thaliana (L.) Heynh. genotypes limited in their ability to mount either induced resistance (IR) or systemic acquired resistance (SAR) pathways were used to elucidate the nature of cross-talk between these different defense response pathways in plant-insect interactions. Molecular and biochemical markers of IR were analyzed in plants subject to herbivory by caterpillars of the beet armyworm, Spodoptera exigua Hübner which either had intact or impaired salivary secretions. Gene expression and protein activity patterns of octadecanoid-dependent markers showed salivary-specific patterns which were disrupted in the SAR- mutant plants. These results support the model that caterpillar saliva interferes with jasmonate-dependent plant defenses by activating the SAR pathway.

P-11 A role for CML39 in programmed cell death Kyle Bender, B Vanderbeld, and W Snedden Queen’s University, Kingston, ON, Canada, K7L 3N6 7kwb@queensu.ca Many stress-responsive and developmental pathways in plant cells use Ca2+ ions as second messengers to help coordinate various signal transduction pathways. Ca2+ signals are interpreted by Ca2+ sensor proteins, such as calmodulin (CaM), which in turn regulate the activity of downstream targets including channels, metabolic enzymes, transcription factors, kinases, phosphatases, and others. In addition to the evolutionarily conserved isoform of CaM, the Arabidopsis genome is predicted to encode ~50 CaM-like genes (CMLs). While the majority of CMLs remain unstudied, research in our lab has demonstrated that a small subfamily (CML37, CML38, and CML39) is rapidly and strongly induced by various biotic and abiotic stimuli and display unique patterns of developmental expression, particularly in floral tissue. Our aim is to understand the cellular roles of these CMLs. Transgenic plants carrying single-gene knockouts (cml37, cml38, and cml39) are phenotypically normal compared to wild-type suggesting functional redundancy among CMLs. Similarly, cml37 and, cml39 do not show an altered response to various types of environmental stress. Similar experiments are underway using cml38 plants. Interestingly, transgenic plants expressing CML39 in the antisense orientation (cml39A) present a strong phenotype which includes delayed development, increased anthocyanin levels in leaves, and a severe cell-death phenotype on leaves when grown under short day conditions. Necrotic regions in cml39A leaves are associated with H2O2 production and with the deposition of phenolic compounds in the cell wall. A possible role for CML39 in calcium pathways associated with programmed cell death (PCD) will be discussed. P-12 Induction of the callus formation in Eriophorum vaginatum L Benoit and E Cholewa Dept of Biology, Nipissing University, ON, Canada, P1B 8L7 lisarose4@hotmail.com Extensive mining activities in Sudbury (Ontario, Canada) resulted in accumulation of toxic metals in soils completely destroying vegetation in surrounding area. We identified a tussock forming graminoid, Eriophorum vaginatum, as a dominant species in polluted wetlands near Sudbury. To facilitate physiological studies of metal resistance on uniform plant material, a tissue culture of E. vaginatum was initiated in this study. Induction of callus formation was performed by taking cuttings from the innermost, immature leaves in order to obtain the meristematic zones including the intercalary meristem located at the leaf base. The surface sterilized cuttings were incubated aseptically in the dark at 23ºC on Schenk and Hildebrandt (SH) medium with 30µM dicamba and 0.8% agar. The formation of a visible callus in the cuttings was observed between two to four weeks. The cuttings were transferred onto a fresh media every two weeks to maintain callus growth. Despite of the high mortality of the cuttings, some induced calluses have been maintained successfully for 18 weeks. In all induced calluses, a browning of the surface has occurred, which

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could be a possible cause of reduced rate of callus growth. The accumulation of fluorescein in the cells of the inner tissues of the callus revealed their vitality. This promising result encourages us to initiate a cell suspension culture which could facilitate formation of somatic embryos for genetic manipulation. In the future, E. vaginatum could serve as a model species to study the mechanism(s) of resistance to pollutants northern wetlands. P-13 Expression of the human rotavirus VP8::VP5∆c-term protein in plants towards the development of an edible vaccine Bergeron-Sandoval, L-P1, A Girard1, M-C St-Louis1, D Archambault1 and F Sarhan1 1Dép des sciences biologiques, Université du Québec à Montréal, CP 8888 Succ Centre-ville, Montréal, QC, Canada, H3C 3P8 bergeron-sandoval.louis-philippe@courrier.uqam.ca Human rotavirus (HRV) is the leading cause of severe gastroenteritis and is responsible for thousands of hospitalizations and deaths every year worldwide. At particular risk are children under 5 years-old in developing countries. The effectiveness of conventional vaccines, including live attenuated vaccines, could be compromised by difficulties associated with availability, storage, administration, and high production costs. Producing edible plants expressing this vaccines could circumvent some of these problems. In addition, edible vaccines are known to confer protection against pathogens that invade the intestinal mucosal surface, such as HRV. The immunogens vp8::vp5∆c-term encoding sequences were cloned into a bacterial expression vector to produce a recombinant His-tagged fusion protein. Western blot analyses using anti-His antibodies as well as VP8-specific antiserum confirmed the nature of the recombinant VP8::VP5∆c-term fusion protein. The protein VP8::VP5∆c-term was then expressed in a plant transient expression system. To ensure optimal expression of the protein, the DNA encoding-sequence was optimized for codon usage in plants and cloned under the control of the strong double constitutive CaMV35S promoter. Western blot analyses performed using the specific anti-VP8 antibody confirmed that VP8::VP5∆c-term was successfully expressed. In addition, no damage to the plant was visible, indicating that the expression of the transgene is not toxic. To our knowledge, this is the first report that shows the expression of these specific proteins in plants. Experiments are currently underway to develop stable-transformed plants and use the extract containing the proteins of interest to induce a local HRV-specific immune response in mice. P-14 The outer soybean seed coat cuticle and the origin of stone seeds K Ranathunge1,4, S Shao2,4, D Qutob3, ER Bernath1, M Gijzen3, CA Peterson1, and Mark A Bernards2 1Dept of Biology, University of Waterloo, Waterloo, ON, N2L 3G1; 2Dept of Biology, The University of Western Ontario, London, ON, N6A 5B7; 3SCPRC (London), Agriculture and Agri-Food Canada, London, ON, N5V 4T3, Canada; 4These contributed equally bernards@uwo.ca

Whether a soybean seed will be permeable or non-permeable is controlled by a thin, inconspicuous cuticle that covers the outer seed surface. An intact outer cuticle represents a nearly perfect barrier to water passage, and results in non-permeable seeds; however, the presence of minute cracks in the cuticle results in permeable seeds. We explored the chemical composition of the outermost cuticle of soybean seed coats, the timing of its deposition and the differential expression of genes during seed growth and development. We report that the soybean outer seed cuticle has an unusual chemical composition, lacking typical mid-chain-hydroxylated fatty acids but being relatively rich in other types of hydroxylated fatty acids. A disproportionately high amount of hydroxylated fatty acids was found in the outer cuticle of non-permeable seeds relative to that of permeable ones. Cuticular deposition began early in seed development, and was complete before maximum seed expansion. The resistance of the cuticle to water passage increased steadily during development until the time when cuticle synthesis had stopped but the seed was still expanding. Then cracks formed in the cuticle of permeable seeds (regardless of genotype). Once cracks formed, they become the primary site for water passage, and the cuticle lost its ability to control the process. In non-permeable seeds, no cracks appeared at this critical point and the cuticle achieved maximum resistivity at maturity. Microarray analysis of gene expression during seed coat development revealed a complex transcriptome with many genes uniquely expressed in the seed coat. Differences between permeable and non-permeable types were noted when gene expression patterns were compared at particular stages of development. These transcriptional differences provide targets for further study, to determine how they may influence the structural integrity of the outer seed coat cuticle, its resistance to cracking, and its permeability. However, the genetic control of cuticle cracking remains unknown. P-15 Soybean Root Suberin and Resistance to Phytophthora sojae K Ranathunge,1,4 RH Thomas,2,4 X Fang,1 CA Peterson,1 M Gijzen,3 and Mark A Bernards2 1Dept of Biology, University of Waterloo, Waterloo, ON, N2L 3G1; 2Dept of Biology, University of Western Ontario, London, ON, N6A 5B7; 3SCPFRC, Agriculture and Agri-Food Canada, London, ON, N5V 4T3, Canada; 4These contributed equally bernards@uwo.ca The cultivation of soybean (Glycine max L.) is hampered by the oomycete root pathogen Phytophthora sojae wherever the crop is grown. Gene-for-gene resistance to specific races of P sojae has been bred into some cultivars; however, the main method for achieving field-level control is through quantitative trait loci (QTL)-mediated (i.e., horizontal) resistance. Typically, the root is the primary site of infection by P. sojae, and we have examined suberization in soybean roots to determine whether this natural physico/chemical barrier has any bearing on defense against root pathogens. Chemical analysis of isolated soybean epidermis and endodermis tissues demonstrated increased amounts of suberin in (1) the epidermis and adjacent cortical tissue along the root axis and (2) the endodermis as roots matured. Significantly

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higher amounts of suberin (P=0.05) were found in the roots of cv ‘Conrad’, which shows a high level of field resistance to P. sojae, than in those of the susceptible line ‘OX760-6’. At the whole root level, a strong negative correlation between the amount of aliphatic suberin and field mortality was observed for nine independent cultivars (r = -0.89) as well as 32 recombinant inbred lines (r = -0.87) derived from Conrad and OX760-6. A time course of infection supports the hypothesis that it is the amount of pre-infection aliphatic suberin in the epidermal walls and middle lamellae that mediates field-level resistance of soybean to P. sojae. This idea could have broad implications for disease control as the epidermal walls of many species contain suberin. P-16 Inorganic carbon acquisition in some synurophytes algae Shabana Bhatti and B Colman York University, Dept of Biology, 4700 Keele St, North York, ON, Canada, M3J 1P3 shabana@yorku.ca Some characteristics of photosynthesis of several synurophyte algae, Mallomonas papillosa, Synura petersenii, S. uvella, and Tessellaria volvocina were investigated to determine the mechanism of inorganic carbon (Ci) uptake. All species were found to have no external carbonic anhydrase; no capacity for direct bicarbonate uptake; and a low whole-cell affinity for Ci. The internal pH of S. petersenii determined using 14C-benzoic acid and [2-14C]-5,5-dimethyloxazolidine-2,4-dione was pH 7.0 to 7.5 over an external pH range of 5.0 to 7.5. Thus, the pH difference between the cell interior of S. petersenii and the external medium was large enough, over the alga’s growth range, to allow the accumulation of Ci by the diffusive uptake of CO2. Monitoring O2 evolution and CO2 uptake by suspensions of S. petersenii at pH 7.0 by mass spectrometry did not indicate a rapid uptake of CO2 and the final CO2 compensation concentration reached was 24 ± 0.7 µM, Furthermore, when the cells were darkened a brief burst of CO2 occurred before a steady rate of dark respiration was established suggesting a loss of CO2 by photorespiration. An examination of the kinetics of ribulose-1,5-bisphosphate carboxylase/oxygenase in homogenates of cells of S. petersenii, S.uvella and Mallomonas papillosa showed that values of the Km (CO2) were 28.4, 41.8 and 18.2 µM, respectively. These species lack the characteristics of cells with a CO2-concentrating mechanism since the cell affinity for Ci appears to be determined by the relatively high CO2

affinity of the Rubisco of these algae. P-17 The microtubule plus-end binding protein EB1 and root growth responses in Arabidopsis thaliana Sherryl Bisgrove Dept of Biological Sciences, Simon Fraser University, BC, Canada sbisgrov@sfu.ca Plants are sessile and cannot relocate to a new environment when conditions become unfavourable. Instead, they control their growth to position leaves, flowers, and roots in the best possible locations. Changes in

growth often involve altering the rates and directions in which cells divide and expand. Microtubules play important roles in both of these processes. To understand how microtubules influence plant growth and development, my lab is analyzing the End Binding 1 (EB1) family of microtubule associated proteins in Arabidopsis thaliana (AtEB1). EB1 belongs to a group of microtubule associated proteins known as microtubule plus-end tracking proteins or +TIPs because they preferentially accumulate at the rapidly growing or "plus" ends of microtubules. We are analyzing A. thaliana mutants carrying large T-DNA insertions in each of the three AtEB1 genes. Mutant roots tend to grow in loops and they exhibit delayed responses to touch/gravity stimuli. Current analyses are aimed at understanding how EB1 proteins might be involved in these growth responses. Both loop formation and touch/gravity responses are regulated by the hormones auxin and ethylene and we are pursuing the possibility that EB1 function is linked to the activities of these hormones. P-18 Proteolysis over a seasonal progression in leaves of Spartina alterniflora Loisel. Mary Beth Bissell and RJ Ireland Mount Allison University, Dept of Biology, 63B York St, Sacvkille, NB, Canada, E4L 1G7 mbssll@mta.ca Spartina alterniflora is a perennial grass found in intertidal wetlands. It is native to the coasts of the Eastern Atlantic and is pivotal in the maintenance of a productive intertidal niche. Perennial plants, such as Spartina spp., exhibit different seasonal patterns of nitrogen storage and mobilization. In the fall, plants mobilize nitrogen from senescing tissues, such as leaves, to be subsequently stored in belowground structures for winter. Key photosynthetic proteins such as PsbA, PsaC and AtpB as well as RubisCO have been tracked over the season, (Morash et. al., 2005, CJB 85: 476-483) and showed RubisCO disappearance surprisingly early in the season, perhaps indicating that this abundant protein may be degraded to provide nitrogen for developing seeds. Protease activity in S. alterniflora leaves was examined over a growth season. Inhibitors for various classes of proteases were used to evaluate the relative contribution of each to the developmental process. Protease activity was determined to be at its greatest mid September, near the end of the growth season. During this time, the aspartic, trypsin-like and cysteine proteases appear to be the largest contributors to proteolysis. The contribution of the 26S Proteasome and the Clp protease system to proteolysis were also evaluated. Free ubiquitin, 3 proteasome subunits (PBA1, Rpt5, Rpn10) and the ClpP6 subunit of the Clp protease system were quantified over the season. The proteasome-related proteins and the Clp protease subunit protein all peaked, during the growth and elongation phase of the plant, and then declined gradually to the end of the season.From this study it seems that controlled proteolysis, such as that of the 26S Proteasome and the Clp protease system, contributes more to growth and maintenance of S. alterniflora, while general protease activity, most likely vacuolar protease activity, is essential during the final stages of development, senescence.

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P-19 The role of the actin cytoskeleton in the elongation and tropism of the pollen tube Firas Bou Daher and A Geitmann Institut de Recherche en Biologie Végetale, 4101 Sherbrooke est, Montréal, QC, Canada, H1X 2B2 firasbd@yahoo.com After its hydration on a receptive stigma, the pollen grain produces a cylindrical protrusion – the pollen tube – that elongates exclusively at its tip through highly localized addition of cell wall and membrane material. For the fertilization to happen the pollen tube has to grow through the stylar tissue to reach the ovule and deliver the sperm cells. During this passage, it has to produce an invasive force and to resist external mechanical compression forces against which it needs to maintain its tubular shape to allow the male germ unit to pass through. To find its way inside the style, the pollen tube has to be able to perceive and to react to external signals. At several instances it needs to drastically change its growth direction to be able to enter the micropyle and deliver the sperm cells to the egge apparatus. The pollen tube, therefore, represents an excellent model system to investigate tropic responses in individual plant cells. We are interested in the role the actin cytoskeleton plays in the elongation growth and tropic re-orientation of the pollen tube. Actin is involved in the transport of secretory vesicles and possibly affects cell morphology by direct mechanical interaction. We pharmacologically reduced or inhibited vesicle flux in order to assess how this affects pollen tube elongation and cell wall composition. The actin cytoskeleton forms a fringe-like structure close to the growth zone of the pollen tube, representing an active polymerization/depolymerization site. To elucidate the role of this cytoskeletal feature for pollen tube development and for the control of cell shape, we reduced its dynamics using actin cross-linkers. We combined this approach with an in vitro induction of tropic behavior through application of an electrical field. Our results show that the actin cytoskeleton is a key feature in determining the growth direction in this polarly growing cell. P-20 Starch granule construction: Site-detected mutagenesis of granule-bound proteins to explore structure – function relationships in puroindoline Koziol AG and I Altosaar University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON, Canada, K1H 8M5 , koziol@uottawa.ca Puroindolines (PINs) are unusual proteins, as they contain a tryptophan-rich sequence (tryptophan box) (WRWWKWWK). Tryptophan is the least common amino acid in nature, and the occurrence of up to five tryptophan residues within a stretch of eight amino acids is rare. Additionally, PINs contain ten cysteine residues, which likely participate in disulfide bond formation, providing high protein stability. Low molecular weight proteins with paired cysteines are often a hallmark of antimicrobial peptides in plants. Site-directed mutagenesis was used to modify the tryptophan residues to leucine residues (LRLLKLLK). The antimicrobial activity of the tryptophan box and the modified leucine box can be determined through their antimicrobial activities.

P-21 Hormone metabolics during the infection of corn with Ustilago maydis SA Bruce, BJ Saville, and RJN Emery Watershed Ecosystem Graduate Program, Trent University, Peterborough, ON, Canada, K9J 7B8 staceybruce@trentu.ca Ustilago maydis is a smut fungal pathogen that requires growth within a host plant to complete its life cycle. The growth of this fungal pathogen within corn plants (Zea mays) induces developmental changes such as the formation of tumors in the plant tissues. Plant growth hormones like cytokinins [CKs] and auxins [IAA] are involved in cellular differentiation and may play a role in the formation of disease symptoms of corn infected with U. maydis, especially within tumor formation. For example Agrobacterium is known to induce the overproduction of phytohormones in plant tissue that are involved in the formation of plant tumors in crown gall disease. There is also potential involvement of abscisic acid [ABA], a plant stress response hormone, which can act antagonistically to CKs. To examine whether phytohormones are involved in the U. maydis - corn infection process, profiles of 18 different CKs, as well as IAA and ABA, are being generated for infected and control plants during a time-course following infection and corresponding to symptoms at different infection stages. We also examined whether the fungus itself was capable of producing these hormones by profiling axenic cultures of the haploid and dikaryon forms of U. maydis. All of these profiles are being analyzed by liquid chromatography - tandem mass spectrometry (LC-MS/MS). Our preliminary evidence shows elevated CKs in corn shortly after infection. We also demonstrated that U. maydis is capable of producing significant quantities of CKs. The potential role of hormone changes in the plant and those caused by the fungal pathogen will be discussed. P-22 GUS reporter-aided expression analysis of a rice calmodulin gene S Phean-o-pas, Teerapong Buaboocha, and T Limpaseni Dept of Biochemistry, Faculty of Science, Chulalongkorn University, Payathai Rd, Patumwan, Bangkok 10330, Thailand Teerapong.B@Chula.ac.th Calmodulin (CaM) proteins, members of the EF-hand family of Ca2+-binding proteins represent important relays in plant calcium signals. Here, a calmodulin (OsCam1-1) gene including its promoter was isolated by PCR amplification of the genomic DNA from Oryza sativa L. cv. KDML105. The gene contains an open reading frame of 450 base pairs with a single intron at the same position found in typical plant Cam genes. By analysis using the PROSCAN program, a promoter region in which a transcription start site and a TATA box at position -26 was predicted. To investigate transcriptional activity of the OsCam1-1 gene, its promoter was fused to a β-glucuronidase gene (gus) and transgenic plants containing the construct were produced by Agrobacterium-mediated transformation. The transgenic plants exhibited GUS activity in all whole organs examined

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including leaf sheaths, leaf blades, roots and floral tissues. In cross-sections of leaves, GUS staining was observed throughout but predominantly in vascular bundles. In cross-sections of roots, GUS signal was observed predominantly in endodermis and the vascular cylinder. Strong blue staining was also observed in developing lateral roots. In addition, salt (100-300 mM NaCl) stress has been shown to increase GUS activity in leaves of the transgenic plants by nearly 2-fold within two hours of treatment. These results indicate tissue-specific expression of OsCam1-1 and its possible roles in Ca2+-mediated salt stress response. P-23 Increased air temperature during simulated autumn conditions impairs photosynthetic electron transport in Pinus banksiana F Busch, NPA Hüner, and I Ensminger (FB, NH, IE) Dept of Biology and The BIOTRON, The University of Western Ontario, London, ON, Canada, N6A 5B7; (FB) Institute of Chemistry and Dynamics of the Geosphere ICG-III: Phytosphere, Forschungszentrum Jülich, 52425 Jülich, Germany; (IE) Dept of Forest Ecology, Forest Research Institute Baden-Württemberg, 79100 Freiburg, Germany fbusch@uwo.ca The seasonal development of trees of the boreal forest might be affected by climate change, as the trees will experience naturally decreasing daylength during autumn, while warmer air temperature will maintain photosynthesis and respiration. Using a factorial design, we dissected the effects of temperature and photoperiod on the function as well as the stoichiometry of the major components of the photosynthetic electron transport chain in P. banksiana. Natural summer conditions (16-h photoperiod/22°C) and late autumn conditions (8-h photoperiod/7°C) were compared with a treatment of autumn photoperiod with increased air temperature (SD/HT: 8-h photoperiod/22°C) and a treatment with summer photoperiod and autumn temperature (16-h photoperiod/7°C). Although fully functional, the xanthophyll cycle does not appear to be a major contributor to balance the electron flow in the warm autumn treatment as it was the case in the other three treatments. Instead these plants rely on conformational changes in the light harvesting complex for safe dissipation of excess energy, resulting in a form of NPQ that is fast relaxing. Exposure to SD/HT resulted in an inhibition of the effective quantum yield associated with a decreased photosystem II/photosystem I stoichiometry coupled with decreased levels of Rubisco. Our data indicate that a greater capacity to keep P700 oxidized in plants exposed to SD/HT compared with the summer control may be attributed to a reduced rate of electron transport from the cytochrome b6f complex to photosystem I. We suggest that models that predict the effect of climate change on the productivity of boreal forests must take into account the interactive effects of photoperiod and elevated temperatures. P-24 Optimization of growth conditions for frozen stored Arabidopsis thaliana pollen Youssef Chebli, F Bou Daher et A Geitmann IRBV, 4101, rue Sherbrooke est, Montréal, QC, Canada, H1X 2B2 youssef.chebli@yahoo.ca

One of the rare weak points of the model plant Arabidopsis is the technical problem associated with the germination of its male gametophyte and the generation of the pollen tube in vitro. Arabidopsis pollen being tricellular it has a notoriously low in vitro germination rate compared to species with bicellular pollen. This drawback strongly affects the reproducibility of experiments based on this cellular system. Together with the fact that pollen collection from this species is tedious, these are obstacles for the standard use of Arabidopsis pollen for experiments that require high numbers of pollen tubes and for which the germination rates under control conditions need to be highly reproducible. The possibility of freeze storing pollen after bulk collection is a potential way to solve these problems but necessitates methods that ensure continued viability and reproducible ability to germinate. Our objective was the optimization of germination conditions for Arabidopsis pollen that had been freeze stored. We optimized the concentrations of various media components conventionally used for in vitro pollen germination. In addition to these components, medium pH and growth temperatures were tested. Here we summarize the optimized conditions for pollen germination and growth in different media and under different experimental setups. We suggest how to optimally use these methods for different practical experiments ranging from morphological observations of pollen tubes in optical and electron microscopy to their bulk use for molecular and biochemical analyses or for setups for which a specific medium stiffness is critical. P-25 Activation-tagged poplar mutant with red wood may reveal novel insights into the lignin biosynthesis pathway Claire Chesnais, J Duguay, E Harrison, S Mansfield, and S Regan Dept of Biology, Queen’s University, Kingston, ON, Canada, K7L 3N6 3cc18@queensu.ca With the completion of its genome sequence and the ongoing development of genomic tools, opportunities for the use of poplar as a model to study tree-specific traits are blossoming. One such genomic tool has been the development of an activation-tagged population of poplar trees in our lab (Harrison et al, in press). Activation tagging is an insertional mutagenesis technique which results in upregulated transcription levels of an endogenous host gene. From this population we have identified a mutant which has rose-coloured wood, named rosewood. Rose-coloured wood suggests a modification of the lignin pathway, as it has been observed in several transgenic plants downregulated for key enzymes involved in the monolignol biosynthesis pathway. If rosewood’s phenotype is due to an upregulated gene as expected, the gene responsible may represent a novel level of regulation in this pathway. Progress in confirming the upregulated gene(s) will be presented here, including determination of T-DNA copy number using Southern Blot analysis, T-DNA genomic location using a Genome Walking method, and transcription level of neighbouring genes using quantitative RT-PCR. Progress in phenotypical analysis will also be reported, including metabolic analysis of the wood and histochemical staining of the cell wall.

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Complete elucidation of the biochemistry of the lignin pathway is especially relevant in light of the role of lignin content and composition in the paper production and biofuel industries. P-26 The antioxidant and antibacterial properties of sweet fern (Comptonia peregrina) E Cholewa, B Duquette, B Dew, and P Babady-Bila Dept of Biology, Nipissing University, North Bay, ON, Canada ewac@nipissingu.ca Sweet fern (Comptonia peregrina) grows abundantly in northern Ontario. This plant’s use by Aboriginal people for number of medicinal conditions has its long history. In this study, the antioxidant capacities of several sweet fern extracts were determined using the oxygen radical absorbing capacity (ORACFL) method and the diphenylpicrylhydrazyl (DPPH) method. The sweet fern extracts analyzed consisted of a crude water extract, a butanol extract, an ethyl acetate extract, and sweet fern essential oil. The antioxidant capacity of the extracts ranged from 25.097 ± 0.104% to 53.952 ± 0.856% µM TROLOX equivalents per 0.01 g/L of extract, with crude water extract having the lowest antioxidant activity and ethyl acetate extract having the highest. The DPPH assay confirmed that ethyl acetate extract has the highest antioxidant activity, based upon calculated interpolation of standard curves where the efficient concentration (EC50) was determined to be 0.1465 g/L of extract. Standard antibacterial disk diffusion tests where performed, which demonstrated that the ethyl acetate extract negatively affects growth of Bacillus subtilis, Alcaligenes faecalis, Staphylococcus aureus and Shigella flexneri, and the butanol extract negatively affects the growth of Bacillus subtilis and Alcaligenes faecalis. The ethyl acetate, butanol, and crude water extracts had no affects on Streptococcus mutans, Pseudomonas fluorescens, Escherichia coli, Salmonella typhimurium, or Shigella sonnei. These results indicate the extracts have a fairly specific antibacterial activity that is independent of gram status. Furthermore, HPLC analysis of ethyl acetate revealed 21 peaks indicating that there are at least 21 different substances. Further fractionation of those peaks could lead to identification of specific compound with potent antioxidant properties in sweet fern. P-27 Histochemical identification of nutrients in Eriophorum vaginatum L. seeds N Roscoe and Ewa Cholewa 100 College Drive, North Bay, ON, Canada, P1B 8L7 ewac@nipissingu.ca A tussock forming sedge, Eriophorum vaginatum, dominates nutrient-poor wetlands in the northern hemisphere. Its persistence in metal polluted wetlands near Sudbury, Ontario, Canada, suggests that this species has an innate tolerance to metals. It is unknown whether the presence of E. vaginatum tussocks in metal contaminated wetlands is due to E. vaginatum vegetative propagation or reproduction from seed. In this study we describe E. vaginatum fruit and seed structure, its permeability to water and germination characteristics. E. vaginatum

flowers and develops fruits early in the growing season depending on nutrients stored in an over-wintering corm. Its fruit, an achene, is shed from the inflorescences with attached multicellular filamentous bristles which aid in wind dispersal. The seed is enclosed in a hard pericarp. The seed coat is composed of compressed epidermis with a waxy cuticle. Underlying the seed coat is one layer of aleurone parenchyma cells with thin primary cell walls. Histochemical analysis revealed that the aleurone layer is the major site of lipid storage. The endosperm is filled with starch and oil bodies, although lipids are not as abundant as in aleurone cells. In addition to starch and lipids, abundant storage proteins are located in the endosperm acting as the primary nutrient source for the developing embryo. Despite their cuticle cover and thick fruit wall, the seeds are permeable to water and are fully imbibed after 24h. We observed a low germination rate in E. vaginatum seeds collected from plants from contaminated wetlands. Our following research will focus on the effects of metals on E. vaginatum germination and seedling establishment in determining its prospective use for revegetation of environmentally compromised wetlands. P-28 Photoprotective responses of commonly grown western canadian wheat cultivars Cody J Chytyk1, PJ Hucl2, and GR Gray1, 2 1Dept of Biochemistry and 2Department of Plant Sciences, University of Saskatchewan, SK, Canada cjc160@mail.usask.ca Photosynthesis is an elaborate process by which plants convert sunlight into usable chemical energy through photochemical and biochemical reactions. Photoinhibition occurs when leaves are placed under high-light leading to a decrease in photochemical and photosynthetic efficiencies. Fifteen wheat cultivars, spanning eight market varieties, were grown under non-acclimating (20°C), cold-acclimating (5°C) and field conditions then subjected to photoinhibition. Photochemical efficiency (FV/FM) and non-photochemical quenching (NPQ) were monitored throughout on leaves from all three environments. Additionally, the induction of zeaxanthin was monitored using pigment reflectance (PRI) throughout photo-inhibition. Analyses of these parameters reveal differential photoprotective responses, specific to each cultivar, market variety and environment. It is also evident cold-acclimated and field-grown wheat were more resistant to photoinhibition than non-acclimated wheat. As a result, non-acclimated cultivars were much more dependent on zeaxanthin for photoprotection. P- 29 The establishment of two techniques to study pea nodulation Scott R Clemow and FC Guinel Dept of Biology, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, Canada, N2L 3C5 clem5940@wlu.ca Nodule formation is the result of a mutualistic relationship between the roots of certain plants and appropriate genera of bacteria. Model plants have greatly advanced our knowledge on nodulation over the last decade. This progression has pushed scientists to revisit pea as past

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nodulation studies did not account for pre-infection events in that species. The long-term objective of this research is to characterize further the role of the plant hormone cytokinin in nodulation. My short-term objectives are twofold: 1) to produce transformed composite plants, i.e. plants with transformed roots but wild type shoot, and make them nodulate; 2) to develop a successful spot-inoculation technique to visualize the first anatomical changes of the roots in response to bacterial presence. To accomplish the first objective, plants were cut through the stem and inserted into Fibrgro© cubes, inoculated with Agrobacterium rhizogenes in open Petri plates, placed in trays and covered with plastic domes. The plants were later inoculated with Rhizobium leguminosarum. Because the A. rhizogenes used in this study carries a GUS reporter gene, a GUS assay was performed to determine which roots were transformed and the nodules on those roots were counted. To achieve the second goal, plants were pre-germinated on Petri plates for 48 hours, transferred to germination pouches containing water and inoculated with R. leguminosarum carrying a lacZ reporter. These plants were harvested 5 days after inoculation, exposed to lacZ staining solution and embedded in agar for sectioning. The sections were visualized under a light microscope for signs of infection. Composite plants with nodulated transformed roots were obtained and the transformation efficiency is comparable to that of other legumes reported in the literature. Spot-inoculation was successful with early infection events caught at the site of infection. These two techniques will be useful in our lab as a transformed pea system would allow the alteration of cytokinin levels via insertion of specific genes while spot-inoculation would allow the visualization of the effects these changes would have on nodulation. These techniques will be applied in the future to the study of the collection of mutants own by our lab. P-30 Photosynthetic inorganic carbon acquisition in an acid-tolerant, free-living species of Coccomyxa (Chlorophyta) V Verma1, S Bhatti1, VAR Huss2, and Brian Colman1 1Dept of Biology, York University, Toronto, ON, Canada; 2Dept für Biologie, Molekulare Pflanzenphysiologie, Friedrich-Alexander-Universität,ErlangenNürnberg,Germany colman@yorku.ca The processes of CO2 acquisition were characterized for the acid-tolerant, free-living chlorophyte alga, CPCC 508. rDNA data indicate an affiliation to the genus Coccomyxa, but distinct from other known members of the genus. The alga grows over a wide pH range of pH 3.0 to 9.0. External carbonic anhydrase (CA) was detected in cells grown above pH 5, with the activity increasing marginally from pH 7 to 9. The capacity for HCO3- uptake of cells treated with the impermeable CA inhibitor acetazolamide (AZA), was investigated by comparing the calculated rate of uncatalyzed CO2 formation with the rate of photosynthesis. Active bicarbonate transport was found in cells grown in media above pH 7.0. Monitoring CO2 uptake and O2 evolution by membrane-inlet mass spectrometry demonstrated that air-grown, AZA-treated cells caused a rapid drop in extra-cellular CO2 concentration to a CO2 compensation concentration of 27.03 µM at pH 8.0; this CO2 concentration is above the equilibrium concentration at this pH, indicating that the cells do not exhibit active

uptake of CO2. O2 evolution continued when cells reached CO2 compensation point, confirming the capacity of these cells for active bicarbonate uptake. The CO2 fixation kinetics of cell-free homogenates of the alga showed that it possesses a Rubisco with a Km (CO2) of 37±0.56. These results indicate that this free living Coccomyxa lacks a CO2 concentrating mechanism but possesses an active bicarbonate uptake system unlike the Coccomyxa found in symbiotic association with lichens. P-31 AtMEK1 knockout mutant and its responses to various stresses in Arabidopsis Chad Conroy, M Hemmati, H Hemmati, and T Xing Dept of Biology, Carleton University, Ottawa, ON, Canada, K1S 5B6 tim_xing@carleton.ca tMEK2, a tomato mitogen-activated protein kinase kinase (MAPKK or MEK), has been used as a part of a model system in our study of MAPK pathways. Expression in tomato, Arabidopsis and wheat has been shown to enhance the resistance to various plant pathogens. The high homology between tomato tMEK2 and Arabidopsis AtMEK1 allows for the testing of complementation between tMEK2 and AtMEK1. Arabidopsis AtMEK1 T-DNA knockout mutants have been studied. Phenotypes have been observed, ranging from root formation, hormone response, to plant size. In various abiotic stresses, these mutants significantly altered their responsiveness to high salinity. Protein profile analysis has identified potential downstream targets of AtMEK1. The findings may help in developing strategies for stress tolerance and disease resistance. P-32 The role of the mitochondrion and alternative oxidase during Pseudomonas syringae infection of Nicotiana tabacum leaves Marina Cvetkovska, S Amirsadeghi, and GC Vanlerberghe Dept of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada, M1C1A4 mcvet@utsc.utoronto.ca Beside their key role in metabolism and cellular bioenergetics, plant mitochondria may have additional roles in cellular signaling, such as has been found in other organisms. For example, the mitochondrial electron transport chain (ETC) is a source of reactive oxygen species (ROS) and these ROS have been hypothesized to have signaling functions within the cell. In this respect, it is of interest that plant mitochondria have an alternative oxidase (AOX), the function of which could act to modulate ROS signaling. We are investigating the potential role of the mitochondrion during infection of Nicotiana tabacum leaves with the pathogenic bacterium Pseudomonas syringae. Three different strains of P. syringae are being used, each of which induce specific cellular responses. The virulent strain P. syringae pv. tabaci rapidly proliferates in the leaf, causing disease that quickly culminates in a necrotic-like leaf cell death. P. syringae pv. phaseolicola is a non-host strain that does not proliferate or cause disease, but which does induce some defense

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responses. Finally, P. syringae pv. maculicola is a non-host strain that proliferates moderately and which induces defense responses that include the appearance of hypersensitive response-like lesions, a type of programmed cell death (PCD) in plants. We find that infection with pv. phaseolicola induces a rapid and early increase in AOX gene expression not seen after infection with pv. maculicola or pv. tabaci. In the case of pv. tabaci, there is an increase in AOX expression but only very late, when necrotic death is already underway. We hypothesize that these differences in AOX expression reflect differences in accumulation of salicylic acid (SA), a key signaling molecule during plant-pathogen interactions. To investigate this, we will measure changes in SA concentration after infection with the different P. syringae strains. SA is well-known to effect AOX gene expression and this is perhaps due to direct effects of SA on mitochondrial function. We have also treated Nicotiana tabacum suspension cells with concentrations of SA that induce either defense responses without PCD, a defense response that includes PCD or a necrotic-like cell death response. Similar to the results with P. syringae and leaves, we find that AOX gene expression is induced very early during a defense response that does not include PCD but not in cells that will undergo PCD. To date, our results suggest that suppression of AOX gene expression may be a requisite event promoting PCD. This will be further investigated using transgenic plants with altered AOX gene expression. P-33 Photosynthetic Response of Winter and Spring Cereals to Short-Term Elevated CO2 K Dahal1, N Huner1, and B Grodzinski2 1The University of Western Ontario, Dept of Biology, North Campus Bldg, London, ON, Canada, N6A 5B7; 2The University of Guelph, Dept of Plant Agriculture, Bovey Bldb, Guelph, ON, Canada, N1G 2W1 kdahal@uwo.ca Photosynthesis is the principal physiological mechanism through which terrestrial plants sense and respond directly to, rising atmospheric CO2 concentrations and changing temperatures. Cold acclimated winter cereals grown at ambient CO2 exhibit an increased capacity for light saturated rate of photosynthesis compared to cold acclimated spring cereals. This increased light saturated rate of photosynthesis in cold acclimated winter cereals results from increased sink demand, enhanced carbon export to sink and up-regulated photosynthetic gene expression. Since winter cereals grown at ambient CO2 exhibit a differential increase in photosynthetic capacity upon cold acclimation compared to spring cereals, exposure to elevated CO2 (700 ppm) should enhance the differential increase in photosynthetic capacity in cold acclimated winter cereals compared to spring cereals. The overall objective of this research is to assess the effect of short term elevated CO2 on the light saturated rate of photosynthesis and to evaluate the temperature dependence of the stimulation of CO2 assimilation in non acclimated and cold acclimated winter and spring wheat and rye cultivars. We observed growth of 1/3 for plants grown at 5 OC compared to plants grown at 20 OC for all cultivars; however dry weight to fresh weight ratio and specific leaf weight increased by 2 to 3-fold in cold acclimated versus non acclimated winter genotypes. Cold

acclimation enhanced photosynthetic capacities by 20-25% in winter cereals however photosynthetic capacities decreased by about 30% in spring cereals. Elevated CO2 stimulated the light saturated rate of photosynthetic capacities in all cultivars at 20 OC. The stimulation was observed with the first 6 hours and reached a maximum (50-60%) after 36 hours of exposure to elevated CO2 and

tended to decline subsequently. Cold acclimation further enhanced CO2 stimulated photosynthetic capacity in winter cereals and reached to about 90% at elevated CO2 compared to cold acclimated plants exposed to ambient CO2. In contrast, cold acclimation inhibited CO2 stimulated photosynthesis in spring cereals. Short-term exposure to elevated temperature (40OC, 35OC, 30OC) significantly inhibited the CO2 stimulated photosynthetic capacities irrespective of cultivars and cold temperatures. We can conclude that CO2 stimulated photosynthesis is temperature sensitive. We will further study the effect of short term elevated CO2 on chlorophyll fluorescence, photosynthetic genes expression and enzyme abundance in cold acclimated and non acclimated winter and spring cereals. P-34 Activity and transcript changes of nitrate reductase (NR) and glutamine synthetase (GS) in Arabidopsis seedlings exposed to NaCl stress Mohamed Debouba1, H Gouia1, MH Ghorbel1, and A Suzuki2 1Institut Supérieur de Biologie Appliquée de Médenine, Route El Jorf 4119, Médenine, Tunisie ; 2Unité de Nutrition Azotée des Plantes, INRA, Route de Saint-Cyr, 78026 Versailles cedex, France Mohamed.debouba@fst.rnu.tn Arabidopsis thaliana (ecotype Columbia) seedlings were grown on either NO3- (NO3--plants) or NH4+ (NH4+-plants) during one month. Plants were then divided into control and 100 mM NaCl stressed during two weeks. At harvest, fresh weigh (FW) accumulation decreased by about 75% relative to control in both leaves and roots of salt treated NO3--plants; while NaCl stress effects on growth were less pronounced (20%) when plants were fed with NH4+. Nitrate reductase activity (NRA) and NR transcripts (NR1, NR2) were not significantly affected by salt stress in the leaves and roots of NH4+-plants. In NO3--plants, inhibition by salt of NRA in the leaves was associated with a decline in NR2 levels, and conversely salinity increased NRA and NR2 in roots. These findings are in favour of a predominant role of NR2 relative to NR1 in the determination of NRA under salt stress. In both NO3- and NH4+ medium, NH4+ assimilation by glutamine synthetase (GS) was inhibited by NaCl after one week in the leaves, and this was associated with a comparable decline in GS2 transcript levels. While, no significant effects of NaCl could be observed in GS1 isoforms (gs1-1, gs1-2 and gs1-3) in NO3- and NH4+-plants. GS activity was enhanced by salt stress during first and second week in the roots of NO3--plants and NH4+-plants, respectively. The salt-induced stimulation of GS activity in the roots of NO3--plants was concomitant with an overall increase of GS2 and GS1 transcripts. Results obtained in the present work informed that growth salt sensitivity, in glycophyte plants such as Arabidopsis, displayed transcriptional changes that partially regulated nitrogen metabolism enzymes. Growth in NH4+-plants was slower

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than in NO3--plants, but transcripts of NR and GS were more stable under salt stress when NH4+ was the nitrogen source. This may explain why a small fraction of NH4+ should be usually supplied with NO3- in plant soil. P-35 Identification of calmodulin protein targets in soybean nodules by phage screening TA DeFalco and WA Snedden Dept of Biology, Queen’s University, Kingston ON, Canada, K7L 3N6 3tad1@queensu.ca The use of calcium ions (Ca2+) as a secondary messenger plays a key role in many eukaryotic cell signaling pathways, often through the action of the ubiquitously expressed Ca2+-binding protein calmodulin (CaM). CaM is an evolutionarily conserved eukaryotic protein that functions as a Ca2+ sensor and regulates the activities of dozens of other cellular proteins. Recent work has shown that Ca2+/CaM signaling is critical for proper initiation and formation of nodules in soybean (Glycine max) during symbiotic interactions with Rhizobium. In order to understand the role of Ca2+/CaM during nodule/legume symbiosis it is necessary to identify and study the downstream targets of CaM. To date, the most successful protein-protein interaction strategy for the isolation of CaM targets in plants has been to screen lamda phage cDNA expression with 35S-methionine radiolabeled recombinant CaM. We constructed and screened a soybean nodule library and, as a testament to the validity of the method, were able to isolate a number of previously identified CaM targets including cyclic-GMP gated ion channels, kinesin-like proteins, and CBP-60s. In addition, we have also identified several novel putative CaM targets which include proteins of both known and unknown function. Investigation into these novel CaM-binding proteins is currently underway and their possible roles in nodule signaling will be discussed. P-36 Identification of vascular patterning regulatory elements in Arabidopsis thaliana. TJ Donner and E Scarpella Dept of Biological Sciences, University of Alberta, Edmonton, AB, Canada, T6G 2E9 tdonner@ualberta.ca, enrico.scarpella@ualberta.ca Vascular tissues play an essential role in plant development. Not only are these tissues required for the transport of nutrients, but they also regulate both the external architecture and internal structure of plants1. In leaves, files of elongated vascular cells differentiate from isodiametric precursors2,3, which can only be distinguished from the surrounding non-vascular cells because they express the Arabidopsis thaliana homeobox 8 gene (Athb8)4,5. To understand the signaling mechanism by which these vascular precursors are selected, we have visualized fluorescent reporter gene expression profiles conferred by progressive 5′ and 3’ deletions of the Athb8 promoter. We have identified a 37-bp upstream regulatory region required for expression in vascular precursors. Interestingly, no canonical consensus sequence for known transcription factor binding sites is present in this 37-bp region, suggesting that the regulatory sequence necessary

for vascular precursor gene expression represents a novel control element. We are currently narrowing down the regulatory region required for vascular precursor gene expression to identify a single transcription factor binding site. In future work, we will test sufficiency of the identified element for gene expression in vascular precursors. Our work will identify the first regulatory element to specifically confer vascular precursor gene expression and, by identifying the transcription factors binding to this ‘vascular precursor element’, allow us to begin to elucidate the mechanism by which vascular precursor cells are selected. 1Berleth and Sachs (2001) Curr Opin Pl Biol 4:57-62. 2Foster (1952) Am J Bot 39: 752-66. 3Esau (1965) Plant Anatomy, NY, John Wiley. 4 Kang and Dengler (2004) Int J Plant Sci 165:231-42. 5 Scarpella et al. (2004) Dev 131: 3445-55. P-37 Transgenic potato roots transformed to underexpress cytosolic triosephosphate isomerase show alterations in central carbon metabolism Dorion S1, Clendenning A1, Parveen N1, Jeukens J1, Haner A2, Law RD2, and Rivoal J1 1IRBV, Université de Montréal, 4101, rue Sherbrooke est, Montréal, QC, H1X 2B2; 2Dept of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E, Canada dorionsonia@hotmail.com Triosephosphate isomerase (TPI) catalyzes the interconversion of dihydroxyacetone–P and glyceralde-hyde 3-P in the glycolytic pathway. Cytosolic TPI catalyzes an equilibrium reaction and is generally considered as a housekeeping enzyme. Using potato as a model system, we have previously shown that cytosolic TPI constitutes the bulk of extractable TPI activity in all tissues and that its expression is developmentally regulated. Here, we present the results of a transgenic approach to examine the metabolic function of cytosolic TPI in non-photosynthetic tissues. An antisense construct for cytosolic TPI was introduced in potato using the binary vector pGA643 and Agrobacterium rhizogenes. The resulting population of transgenic root clones displayed 30-100% of the TPI activity found in control clones carrying an empty binary vector. Western blot analysis and analytical chromatography on DEAE Fractogel demonstrate that the antisense strategy only affects the cytosolic TPI isoform, while levels of plastidic TPI activity remains unchanged. Transgenic roots were characterized with respect to the activity of glycolytic enzymes, their metabolite contents, oxygen uptake and various carbon fluxes. Metabolite profiling of sugars, organic acids and amino acids as well as 14C-glucose flux analyses indicate that an important reduction of cytosolic TPI activity affects several aspects of root carbon metabolism. Antisense roots containing the lowest amounts of cytosolic TPI show an increased flux of C through the pentose phosphate pathway. Consistent with these findings, these clones have increased levels of aromatic amino acids and an increased capacity for lipid synthesis. These results reveal that plastidic TPI does not take over the carbon flux if the reaction of its cytosolic counterpart is inhibited and that cytosolic TPI plays a role in the balance of carbon fluxes in plant root primary metabolism. (Supported by NSERC)

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P-38 Activation tagging in potato: a useful tool for functional genomics Duguay JL1, Gustafson2 V, and S Regan1 1 Biology Dept, Queen’s University, Kingston, ON, K7L 3N6; 2

BioAtlantech, 921 College Hill Rd, Fredericton, NB, E3B 6Z9, Canada 5jld3@queensu.ca This study has been undertaken to examine the utility of activation tagging in the tetraploid genome of Solanum tuberosum, the world’s fourth most important food crop. Activation tagging generates dominant, gain-of-function mutations through Agrobacterium-mediated integration of four enhancers from the CaMV 35S promoter into the host’s genome, resulting in the up-regulation of a proximal gene. Recently, the Canadian Potato Genome Project (CPGP) generated more than 8500 activation-tagged potato lines, comprising the world’s largest mutant potato collection. In a preliminary greenhouse screen of 677 lines, several prominent mutants were identified with morphological anomalies in the leaves, stems, flowers or tubers. Overall, the phenotypic mutant frequency for this screen was approximately 3%. One interesting mutant identified, named Twiggy Lafleur, produced more flowers, flowered earlier and longer than wild-type and exhibited increased stem branching compared to controls. A modified TAIL-based PCR strategy revealed the T-DNA inserted near a MADS-box transcription factor, that when over-expressed in tobacco and potato, shows a phenotype similar to that observed in the activation-tagged line. A second mutant, named Chocolate, shows no discernible change in the above-ground tissues, but displays a striking tuber phenotype characterized by a thick, dark-brown coloured skin. The physiological basis for the altered skin colour is unknown, but attempts are being made to determine the T-DNA insertion point for this mutant. To get an indication of the molecular complexity of the population, southern blotting was performed on 10 lines. Probes specific for several T-DNA regions confirmed the presence of the transgene in all of the tagged lines analysed, with an average copy number of 1.5. Finally, a targeted disease resistance screen is underway to assess the population for altered responses to Phytophthora infestans, the causal agent of late blight. With over 600 lines examined to date, several candidates have shown differential responses to infection and have been selected for further analysis. Taken together, these results show that the activation-tagged population is a valuable resource for gene discovery in the complex potato genome and holds vast potential for the functional characterization of genes that underlie important potato traits. P-39 A tissue culture system facilitates examination of gene expression during vegetative dormancy emergence in the potato tuber shoot apical meristem Christopher A Edmunds, LC Sinnemaki, and RD Law Dept of Biology, Lakehead University, 955 Oliver Rd, Thunder Bay, ON, Canada, P7B 5E1 dlaw@lakeheadu.ca The control of gene expression in the shoot apical meristem (SAM) of plants is of considerable recent

research interest, as the totipotent cells it contains eventually form all of the aerial parts of the plant. Life-cycle transitions dependent on SAM reprogramming, such as florigenesis, have been and continue to be well studied, while the molecular factors governing others, such as endodormancy, remain largely unidentified. The lack of an effective control that retards meristem growth in potato tubers results in the spoilage of a considerable portion of this crop in storage. We have used potato microtuber cultures to examine SAM gene expression during emergence from vegetative dormancy. This culture system possesses several advantages over field-grown tubers, including reproducibility and the ability to harvest and analyze large numbers of physiologically and biochemically identical meristems at any time of year. We have used quantitative real time polymerase chain reaction to measure the relative expression levels for several housekeeping/reference and endodormancy related genes during meristem regrowth. Our goal is to identify genes whose expression changes during early emergence regulate this process and thus increase understanding of the metabolic controls that regulate vegetative growth in this important crop plant. P-40 Meristem regulation during Brassica napus microspore-derived embryogenesis Mohamed Elhiti and C Stasolla Dept of Plant Science, University of Manitoba, 222 Agriculture Bldg, 66 Dafoe Rd, Winnipeg, MN, R3T 2N2 umelhiti@cc.umanitoba.ca

Over the past few decades, canola microspore derived embryos (MDEs) have been widely used to study embryo development in culture. However, embryo aberrations, resulting in reduced conversion frequency and plant regeneration, are often observed in vitro. These aberrations include (1) the appearance of intercellular spaces among the stem cells of the shoot apical meristem, (2) the differentiation of the meristematic cells, and (3) a change in storage product deposition pattern. This study intends to determine the relation between the structure of the shoot apical meristem and expression of both BnSHOOTMERISTIMLESS (BnSTM) and BnCLAVATA1 (BnCLV1), two meristem marker genes isolated from canola tissue. We have used several different treatments in our attempt to alter the architecture of the shoot apical meristems. In the first treatment, GSSG and buthionine sulfoximine (BSO), an inhibitor of reduced glutathione (GSH), were applied to the culture medium to enhance SAM formation and functionality (Belemonte et al, 2006). In other treatments we used triidiobenzoic acid (TIBA), an inhibitor of auxin transporter PIN1 protein, indole acetic acid (IAA), and reduced glutathione (GSH) to the medium. These compounds induce meristem deterioration and result in poor plant regeneration. Our results showed that BnSTM expression is induced by applications of BSO and GSSG in all developmental stages of embryogenesis. Application of IAA, TIBA, and GSH, however, suppressed the expression of BnSTM. These results indicate that the expression of BnSTM is directly associated by the SAM structure. The expression of BnCLV1 was not affected by BSO applications, although the expression of this gene was strongly suppressed by GSH. The expression of BnCLV1 was repressed by TIBA and IAA, especially during the later

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stages of embryo development. These results suggest that the expression pattern of BnCLV1 is also related to the quality of the apical meristems during the late embryonic phases. RNA in situ hybridization is currently being used to study the localization patterns of both gene transcripts following the treatments described above.

P-41 Defining the Functionanl Significance of Adenosine Nuclesidase Katja Engel1, Hanna Blaschke2, Klaus V. Schwartzenberg2, Barbara Moffatt1 1Dept of Biology, University of Waterloo, 200 University Ave West, Waterloo, ON, Canada, N2L 3G1; 2 Biocentre Klein Flottenbek, University of Hamburg, Ohnhorstr. 18, D-22609 Hamburg, Germany kengel@uwaterloo.ca Adenosine nucleosidase (ADN) catalyzes the conversion of purine ribosides to their corresponding bases. Although the activity of this enzyme has been described in several plant species, no corresponding genes have been identified to date, nor have its contributions to plant development been elucidated. Several studies suggest a possible role in cytokinin metabolism as well as adenosine recycling. Recently it has been demonstrated that the genome of the moss Physcomitrella patens contains 3 sequences with 26% amino acid identity to an inosine-uridine nucleoside hydrolase sequence from Crithidia fasciculata. This gene was found to have nucleotide similarity to two A. thaliana genes: At1g05620 (ADN1) and At2g36310 (ADN2), which are currently annotated as inosine-uridine preferring nucleoside hydrolase family proteins. We have initiated a functional analysis of these two genes by examining the corresponding recombinant enzyme activities and T-DNA insertion mutants. The ADN1 and ADN2 cDNAs were cloned into pET28a to allow for the production of N-terminal His-tagged proteins in E. coli. The recombinant proteins were purified using affinity chromatography and their activity was monitored using a spectrophotometric assay. Preliminary results show ADN2 accepts both inosine and adenosine as substrates whereas ADN1 did not show enzymatic activity under the tested conditions. T-DNA knockout lines for each ADN gene were analyzed and found to be morphologically normal; double mutants had a distinct phenotype including smaller rosettes, delayed shoot development and reduced fertility. Further research will investigate the substrate specificity of these putative ADN genes, and their possible function in adenosine recycling and cytokinin homeostasis. P-42 The use of fluorescence spectroscopy to study protein-protein interactions between receptors involved in protein import into chloroplasts Wesley A Farquharson, AG Szabo, and MD Smith Depts of Biology (WAF and MDS) and Chemistry (AGS), Wilfrid Laurier University, Waterloo, ON,Canada, N2L 3C5 farq9130@wlu.ca The Translocon at the Outer envelope membrane of Chloroplasts (TOC complex) is responsible for the import of approximately 95% of the proteins required for chloroplast biogenesis and function. Within this TOC complex are found two families of GTPases critical for the import of nuclear-encoded proteins. TOC159 (atTOC159/132/120)

and TOC34 (atTOC34/33) gene families in Arabidopsis thaliana encode the primary receptor and facilitation machinery required for specific and efficient import of chloroplast-destined proteins. It has been hypothesized that functionally and structurally distinct TOC complexes form via specific interactions between these two families of proteins. In particular, atTOC159 with atTOC33 and atTOC132/120 with atTOC34, seem to be responsible for the import of photosynthetic and non-photosynthetic proteins, respectively. The current project investigates the hypothesis that the interaction between specific members of the TOC159 and TOC34 families is mediated by their GTPase domains. The putative binding domain(s) and the molecular properties that confer specificity to the interaction(s) between family members will be determined using biophysical techniques, such as fluorescence spectroscopy. Fluorescence spectroscopy is a powerful tool for testing protein-protein interactions. By manipulating the location of fluorescent amino acids the interactions between specific members of the TOC159 and TOC34 families can be characterized on the basis of fluorescence quenching and activation. The rationale, preliminary data, and future experimental directions will be presented. P-43 A novel phytochemical study of canadian populations of Rhodiola rosea L. Vicky J Filion1, M Archambault2, A Saleem1, G Rochefort3, M Allard3, A Cuerrier2, and JT Arnason1

1CAREG, Dept of Biology, University of Ottawa, Ottawa, ON, K1N 6N5; 2Plant Biology Research Institute, Université de Montréal, Montréal, QC, H1X 2B2; 3Nunavik Bioscience Inc, Montréal, QC, H4M 2X6, Canada vjfilion@gmail.com, John.Arnason@uottawa.ca Rhodiola rosea L. or "roseroot" (Crassulaceae) is an economically important medicinal plant from Eurasia, which has both traditional and commercial usage. The therapeutic properties of roseroot include immuno-stimulant, anti-depressant and adaptogenic influences. This study examined for the first time various populations of R. rosea growing along the eastern Canadian coasts. Phytochemical analysis using reverse phase high performance liquid chromatography showed the presence of five pharmacologically active compounds (salidroside, tyrosol, rosavin, rosarin and rosin) in the Canadian plants. Several collection samples, obtained from different origins such as Canada, Norway and Siberia, were compared to determine phytochemical variation according to the region of collection. Although, the Eurasian medicinal plant material contained higher concentrations of bioactive phytochemicals, Canadian R. rosea plants showed potential as medicinal crop. P-44 The effects of different fertilizer prescriptions on wheat yield and quality under immature soil conditions Zhi-Qiang Gao1, 2, Bao-Luo Ma2, Ping-Ping Zhang1, Min Sun1, Guo-Yuan Miao1 1Agronomy college, Shanxi Agricultral University, Taigu 030801, Shanxi, P.R. China 2ECORC, Agriculture & Agri-Food Canada, 960 Carling Ave, Ottawa, Ontario, Canada K1A 0C6 mab@agr.gc.ca

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Fertilization strategy is not only the main means of raising grain yields, but also the important measures to improve grain quality in cereal crop production. While different views are reported about the effects of fertilizer treatments on wheat quality, most results often came from high level production and good soil conditions. In this study, immature soils from the C horizon of soil profile were used to assess the effects of nitrogen (N), phosphorus (P), potassium (K) and organic fertilizer on wheat yield and quality with minimal impact of uncontrollable soil macro- and micronutrients. A greenhouse experiment with winter wheat cv. Zhongyou 9507, a high protein genotype was conducted with the following nine treatments: 207 kg N ha-

1 as urea, 135 kg P ha-1 as superphosphate, 78 kg K ha-1 as potash sulfate, poultry manure (75000kg/ha), N+P, N+K, N+P+K, N+P+K+manure, and CK. The results showed that among N, P and K treatments, P was the most important yield determining factor in the calcareous barren soil of loess in northern China, and without P addition, N, K, and N+K treatments almost couldn’t produce meaningful yield even if there were sufficient supplies of N and K in the calcareous soil regions. Organic fertilizer played very important roles in soil nutrient supply, formation of yield and grain quality due to its whole nutrients and long-lasting of nutrient supply. P-45 Quantification of intracellular vesicle trafficking using spatio-temporal image correlation spectro-scopy (STICS) - Plant cell morphogenesis requires highly targeted delivery of building material to spatially confined sites on the cell surface Anja Geitmann1, J Bove1, and B Vaillancourt2 1IRBV, Dép de sciences biologiques, Université de Montréal, 4101,rue Sherbrooke est, Montréal, QC H1X 2B2; 2Dept of Physics, McGill University, 3600, rue Université, Montréal, QC, H3A 2T8, Canada anja.geitmann@umontreal.ca Plant cell growth and morphogenesis are accompanied by dramatic changes in cell shape. These require the concerted action of two mechanical processes involving the cell wall: the deformation (stretching) of the existing cell wall and the localized secretion and deposition of new cell wall precursors. The latter process adds cell wall material to prevent the thinning of the stretched wall resulting from the former. Furthermore, exocytosis has the capacity to influence local mechanical properties of the cell wall by adding softer cell wall material or by inserting softeners such as expansins. The precise targeting of the secreted material is, therefore, pivotal in order to obtain a particular change in cell shape. Cell wall material for growing plant cell surfaces is delivered in secretory vesicles. Due to their small size (below the resolution of the optical microscope), the quantification of the dynamic trafficking of these vesicles represents a challenge. We used spatio-temporal image correlation spectroscopy (STICS) in combination with high temporal resolution confocal imaging to quantify vesicle trafficking in the rapidly growing pollen tube. In tip growing cells such as pollen tubes and root hairs, the surface expansion and secretion events are limited to an extremely small area at the very tip of the cell. This spatial confinement results in a unidirectional growth pattern characterized by a single target zone for vesicle delivery. Our goal was to monitor

the intense vesicle trafficking in the vicinity of the growth zone at the tube apex. To this end we labeled the vesicles with phosphomembrane fluorescent dyes and quantified the spatial and temporal aspects of their movement patterns. These revealed that the average vesicle repeatedly passes the secretion zone to eventually obtain the opportunity to release its contents. Furthermore, a large fraction of vesicles must deliver cell wall material by some sort of kiss-and-run exocytosis since the growing plasma membrane surface requires considerably lower numbers of complete vesicle fusions than the expanding cell wall. The vesicle trafficking in the pollen tube apex therefore is a precisely controlled and highly efficient transport system that is responsible for the pollen tube's astonishing ability to grow tens of micrometers per minute. P-46 The role of the microtubule associated protein End Binding 1 (EB1) in root growth responses Laura Gleeson, C Chen, and S Bisgrove 1110 Chateau Pl, Port Moody, BC, V3H 1N6, Canada ljg5@sfu.ca Roots are able to navigate around obstacles in the soil, grow towards moisture and respond to gravity. Roots change the direction of their growth by bending. Bends are formed by a process called differential growth, when the cells on the upper flank of the root elongate faster than the cells on the lower flank. Microtubules are important for cell elongation and we are investigating how they influence growth responses in plants. Microtubules are dynamic structures under tight regulation by a myriad of microtubule associated proteins. We are studying one group of microtubule associated proteins, the End Binding 1 (EB1) family. EB1 is a +TIP that localizes to the more rapidly growing or plus ends of microtubules. In Arabidopsis, there are three members of the EB1 family and we have isolated mutants carrying T-DNA insertions in each of the three EB1 genes. On inclined agar plates, eb1 roots tend to form more loops than wild type plants and they exhibit delays in bend formation in response to gravity/ touch stimuli. In addition, mutant roots skew more to the left than wild type plants, a phenotype that might also be associated with delayed responses to gravity. Based on these phenotypes, we hypothesize that EB1 has a role in bend formation and I am interested in understanding how EB1 might be involved. Studies on EB1 in animal and fungal cells suggest that the proteins have two functions. 1) When bound to a microtubule EB1 influences how rapidly the microtubule grows and shrinks. 2) EB1 also associates with non-tubulin proteins and it plays a role in the interactions of microtubule ends with other proteins or structures in the cell. Microtubule binding has been mapped to the calponin homology (CH) domain positioned closer to the amino terminus of the protein while the ability to interact with other proteins appears to be mediated by amino acids in the EB1 domain, located towards the carboxyl terminus. To understand how EB1 might be involved in root bending, I am making full-length and truncated EB1 constructs with and without GFP. The truncated constructs contain either the CH or the EB1 domain and expression is driven by either the native EB1 or the cauliflower mosaic virus promoter. I am transforming constructs into mutant plants and I plan on assaying the ability of each construct to bind microtubules and to restore root growth responses to those of wild type plants.

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P-47 Increase in specific proteins associated with the desiccation of tolerant roots of a horticultural dicot, Ranunculus asiaticus Yujie Gong and JD Bewley Dept of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1 ygong @uoguelph.ca Ranunculus asiaticus is a horticultural dicot that is able to tolerate long-term desiccation during its annual life cycle. The annual cycle of desiccation and resurrection of R. asiaticus is correlated with the presence of a putative storage protein (JR14) and stress-related proteins (dehydrins and smHSPs) in its underground storage organs, the tuberous roots. A 489bp full length JR14 cDNA sequence and a 615bp genomic sequence were obtained by 3’-RACE and 5’-RACE PCR using oligonucleotide sequences based on the terminal amino acid of the mature protein. A 545bp probe based on the JR14 genomic sequence detected at least 4 homologs by Southern blot. SDS-PAGE analysis of total proteins extracted from different organs of R. asiaticus revealed that JR14 is specifically expressed and synthesized in tuberous roots but not in above-ground vegetative organs such as leaves and stems. Western blots indicated that the expression of dehydrin Dhn20 (LEAII D-11 family) is induced by dehydration and ABA but not by salt, and declines upon rehydration. However, the expression of Dhn20 could be only induced by ABA within 8h. As with dehydrins, smHSPs were also detected by western blots in the tuberous roots during desiccation, and their expression was induced by high temperature, dehydration and salt, but not obviously induced by ABA. The gel filtration chromatograph showed that smHSPs may act as molecular chaperons which are able to bind to other molecules during desiccation to protect them from damage. The possible interaction between the JR14 protein and smHSPs has been determined using the S-tagged JR14 protein and total proteins extracted from desiccated roots. P-48 In vivo phosphorylation of the PEP carboxylase AtPPC1 in phosphate-starved Arabidopsis thaliana Allison Gregory, VL Knowles, BA Hurley, and WC Plaxton Dept of Biology, Queen’s University, Kingston, ON, Canada, K7L 3N6 4ag9@queensu.ca Soil phosphate (Pi) scavenging by Pi-starved (-Pi) plants is thought to arise from the induction and phosphorylation-activation of PEP carboxylase (PEPC), resulting in root excretion of large amounts of organic acids. This acidifies the rhizosphere, facilitating root Pi uptake by solubilizing rock-Pi. Although PEPC protein kinase transcripts show a striking accumulation in –Pi Arabidopsis, no Arabidopsis PEPC has been biochemically characterized nor shown to be phosphorylated during Pi stress. PEPC specific activity increased by ≥200% 7-d following transfer of Arabidopsis suspension cells or seedlings to -Pi growth media. This was paralleled by a similar increase in the amount of an immunoreactive 107-kDa PEPC polypeptide (p107). Immunoblotting with an anti-(phosphosite specific)-IgG indicated enhanced phosphorylation of p107 occurred at

its conserved N-terminal seryl phosphorylation site during Pi starvation of the suspension cells or seedlings. Semi-quantitative RT-PCR revealed that AtPpc1 (At1g53310, 1 of 4 Arabidopsis PEPC genes) was the only PEPC gene transcriptionally upregulated by the –Pi cell cultures. Approximately 2 mg of PEPC was purified to near homogeneity (Sp. act. = 22.3 units•mg-1) from 240 g of –Pi suspension cells. MALDI-qTOF MS/MS, gel filtration, SDS-PAGE, and immunoblotting demonstrated that the final preparation exists as a 440-kDa AtPPC1 homotetramer composed of phosphorylated 107-kDa subunits. However, Pi-affinity PAGE using Phos-tag acrylamide (www.phos-tag.com) and kinetic studies (± λ phosphatase treatment) indicated sub-stoichiometric phosphorylation of the final AtPPC1 preparation. Although the significance of in vivo PEPC phosphorylation during Pi stress remains to be established, our results demonstrate that AtPPC1 is induced and phosphorylated by -Pi Arabidopsis. P-49 Antidiabetic properties of selected mexican copalchis of the Rubiaceae family José A Guerrero-Analcoa,c, O Medina-Camposa, F Brindisa, R Byeb, J Pedraza-Chaverria, A Navarretea, and R Mataa aFacultad de Química, and bInstituto de Biología, Universidad Nacional Autónoma de México, México DF, 04510, México; cFaculty of Science, University of Ottawa, Ottawa, ON, Canada, K1N 6N5 jguerre2@uottawa.ca, janton_guerrero@yahoo.com.mx, rachel@servidor.unam.mx The extracts prepared from the stem barks of several Mexican copalchis species, including Hintonia latiflora, H. standleyana, Exostema caribaeum and a commercial mixture of H. standleyana and E. caribaeum (CM) showed significant hypoglycemic and antihyperglycemic effects. The extracts were tested in three different in vivo models using normal and streptozotocin (STZ)-induced diabetic rats. From the active extract of H. latiflora, 25-O-acetyl-3-O-β-D-glucopyranosyl-23, 24-dihydrocucurbitacin F (1), an analog of 23,24-dihydrocucurbitacin F, and several known compounds (2-8) were isolated. Oral administration of H. latiflora and H. standleyana extracts [100 mg/Kg of body weight (bw) each] and 5-O-β-D-glucopyranosyl-7,3′,4′-trihydroxy-4-phenylcoumarin (5) (30 mg/Kg of bw) to STZ-induced diabetic rats, for a 30 day duration, restored blood glucose levels to normal values. The groups treated either with the active principle 5, or the extracts from the species of Hintonia genus, showed less body weight loss than glibenclamide-treated and diabetic control groups (p < 0.05). It was also demonstrated that the extract of H. latiflora regulated hepatic glycogen and plasma insulin levels (p < 0.05). These data suggest that its antihyperglycemic effect is due in part to stimulation of insulin secretion and regulation of hepatic glycogen metabolism. Supported by a grant of CONACYT (C01-018).

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P-50 Genomic and proteomic studies of the maize response to Fusarium graminearum Linda Harris, W Bosnich, D Schneiderman, A Johnston, A Saparno, S Gleddie, and N Tinker ECORC, Agriculture and Agri-Food Canada, 960 Carling Ave, Ottawa, ON, Canada, K1A 0C6 harrislj@agr.gc.ca The fungal pathogen Fusarium graminearum causes gibberella ear rot in maize ears and contaminates grain with mycotoxins. To understand how resistant and susceptible maize plants respond to F. graminearum attack, we are studying maize gene and protein expression during the early infection process. Using a 55K oligomer maize microarray, gene expression profiling was performed on kernel tissues, comparing mock- and F. graminearum field-inoculated tissues from susceptible and resistant inbreds 6 and 48 hours post-inoculation collected over three seasons. We also used a non-gel-based shotgun proteomics method (iTRAQ) to survey the proteomes of the same samples at 48 hours post-inoculation. Generally, we observe that the susceptible and resistant inbreds exhibit a similar pattern of infection-induced gene and protein expression. Realtime-PCR is being used to validate the microarray results of genes of interest. Future studies will assess the association of specific genes with resistance in recombinant inbred populations with the goal of providing biomarkers for gibberella ear rot resistance. P-51 A novel series of plant growth promoting rhizobacteria (PGPR) to plant signals: Bacteriocins and their direct plant growth promoting effects Xuefeng He, F Mabood, X Zhou, A Souleimanov, and DL Smith 21,111 Lakeshore Road, Ste-Anne-de- Bellevue, QC, Canada, H9X3V9 xuefeng.he@mail.mcgill.ca Plant growth promoting rhizobacteria (PGPR) are bacteria that can colonize plant root systems and increase plant growth either directly or indirectly. Plants and PGPR communicate with each other by using a variety of signal molecules. These signal molecules are detected by the appropriate partner and lead to a number of physiological responses. Bacteriocins are small peptides produced by many bacteria and have bactericidal effects on microorganisms closely related to the producer strain. We have recently isolated three new bacteriocins produced by PGPR. These are Thuricin 17 (Bacillus thuringiensis NEB17), Bacthuricin F4 (Bacillus thuringiensis subsp. kurstaki), and Cerecin 85 (Bacillus cereus UW85). Initial studies have shown that all these bacteriocins, at very low concentrations (10-9-10-11 M), can promote seed germination, seedling emergence, and early seedling growth under growth chamber conditions of a range of crops. Further study shows that these bacteriocins can also help crops to resist some abiotic stresses such as low temperature and high salinity.

P-52 New pathways associated with aluminum stress and tolerance are identified using microarrays in wheat A Oury-Diallo and Mario Houde Dép des sciences biologiques, Université du Québec à Montréal, CP 8888, Succ Centre-ville, Montréal, QC, Canada, H3C 3P8 houde.mario@uqam.ca Aluminum is considered the most limiting factor for plant productivity in acidic soils, which cover large areas of the world’s potential arable lands. The most important effect of Al toxicity is the reduction of root growth. In this study we used microarrays to identify genes associated with Al stress and tolerance in four different wheat lines treated with Al concentrations causing the same root growth inhibition. Microarray expression profiling identified 83 candidate genes associated with Al stress and 25 associated with Al tolerance. Ten genes were selected for qRT-PCR validation (4 among the stress-associated candidates and 6 among the tolerance-associated candidates). In addition, four different Al concentrations were used varying from 0 to 250 µM Al to increase our understanding of the gene expression responses to Al exposure. Most of the genes associated with tolerance are up-regulated by Al and include known genes such as glutathione S-transferase, germin/oxalate oxidase, cytochrome P450 mono-oxygenase, pathogen response endopeptidase inhibitor, fructose 1,6-bisphosphatase, cellulose synthase, zinc finger transcription factor and disease resistance response protein. Some of stress and tolerance associated genes may play roles in maintaining energy supply for the detoxification of reactive oxygen species and help maintain the ascorbate levels needed for cell wall loosening and root growth. Three genes are more expressed in the sensitive cultivars suggesting that they may be negative regulatory factors of root growth. P-53 The wheat CBF gene family: evaluating tissue and cellular expression specificity Che Hua and J Danyluk Dép des sciences biologiques, Université du Québec à Montréal, CP 8888, Succ Centre-ville, Montréal, QC, Canada, H3C 3P8 danyluk.jean@uqam.ca The study of cold-regulated genes and transcription factors interacting with their promoters has revealed that the CBF family plays a central role in their regulation. Phylogenetic and bioinformatic analyses of CBF genes from wheat and other cereals reveal that wheat contains up to 25 different genes, and that monocot CBF proteins can be subdivided into at least 10 groups displaying specific structural characteristics. Six of these groups (total of 18 genes) have evolved quite recently since they are specifically found in the cereal subfamily Pooideae. The conservation of all these CBF genes in present day wheat species could suggest the acquisition of different or complementary functions. With the long term goal of understanding the functions of the different members of this family in wheat, we set out to determine their tissue and cellular expression specificities. An optimized in situ hybridization protocol allowed us to detect CBF expression in 20ºC grown plants. Preliminary characterization of two CBF genes shows that

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compared to control plants, cold treatment increases their quantitative expression but not their spatial distribution. In addition, the results reveal that the developmental state of a tissue has an important impact on the quantitative expression of CBFs in a given cell type. These results will be discussed in relation to the development of cold tolerance in these cells and tissues. Understanding the specific and synergistic roles of this multigene family will help to provide the basis for effective engineering strategies leading to greater cold tolerance. P-54 Adenylate kinase equilibrium optimizes photosyn-thesis: applications for metabolomic research Abir U Igamberdiev1 and LA Kleczkowski2 1Dept of Biology, Memorial University of Newfoundland, St. John’s, NL, Canada, A1B3X9; 2Dept of Plant Physiology, Umeå Plant Science Centre, University of Umeå, 90187 Umeå, Sweden igamberdiev@mun.ca Metabolic fluxes are optimized in photosynthetic plant cells in a way that they are stable and robust. A major mechanism of achieving such a stable non-equilibrium state is “thermodynamic buffering” via high activities of equilibrating enzymes such as adenylate kinase (AK). Under the stable non-equilibrium, the ratios of free and Mg-bound adenylates (ATP, ADP and AMP) and the concentration of free Mg are maintained at the interdependent levels equilibrated with the values of intraorganellar membrane potentials. The set of these ratios/concentrations constitutes the generalized energy/redox charge of the cell and determines the rates of major metabolic fluxes. These parameters are computationally linked to concentrations of other nucleotide cofactors and cations. The major factor for generation of computability is the activity of AK in the intermembrane spaces (IMS) of mitochondria and chloroplasts. From the AK equilibrium, [Mg2+] in the IMS of chloroplasts and mitochondria is calculated as 0.4–0.5 mM and in the cytosol as 0.2–0.3 mM, whereas the MgATP/MgADP ratio in the IMS and cytosol is 6–9 and 10–15, respectively. These represent optimal conditions for transport of adenylates (via the maintenance of an ATPfree/ADPfree ratio close to 1) and mitochondrial respiratory and chloroplast photosynthetic rates (via the maintenance of submillimolar [ADPfree] in the IMS). This, in turn, drives regulation of the protein phosphorylation rate and allosteric regulation of major enzymes (via changes in the MgATP/AMPfree ratio). It is concluded that the phenomenon of optimization of metabolic fluxes via thermodynamic buffering results in their computability and becomes a general prerequisite of stable operation of complex biological structures making them possible to maintain a high integrity and adapt to changing environmental conditions. This provides a far-reaching application for calculating major metabolic cellular parameters in the metabolomic research. P-55 Genetic diversity in soybean: a tale of two germplasm sets Iquira E and Belzile F Rue de la Médecine, Pavillon C-E Marchand, local 1245, Université Laval, QC elmer.iquira.1@ulaval.ca

Soybean, Glycine max (L.) Merr., originated in China. Accordingly, the greatest genetic diversity for this species is found in Asia. In contrast, in North America, soybean cultivars trace back to a small number of plant introductions from Asia and genetic diversity is typically quite limited (Singh and Hymowitz, 1999, Cui et al. 2001, Li et al. 2002). The purpose of this work was to measure and compare the genetic diversity in two sets of soybean lines. The first set (termed “local”) is composed of 100 lines used in a private breeding program in Quebec and the second set (termed “exotic”) is composed of 200 lines from elsewhere in the world (but mostly from Asia) and included a few lines of G. soja, the wild progenitor of cultivated soybean. All the genotypes belonged to maturity groups between 000 and II. A total of thirty-nine microsatellites (SSRs) were used to genotype the two collections. The number of alleles per locus was almost twice as great in the “exotic” set compared to the “local” set. Also, the number of “unique” alleles, i.e. those uniquely present in one set and absent in the other, was almost five fold greater (193 vs 39) in a subset of 108 exotic lines with good adaptation than among the “local” set. A genetic distance matrix (as per Nei and Li, 1979), a UPGMA cluster analysis and a principal coordinate analysis were conducted based on the SSR data. These analyses all indicated that the “exotic” set was much more diverse and formed a clearly distinct group from the “local” set. Interestingly, some of the lines showing the best adaptation to local conditions were quite distinctive in terms of their genotype and could potentially contribute useful novel genetic variation within the breeding program. P-56 Detoxification of mycotoxin deoxinivalenol by soil bacteria Islam, MR1, Zhou T2, and Pauls KP1 1Dept of Plant Agriculture, University of Guelph; and 2Guelph Food Research Center, AAFC, Guelph, ON, Canada mislam@uoguelph.ca Deoxinivalenol (DON, vomitoxin) is a mycotoxin produced in cereals by the infection of Fusarium species. DON inhibits eukaryotic protein biosynthesis and also acts as a virulence factor duing fungal pathogenesis. The aim of this study was to isolate and chracterize DON detoxifying bacteria from soil. We screened soil samples collected from various locations of Ontario and analyzed their DON degradation ability by high performance liquid chromatography (HPLC). The effects of five factors (growth medium, inoculums size, pH, incubation time and temperature) on biodegradation of DON were investigated. Cultures from one of the soil samples exhibited complete (100%) DON degradation activity on mineral salts broth (MSB) supplemented with 0.5% bacto peptone at pH 7 after 3d of incubation at 25oC. To facilitate the isolation of a pure culture, the mixed bacterial culture was sub-cultured on MSB in presence of several antibiotics. After several transfers into MSB with antibiotics microbial diversity was analyzed by terminal fragment length polymorphism (T-RFLP) method. Cultures treated with 100 ppm penicillin and cyclohexamide/dichloramphenicol reduced bacterial diversity without affecting any DON degradation activity. Liquid-chromatography-ultraviolet–mass spectrometric (LC-UV-MS) analysis determined the degraded product as de-epoxy DON (also known as DOM-1), which is a

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significantly less toxic metabolite than DON. Isolation of the pure culture of the active bacterium is in progress. This research will help in finding a source of DON detoxifying novel gene. Eventually, cloning and transfer of this gene into a cereal genome could potentially reduce the DON toxicity and disease severity in Fusarium infested cereals. P-57 Effects of low temperature stress on excitation energy partitioning and photoptotection in Zea mays L. Alexander G. Ivanov2, L Gudynaite-Savitch2, NPA Huner2, J Simmonds1, LV Savitch1 1Agriculture and Agri-Food Canada, ECORC, Ottawa, ON, Canada, K1A 0C6; 2 Dept of Biology, University of Western Ontario, London, ON, Canada, N6A 5B7 aivanov@uwo.ca; loreta.gudynaite-savitch@iogen.ca; nhuner@uwo.ca; simmondsja@agr.gc.ca; savitchl@agr.gc.ca Analysis of the partitioning of absorbed light energy within PSII into fractions utilized by PSII photochemistry (ΦPSII), thermally dissipated via ∆pH- and zeaxanthin-dependent energy quenching (ΦNPQ) and a constitutive non-photochemical energy losses (Φf,D) was performed in control and cold stressed maize leaves. The estimated energy partitioning of absorbed light to various pathways indicated that the fraction of ΦPSII was 2-fold lower, while the proportion of thermally dissipated energy through ΦNPQ was only 30% higher in cold stressed than in control plants. In contrast, Φf,D, i.e. the fraction of absorbed light energy dissipated by additional quenching mechanism(s) was 2-fold higher in cold stressed leaves. Thermo-luminescence measurements revealed that the changes in energy partitioning were accompanied by narrowing of the temperature gap (∆TM) between S2/3QB- and S2QA- charge recombinations in cold stressed leaves to 8°C compared to 14.4°C in control maize plants. These observ-ations suggest an increased probability for alternative non-radiative P680+QA- radical pair recombin-ation pathway for energy dissipation within the reaction centre of PSII in cold stressed maize plants. This additional quenching mechanism might play an important role for thermal energy dissipation and photoprotection when the capacity for the primary, photochemical (ΦPSII) and zeaxanthin-dependent non-photochemical quenching (ΦNPQ) pathways are thermodynamically restricted in maize leaves exposed to cold temperatures. P-58 Microtubule disruption up-regulates the triterpene synthase MRN to reduce root elongation in Arabidopsis Eric E Johnson* and G Wasteneys University of British Columbia, 3529-6270 University Blvd, Vancouver,BC,Canada,V6T1Z4 ericjohn@interchange.ubc.ca Various developmental processes and stress cues require or induce changes in microtubule dynamics. It has been suggested that the change in microtubule dynamics plays a role in the transcriptional regulation of developmental or stress responsive genes. To investigate this possibility, a microarray analysis was conducted to profile differential gene expression arising as a result of

microtubule disruption in the temperature-sensitive mor1-1 mutant. In this mutant, microtubule dynamics are greatly reduced at the 31°C restrictive temperature. MARNERAL SYNTHASE (MRN) was found to be the most highly up-regulated gene within 4 hours of shifting the temperature to 31°C. Little is known about the function of this triterpene synthase, or the triterpenoid product marneral. The goal of this study was to identify the function of MRN by phenotype analysis of the T-DNA insertion mutant mrn-1 and to clarify which signal transduction pathways are turned on in response to reduced microtubule dynamics. Previous studies have demonstrated that the effects on root growth of the hormones ethylene and cytokinin are modified by the addition of sucrose. Using our normal growth medium containing 3% sucrose, we found that mrn-1 mutant roots were shorter than wild-type roots at day 3 post-germination but showed no differences by day 8. In the absence of sucrose, mrn-1 and wild-type roots were equivalent in length at day 3 and significantly longer than wild-type roots at day 8, suggesting that MRN is required to limit root growth when sucrose availability is limited. The addition of kinetin rescued the mrn-1 phenotype in sucrose-free medium suggesting that MRN acts upstream and possibly independently of cytokinin to inhibit root elongation. Wild-type and mutant root growth was inhibited equally by the addition of the ethylene precursor ACC but addition of AgNO3, an ethylene action inhibitor, stimulated the production of relatively short mrn-1 roots and relatively long wild-type roots. While the effects of mrn-1 on the ethylene pathway are apparent, an exact role for MRN in ethylene signalling remains unclear. P-59 Approaches for genetic transformation of peach. A Kalinina, R Chapman, D Cuppels, A Zoina, and DCW Brown Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, London, ON, Canada, N5V4T3; (AZ) Dipartimento ArBoPaVe, Università di Napoli Federico II, Portici NA, Italy, 80055 kalininaa@agr.gc.ca Peach [P. persica L. (Batsch)] is considered to be a recalcitrant woody species for Agrobacterium-mediated transformation. Peach is also difficult to manipulate in vitro, and in vitro responses appear highly genotype dependant. Recently, we established a regeneration system based on organogenesis of stem segments. Investigation with this system led to the observation that conventionally engineered Agrobacterium strains did not appear to infect a wide range of peach tissues due to Agrobacterium cell lysis. Preliminary analysis of metabolite profiles of peach tissues showed very high accumulation of phenolic compounds which we speculate might interfere with Agrobacterium infection. We found that Agrobacterium strains naturally pathogenic to peach appeared to overcome this infection barrier. Transformants expressed both reporter genes and oncogenes and resulted in visible gall formation without shoot regeneration. A new transformation strategy including selected Agrobacterium strains re-engineered for resistance to peach will be discussed.

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P-60 Isolation of defensin protein; PDC1 from maize (Zea mays L.) and its antifungal activity against Fusarium graminearum Pragya Kant, Wen-Zhe Liu, P Masliamany, J-Z Yuan, J Liu, and KP Pauls Dept of Plant Agriculture, University of Guelph, ON, Canada, N1G 2W1 pkant@uoguelph.ca Plant defensins are small antimicrobial, basic peptides that have a characteristic three-dimensional folding pattern which is stabilized by eight disulphide-linked cysteines. We have cloned a maize defensin gene (pdc1) and have characterized that it possess antifungal activity against Fusarium graminearum. A 545 bp fragment was amplified from genomic DNA of maize with the primers designed from a barley defensin EST. The cloned genomic DNA fragment sequence contains a 249 bp open reading frame, 102 bp intron, and 194 bp untranslated region. The deduced PDC1 protein consists of 82 amino acids, including a signal sequence of 35 amino acids and defensin domain of 47 amino acids containing 8 cysteines. The protein sequence has homology to γ2-zeathionin defensins. The defensin protein was expressed in two systems (E. coli and yeast Pichia pastoris), which differ in their ability to catalyze disulphide bond formation that stabilizes the 3-D structure of protein. PDC1 purified from P. pastoris was more effective against F. graminearum than the protein expressed in E. coli in the antifungal assays. In addition, the removal of His-tag used for the purification increased the fungicidal activity of PDC1 protein. Our results suggest that the overexpression of the defensin gene may be a useful strategy for producing cereal crops with resistance against F. graminearum. P-61 Does inoculation with nitrogen-fixing bacteria enhance nitrogen use efficiency and energy ratios of biofuel grasses? Keomany Ker1,2, JW Fyles2, and DL Smith1 1Dept of Plant Science and 2Dept of Natural Resource Sciences, McGill University, 1111 Lakeshore Drive, Ste-Anne-de-Bellevue, QC, Canada, H9X 3V9 keomany.ker@mail.mcgill.ca Perennial rhizomatous (PR) grasses, such as Miscanthus, switchgrass and reed canarygrass, are high-yielding biomass crops that are especially useful for ethanol production via cellulose fermentation or as direct combustibles to be used for heat and electricity. Once established, their perennial nature, rapid growth, and low mineral content make it desirable for biofuel production. In particular, Miscanthus has garnered considerable interest as a biofuel feedstock, in part due to its sterility, large energy ratios and its low response to nitrogen (N), suggesting that it may have an alternate N source, perhaps through biological nitrogen fixation (BNF) from associative free-living diazotrophs and other plant growth promoting rhizobacteria (PGPR) (Heaton et al. 2004, Lewandowski and Schmidt 2006). Although isolation of diazotrophs from Miscanthus have been reported (Kirchhof et al. 2001), few research have studied the degree to which N2-fixing bacteria contribute N for growth, and if BNF plays a substantial role in enhancing nitrogen use efficiency (NUE), and thereby yield and energy ratios of

these grasses. The purpose of this project is to investigate and determine the suitability of PR grasses for biofuel production in southwestern Québec. A side-by-side field comparison of productivity with Miscanthus x giganteus, switchgrass (Panicum virgatum) and reed canarygrass (Phalaris arundinacea) will be conducted. In addition, we will investigate possible associations with N2-fixing soil bacteria and whether inoculation with these bacteria or other PGPR increases yield, NUE and energy ratios of PR grasses. Heaton et al. 2004. Biomass and Bioenergy 27: 21-30; Kirchhof et al. 2001. International Journal of Systematic and Evolutionary Microbiology 51: 157-168; Lewandowski and Schmidt. 2006. Agriculture, Ecosystems and Environment 112: 335-346. P-62 Genetic and physiological analyses of Thellungiella salsuginea in response to low temperatures Khanal N1, Li Y2, Moffatt B2, and Gray GR1 1Dept of Plant Sci, University of Saskatchewan, Saskatoon, SK, S7N 5A8; 2Dept of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada nik370@mail.usask.ca Thellungiella is a crucifer which is extremophyllic (halophytic) in nature. By virtue of its extremophillic properties, Thellungiella has been proposed as an alternative model plant for the elucidation of abiotic stress tolerance. We have utilized genetic and physiological approaches to examine the responses of this plant to low temperature. Two different ecotypes of Thellungiella (Yukon and Shandong) as well as Arabidopsis were grown under 20/10°C (light/dark) temperatures at 250 µmol photons m-2 s-1 PPFD with a 21 h light/dark cycle. For cold acclimation studies, plants were shifted to a 5/5°C (light/dark) regime with all other conditions constant. Dark respiration of non-acclimated and cold acclimated plants of all three species/ecotypes was determined and unit leaf rate was calculated as a proxy measure of net assimilation rate. The results showed 1.6- to 1.7-fold higher rates of dark respiration in Yukon than both Shandong and Arabidopsis non-acclimated plants respectively. This resulted in a lower net assimilation rate for Yukon in comparison to Shandong and Arabidopsis. Cold acclimation resulted in a 68 and 79% decrease in dark respiration for Shandong and Yukon respectively. However, only an 18% decrease in Arabi-dopsis was observed resulting in this species having a 2.4- to 2.8-fold greater rate of dark respiration in comparison to Thellungiella. These results are consistent with the growth pattern of these plants in both non-acclimating and cold acclimating conditions. In addition, these 3 species/ ecotypes displayed an increasing gradient of growth with increasing irradiance from 100 to 450 µmol photon m-2 s-1 PPFD, but the light responses were more pronounced in Yukon ecotype. We have investigated these changes at the molecular level using a previously developed array of stress-induced Thellugiella cDNAs. This was probed with RNA isolated from control, 24h, 1-, 2- and 3-week cold-treated Yukon plants, using only tissue from leaves that had developed in the cold conditions for the latter three treatments. The results indicate only modest differences between the two ecotypes but are consistent with changes in respiration-associated genes are important. The role of respiration in the light as it pertains to cold acclimation between the Yukon and Shandong ecotypes will be discussed.

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P-63 Cloning and analysis of the promoter of a low affinity sulfate transporter (LAST) in Brassica juncea B Turnbull, C Woodhouse, Justin Kicks, and SM Aitken Dept of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada, K1S 5B6 susan_aitken@carleton.ca Phytochelatins are cysteine-rich peptides involved in the chelation and sequestration of heavy metals by plants. While the biosynthetic pathway of phytochelatins has been determined, their role in the ability of hyperaccumulator species to tolerate and accumulate heavy metals is not fully understood. Brassica juncea is a model organism for phytoremediation applications and in the study of the underlying mechanism(s) of heavy metal hyperaccumulation. Expression of the low affinity sulfate transporter (LAST), which is thought to play a role in sulfate transport within the plant, has been reported to be responsive to cadmium exposure. In this study, a 4-Kbp segment of the LAST promoter region was cloned, sequenced, and analyzed. A number of unique and relevant putative cis-acting elements were identified, including a recently-reported heavy-metal response element, which are not present in the corresponding sequence of the closely-related, non-hyperaccumulator, A. thaliana. Promoter-reporter constructs, expressing the GUS reporter gene under the control of the full-length sequence and a series of truncated versions of the LAST promoter region, were created and introduced into A. thaliana via Agrobacterium-mediated transformation. A set of 10 transgenic A. thaliana lines were successfully created using the reporter construct bearing the full-length LAST promoter. Analysis of these transgenic A. thaliana lines will enable the investigation of the effect of cadmium exposure on LAST expression throughout the plant. P-64 Genome-wide analysis and light regulation of the chalcone synthase multigene family in the moss Physcomitrella patens PKH Koduri, D-Y Suh*, E Barker, and N Ashton Dept of Chemistry and Biochemisty; and Dept of Biology, University of Regina, Regina, SK, Canada, S4S 0A2 Suhdaey@uregina.ca / phanikko@uregina.ca Enzymes of the chalcone synthase (CHS) superfamily catalyse the production of a variety of secondary metabolites in bacteria, fungi and plants. It is generally accepted that some of these secondary metabolites have played an important role during the early evolution of land plants by providing protection from various environmental assaults including UV irradiation. The genome of the moss, Physcomitrella patens, incorporates a chs multigene family comprising 19 putative chs genes, of which at least 10 are expressed. Our bioinformative and biochemical analyses showed that these genes likely encode different enzymes belonging to the CHS superfamily. Chs8, chs9 and chs11 are especially intriguing since they appear to encode non-CHS enzymes that may be ancestral to plant CHS enzymes. Additionally, our study of Physcomitrella chs genes is providing insights into their evolutionary expansion, functional diversification and regulation. For example, from phylogenetic reconstructions coupled with linkage data,

we have mapped the most probable path of chs gene duplications. Thus, the moss may well be an 'archaeological dig' for the study of evolution and functional divergence of the plant CHS superfamily. Comparative analysis of Physcomitrella chs nucleotide and CHS amino acid sequences together with those from other plants has enabled us to infer plausible gene models for the moss genes and to annotate them. Within the moss chs genes, we have identified cis-acting elements (G-box, W-box, etc) that are known to be involved in regulating higher plants chs genes. We are using these discoveries as a platform for the further investigation of chs gene structure, duplication pattern, phylogeny, and control in the moss Physcomitrella. P-65 Leucine-rich repeat-associated motif at the root of arbuscular mycorrhiza and rhizobial symbioses Sonja Kosuta, M Held, G Morieri, C Johansen, B Karas, A Macgillivary, A Downie, G Oldroyd, and K Szczyglowski Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON, Canada Phenotypes that are associated with mutant alleles can be used to gain insight into the structure and function of specific protein domains. Here, we present a symRK allele with a novel symbiotic phenotype. The symRK-14 mutation causes a single amino acid change, P to T, in the GDPC motif just upstream of the first leucine-rich repeat (LRR) region of the extracellular (EC) domain. Root hairs respond to inoculation with Rhizobium bacteria by exaggerated curling and initiation of nodule primordia, however bacterial infection thread formation is blocked. Symbiotic entry of arbuscular mycorrhizal fungi is also blocked, suggesting a specific role for SYMRK in intracellular accommodation of symbiotic microbes. The GDPC motif is highly-conserved in evolutionarily-divergent plants, including moss and liverwort, indicating that this motif has an ancient origin in a common ancestor to all land plants. Furthermore, we found that the GDPC motif is conserved in 62 of over 200 LRR-receptor kinases in Arabidopsis, suggesting additional functional significance outside of symbiosis. The evolutionary implications of this intriguing new motif and its possible role in symbiosis and LRR-RLK function will be discussed. P-66 Promoter analysis of a subfamily of calmodulin-like genes in Arabidopsis LK Koziol and WA Snedden Queen's University, Kingston, ON, Canada, K7L 3N6 2lkk@queensu.ca Ca+2 ions participate as second messengers in many stress-response and developmental pathways. Among eukaryotes, plants possess a remarkable diversity of Ca2+ binding proteins (Ca2+ sensors) such as calmodulin (CaM) and CaM-related proteins (CMLs) that regulate downstream targets and coordinate signal transduction events in response to stimuli. We have been studying a small subfamily of CMLs (CML37, CML38, CML39) in Arabidopsis that show a dramatic induction of expression in response to environmental stress. In order to understand

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the underlying regulatory mechanisms of these genes, we have been conducting promoter analysis experiments using 5’-upstream regions of the CMLs to drive GUS reporter expression. This empirical approach is a critical complement to algorithm-based prediction methods. Delineation of the relevant cis-elements should lay the groundwork to identify the transcriptional regulators that direct stress-responsive CML gene expression. Our data reveal clear developmental, tissue and stimulus-specific patterns of expression among these three CMLs. CML37 and CML38 respond very strongly to mechanical wounding but not herbivory by cabbage moth larvae (Pieris rapae) whereas CML39 is less responsive to wounding but is induced significantly by jasmonate. We have identified negative regulators in the promoter regions of CML37 and CML38 and analysis is ongoing to determine whether these are the major elements controlling wound response or whether positive regulatory elements also contribute. P-67 Isolation of an embryogenic line from non-embryogenic Brassica napus cv. Westar through microspore embryogenesis MR Malik1, F Wang1,2, JM Dirpaul1, N Zhou1,3, J Hammerlindl1, W Keller1, SR Abrams1, A MR Ferrie1, and Joan E Krochko1 1Plant Biotechnology Institute, National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9; Current addresses: 2 National Institute for Nano-technology NRC of Canada, 11421 Saskatchewan Dr, Edmonton, AB, Canada, T6G 2M9; 3 Dow AgroSciences, 9330 Zionsville Rd, Indianapolis, IN, USA 46268 joan.krochko@nrc-cnrc.gc.ca Brassica napus cultivar Westar is non-embryogenic under all standard protocols for induction of microspore embryogenesis; however, the rare embryos produced in Westar microspore cultures (induced with added brassinosteroids) were found to develop into heritably-stable embryogenic lines after chromosome doubling. One of the Westar-derived doubled haploid lines, DH-2, produced up to 30% the number of embryos as the highly embryogenic B. napus line, Topas DH4079. Expression analysis of marker genes for embryogenesis in Westar and the derived DH-2 line, using real-time RT-PCR, revealed that the timely expression of embryogenesis-related genes such as LEAFY COTYLEDON1 (LEC1), LEC2, ABSCISIC ACID INSENSITIVE3, and BABY BOOM1, and an accompanying down-regulation of pollen-related transcripts, were associated with commitment to embryo development in B. napus microspores. Microarray comparisons of 7d cultures of Westar and Westar DH-2, using a B. napus seed-focused cDNA array (10,642 unigenes; http://brassicagenomics.ca) identified highly-expressed genes related to protein synthesis, translation and response to stimulus (GO Ontology) in the embryogenic DH-2 microspore-derived cell cultures. By contrast, transcripts for pollen-expressed genes were predominant in the recalcitrant Westar microspores. Besides being embryogenic, DH-2 plants showed alterations in morphology and architecture as compared to Westar, for example, epinastic leaves, non-abscised petals, pale flower colour, and longer lateral branches. Auxin, cytokinin and ABA profiles in young leaves, mature leaves and inflorescences of Westar and DH-2 revealed no significant differences that could

account for the alterations in embryogenic potential or phenotype. Various mechanisms accounting for the increased capacity for embryogenesis in Westar-derived DH lines are considered. P-68 Improvement of source-sink strength by genetic manipulation of ADP-glucose pyrophosphorylase activity in winter wheat (Triticum aestivum cv. McClintock) Mohamed Koronfel, Y Sun, A Brûlé-Babel, and F Razem University of Manitoba, 222 Agriculture Bldg, 66 Dafoe Rd, Winnipeg, MB, Canada, R3T 2N2 koronfel@cc.umanitoba.ca

The extent of plant productivity and crop yields are largely determined by the capacity of source leaves to photosynthesize and fix CO2 and the capacity to assimilate this fixed carbon by sink tissues and organs. In cereal crops such as wheat, the overall productivity is largely limited by the sink's capacity to convert sugars into starch. If developing grains during filling are unable to accommodate available sucrose, this metabolite builds up in leaf cells preventing Pi from being recycled. This results in a decreased photophosphorylation and subsequently the net CO2 fixation significantly decrease. In search for factors that could affect source-sink strength, it has been reported that the manipulation of the ADP-glucose pyro-phosphorylase (AGPase) has significant effect on CO2 fixation and overall starch accumulation in sink tissues. AGPase is the first committed enzyme in starch biosynthesis and its activity is often limited by Pi and 3-phosphogylecerate (3PGA). Current efforts in our lab- oratory are directed at manipulating leaf and grain AGPase to alleviate CO2 fixation and assimilation with the aim to increase sink strength and overall starch biosynthesis. We implement tissue-specific expression of AGPase gene previously mutated to circumvent inhibition by Pi and the need for 3PGA activation. Here we report our progress to date on the manipulation of source-sink strength in wheat by the over-expression of a mutated AGPase from heterologous sources.

P-69 Ovule development and pollen tube guidance are affected in the Solanum chacoense MAPKKK ScFRK1 mutant Edith Lafleur, C Daigle, and DP Matton IRBV, Dép de Sciences biologiques, Université de Montréal, 4101, rue Sherbrooke est, Montréal, QC, Canada, H1X 2B2 edith.lafleur@umontreal.ca Solanum chacoense Fertilization-Related Kinase 1 is a member of the MEKK subfamily of plant MAPKKK that is specifically expressed in ovules. ScFRK1 mRNA levels decrease rapidly following pollination and accumulate predominantly in the egg apparatus cells of the embryo sac at mature stage. These results suggest both pre- and post-fertilization roles in ovule development. Transgenic plants down regulated in ScFRK1 expression showed no abnormal phenotypes in vegetative tissues but produced seedless fruits upon pollination. To determine if aberrant ovule development caused this seedless phenotype,

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cleared flower buds at various developmental stages from affected transgenic lines were observed by DIC microscopy. Formation of the female gametophyte did not progress further than the functional megaspore stage (FG1) in affected transgenic lines, leading to the formation of ovules devoid of an embryo sac. Surprisingly, even in severely affected plants producing no or very few embryo sacs, pollination led to the production of parthenocarpic fruits. Since embryo sac integrity is a prerequisite for pollen tube guidance, we devised a semi in vivo pollen tube growth system to assess the ability of the ScFRK1 mutant ovules to attract pollen tubes. As expected, guidance was severely affected, confirming the involvement of the egg apparatus cells as the source of attracting molecules. Attraction was also determined to be highly species-specific and developmentally regulated with the acquisition of attraction competence on anthesis day. P-70 The role of CML42 in trichome branch formation in Arabidopsis Lam P, Dobney S, and WA Snedden Queen’s University, Kingston, ON, Canada, K7L 3N6 3ywl@queensu.ca Trichomes are branched, unicellular structures that serve as a model for the study of cell morphogenesis. The current literature suggests that there are multiple genes that regulate trichome branching. We have been studying CML42, a Ca2+-binding Arabidopsis protein related to the prototypical Ca2+ sensor, calmodulin (CaM). A CML42 T-DNA insertion line (cml42) exhibits a mutant trichome phenotype with increased branch numbers compared to wild-type plants. Various biochemical analyses demonstrated that recombinant CML42 binds Ca2+ which results in a conformational change and the exposure of hydrophobic regions. CML42 promoter analysis using a GUS reporter demonstrated that CML42 is widely expressed, most notably in specialized support cells found at the base of trichomes. Yeast-2-hybrid and GST-pull down analysis suggest that CML42 interacts with a protein termed KIC (kinesin interacting calcium-binding protein). Consistent with our findings, previous work has implicated KIC in trichome morphogenesis through its regulation of the motor-domain protein, kinesin (KCBP). Like CML42 mutants, both KIC and KCBP mutants show mutant trichome phenotypes. Our genetic studies imply that CML42 is a negative regulator of trichome branching. It is possible that CML42 interacts with KIC under certain Ca2+ concentrations to form a multiprotein complex with KCBP that mediate trichome morphogenesis. Current studies are examining the interaction between CML42 and KIC to determine the peptide region of physical binding, affinity, and the role of Ca2+ in the association. In addition, we recently isolated a KIC T-DNA insertion line and are assessing it for altered trichome morphology. Collectively our data support the important role of Ca2+ signaling in trichome branching and structure. P-71 Comparative analysis of genetic diversity in canadian barley assessed by SSR, DArT and pedigree data M Lamara and F Belzile m_lamara@yahoo.fr

Domestication and, more recently, modern plant breeding have contributed to important reductions in genetic diversity in many crops and this increased homogeneity may be detrimental in responding to challenges posed by both pathogens and rapidly changing climate (Asins and Carbonell, 1989). It is thus important to measure, maximize and exploit as well as possible the genetic diversity in plant breeding programs. The aims of this study were to measure genetic diversity and population structure among 120 Canadian barley cultivars using two types of molecular markers (SSRs and DArTs) and pedigree data. A total of 368 alleles were identified at 50 SSR loci. The number of alleles per locus ranged between 2 and 13, (x = 7.36) and PIC values ranged from 0.64 to 0.78 (x = 0.69). Clustering of genotypes was performed based on the genetic distance matrix and the dendrogram obtained showed the genetic relationships among barley cultivars. For the biallelic DArT markers, the genetic distance matrix was based on 971 markers whose PIC values ranged between 0.06 and 0.50 (x = 0.39). Similarly, this genetic distance matrix was used to produce a DArT dendrogram. A third distance matrix was computed based on the kinship coefficient and was used to produce a third dendrogram. The topological similarity of the three dendrograms was estimated using a congruence index (as per Vienne et al., 2007) and showed that the three dendrograms are in very good agreement. Statistical analyses also showed a highly significant correlation between the SSR and DArT matrices (r = 0.80, p < 0.002) and lower yet significant correlations of the pedigree data with both marker types (r = 0.51; r = 0.41, p< 0.002). Information obtained from comparing results of different genetic diversity estimation methods will be particularly important for the improvement and conservation of barley genetic resources. P-72 Identification of Tissue Specific Genes in Triticale C Penniket1,2, D Gaudet1, B Selinger2, and André Laroche1 1Agriculture and Agri-Food Canada, Research Centre, Lethbridge, AB, Canada, T1J 4B1; 2University of Lethbridge, Lethbridge, AB, Canada, T1K 3M4 larochea@agr.gc.ca Triticale is a man made species with favourable agronomic attributes including high yield in both grain and biomass making it a good candidate for production of industrial and energy bio-products. Tissue-specific genes from leaf tissues at 5 developmental stages (from seedling to senescent) and five seed tissues (including the embryo, endosperm, and seed coat tissues) were identified in triticale cv AC Certa, using the Affymetrix wheat GeneChip® array. Over 3% of the 61,127 wheat probesets on the array were found to be expressed in a developmental or tissue-specific manner and over 15% of the probesets were found to be differentially up-regulated in a tissue-specific manner. The numbers of tissue-specific genes ranged from 1 to 193 and 78 to 829 among the leaf and seed tissues respectively. Lists of genes up-regulated in each tissue have been categorized by molecular functions to show global changes throughout development and among tissues. A selection of tissue-specific genes identified using microarray has been evaluated using quantitative real-time PCR to verify the level of tissue specificity. The identified genes will be used to isolate tissue-specific promoters to facilitate the expression of

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novel gene products in triticale and eventually direct transgene expression in triticale. P-73 The effect of light intensity on growth and the production of microcystin congeners in the cyanobacterium Microcystis Susan LeBlanc-Renaud, FR Pick, R Aranda-Rodriguez, and A Saleem Dept of Biology, University of Ottawa, 30 Marie Curie St, Ottawa, ON, Canada, K1N 6N5 slebl027@uottawa.ca Light quality and intensity have been shown to affect the growth of cyanobacteria along with the production of cyanotoxins including microcystins. However, few studies have determined whether light affects the production of specific microcystin congeners. The goal of this study was 1) to determine the effect of light intensity on total microcystin production and the production of different microcystin congeners in Microcystis aeruginosa and 2) to determine if light intensity affects the growth rate of toxic and non-toxic strains differently. Six strains of M. aeruginosa were grown in batch cultures at 25°C under continuous illumination at three levels of light intensity. Growth rate, cell density (by flow cytometry), and production of microcystin congeners variants (by HPLC-MS) were measured for each culture. Among the microcystin producing strains there were significant differences in the number and identity of congeners produced and in the total amount of microcystin produced under different light intensities. This indicates that each strain may represent a distinct chemotype in terms of microcystin production. No significant differences in growth rate were observed between toxin and non-toxin producing strains. P-74 The chloroplastic lipocalin Atchl protects Arabidopsis thaliana against dehydration stress Lévesque-Tremblay Gabriel, Ouellet F, and F Sarhan gabuqam@hotmail.com Lipocalins are small ligand-binding proteins found in bacteria and in invertebrate and vertebrate animals. They have an ability to bind small, generally hydrophobic molecules. Animal lipocalins play an important role in the regulation of developmental processes, and they are involved in the responses of organisms to various stress factors and in signal transduction pathways. Recent reports suggested that lipocalins possess oxidant-scavenging properties. Plants also possess two genuine classes of lipocalins, the temperature-induced lipocalins (TILs) and the chloroplastic lipocalins (CHLs). We recently showed that AtTIL is involved in modulating tolerance to oxidative stress in Arabidopsis thaliana. The current work aims to elucidate the function of the AtCHL protein. Immunoblot analyses performed with an anti-AtCHL antibody showed that the protein accumulates specifically in the lumen of the chloroplast, and to a higher level after dehydration stress or paraquat treatment. AtCHLprom:GUS lines were generated and histochemical staining revealed that the promoter is active in the tips of young leaves, in mature leaves, in the stem nodes and in root vascular tissues. These data prompted us to assay for the possible involvement of hormones in the activity of the promoter.

Only IAA showed a detectable effect, demonstrated by a significant increase in expression in the petiole of mature leaf. For functional characterization, we are performing gain- and loss-of-function analyses on overexpressing (OEX), knock-out (KO), and complementation lines (COMP). The accumulation of the protein upon dehydration stress and paraquat treatment, and the accumulation in the chloroplast lumen are consistent with a possible function of AtCHL in the protection of the photosynthetic machinery during abiotic stress. P-75 Preparation of chlorenchyma protoplasts from single-cell C4 species Bienertia sinuspersici Terry SC Lung and SDX Chuong Dept of Biology, University of Waterloo, ON, Canada, N2L 3G1 schuong@sciborg.uwaterloo.ca Protoplasts serve as a versatile tool in plant genomic, proteomic and metabolomic researches. We have optimized procedures for isolating chlorenchyma protoplasts from Bienertia sinuspersici, the third C4 plant without Kranz anatomy. It features subcellular separation of dimorphic chloroplasts into two cytoplasmic compartments within individual cells, analogous to mesophyll and bundle sheath cells in typical C4 plants, respectively. We showed that complete cell wall removal was obtained after 3-hour incubation with 1% (w/v) cellulose Onozuka R-10 at room temperature, pH 6.0, as indicated by staining with Fluorescent Brightener 28. While the central cytoplasmic compartment in the isolated protoplasts was dispersed using mannitol or sorbitol as osmotica, this compartment was maintained in a medium containing 0.7 M sucrose. The isolated protoplasts remained viable 3 days post-digestion as indicated by fluorescein diacetate staining. These viable protoplasts will be useful for establishing a transformation protocol for this species. Furthermore, proteomic analysis of proteins purified from the two chloroplast populations of the isolated protoplasts will also provide insight into the mechanism of plastidial protein import in the single-cell C4 system. P-76 Isolation and characterization of Cerein 85: a novel bacteriocin produced by Bacillus cereus UW85 Fazli Mabood, A Souleimanov, X Zhou, X He, N Wang, V Muise, and D Smith Plant Science Dept, McGill University/Macdonald Campus, 21,111 Lakeshore Rd, Ste-Anne-de-Bellevue, QC, Canada, H9X 3V9 fazli.mabood@mail.mcgill.ca Bacillus cereus UW85 is a rhizosphere bacterium that has previously been shown to exert biocontrol activity on several plant pathogens. Here we report that this bacterium produces a novel peptide molecule, a bacteriocin, that shows antibacterial activity against closely related strains. The antibacterial compound was isolated and purified using HPLC. SDS-PAGE was conducted to estimate molecular mass of the compounds and was confirmed with Matrix Assisted Laser Desorption Ionization Quadrapole Time of Flight (MALDI-TOF) mass spectrometry. The peptide also showed antibacterial activity in cell free supernatants and was active against several Bacillus species. The bacteriocin showed

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bactericidal activity against Bacillus thuringiensis subsp. thuringiensis and Brevibacillus brevis. This is the first report of Bacillus cereus UW85 producing a bacteriocin; we have named this new compound ‘Cerein 85’. The ability of Cerein 85 to inhibit undesirable bacteria may be of interest as an antimicrobial agent in food and clinical applications. P-77 Molecular characterization of a cytosolic peroxiredoxin in Solanaceae Émilie Maheux1, S Dorion1, G Bélair2, DP Matton1, and J Rivoal1 1IRBV, Université de Montréal, 4101, rue Sherbrooke est, Montréal, QC, H1X 2B2 ; 2Agriculture et Agroalimentaire Canada, 430 Boul Goin, St-Jean-sur-Richelieu, QC, J3B 3E6, Canada maheuxe@cgocable.ca Peroxiredoxins (Prx) are a novel family of redox enzymes involved in the reduction of H2O2 in the different cellular compartments. A full- length Prx (ScPrx1) was cloned from Solanum chacoense, a wild relative of the cultivated potato. Analysis of the predicted primary sequence suggested that the 162 amino acids long protein product is a cytosolic Prx isoform. It was expressed as a (6xHis)-tagged protein in E. coli. The recombinant enzyme was active and could be purified to electrophoretic homogeneity in a single step using a metal affinity chromatography column. The purified protein was characterized using an end-point colorimetric assay. (6xHis)-ScPrx1 reaction was linear with respect to time and amount of enzyme in the assay. The enzyme displayed typical Michaelis-Menten kinetics with respect to its substrate H2O2 and exhibited an unusual lack of sensitivity to pH. (6xHis)ScPrx1 was also shown to be active in the protection of DNA from oxidative damage. Examination of the Arabidopsis genome reveals the existence of several Prx isoforms located in different subcellular compartments. Microarrays studies suggest that cytosolic Prx genes could be involved in plant response to different stress situations. A rabbit polyclonal antibody was raised against recombinant (6-His) ScPrx1. The serum was used to characterize the spatio-temporal expression pattern of cytosolic Prx in Solanum esculentum. Implication of Prx in response to pathogens was also examined. P-78 Alternative Oxidases of Non-Angiosperm Plants Allison E McDonald and JF Staples Dept of Biology, The University of Western Ontario, Biological and Geological Sciences Bldgg, London, ON, Canada, N6A 5B8 amcdon27@uwo.ca Alternative oxidase (AOX) is a respiratory protein present in mitochondrial electron transport chains. Recent work has demonstrated that AOX is more broadly distributed than was previously believed; AOX is found in many eubacteria, protists, fungi, animals, and plants. Most plant AOX research has focused on angiosperms such as Arabidopsis thaliana, tobacco, soybean, rice, and voodoo lily, where a good deal is known about its multigene family, gene expression, and the post-translational control of AOX activity. In contrast, little is known about AOX in other plant groups (e.g. gymnosperms, non-vascular plants). We

examined the taxonomic distribution of AOX in non-angiosperm plants by performing molecular database searches to identify homologous AOX sequences. Using these sequences we designed degenerate primers for use in RT-PCR in order to amplify potentially novel AOX sequences and to assess the expression of AOX mRNA in non-angiosperm plants. Newly identified AOX cDNAs were compared with known angiosperm sequences and used to determine whether a particular N-terminal cysteine residue, which plays a key role in the post-translational regulation of most angiosperm AOXs, is present in non-angiosperm sequences. These findings have direct implications for the evolutionary history of AOX post-translational regulatory mechanisms in plants. P-79 Seasonal phytochemical variation of anti-diabetic principles in lowbush blueberry (Vaccinium angustifolium) Kristina McIntyrea, C Harrisa, P Haddadb, and JT Arnasona aDept of Biology, University of Ottawa, Ottawa, ON K1N 6N5; bDép de pharmacologie, Université de Montréal, Montréal, QC, H3C 3J7, Canada kmcin009@uottawa.ca Seasonal dynamics in the concentration of phenolic compounds and advanced glycation endproduct (AGE) inhibition activity of lowbush blueberry (Vaccinium angustifolium) leaves and stems were assessed over one growing season. Diabetic hyperglycaemia promotes the production of AGEs, which play a significant role in the development of complications associated with type 2 diabetes mellitus. V. angustifolium contains a variety of phenolic compounds, many of which have previously shown anti-diabetic activities. Seasonal changes in the concentration of six compounds in the leaves (chlorogenic acid, rutin, quercetin-3-galactoside, quercetin-3-glucoside, quercetin-3-arabinoside, and quercetin-3-rhamnoside) and twelve compounds in the stems (the six previously mentioned compounds, caffeoyl quinic acid, catechin, epicatechin, and procyanidin B1, B2, and an unknown procyanidin) were assessed using high performance liquid chromatography (HPLC). These trends were examined in relation to seasonal changes in AGE inhibition activity to gain insight into possible active compounds and optimal cultivation time. The concentration of chlorogenic acid, rutin, and quercetin-3-arabinoside changed significantly with sampling date in the leaves and the concentration of chlorogenic acid, catechin, and epicatechin changed significantly in stems. AGE inhibition activity of leaves was significantly greater at the final compared to the initial collection date whereas activity of stems was greatest at the beginning of the season, though not significantly. AGE inhibition activity was greater for stems than leaves, which could be a result of the unique phytochemical composition of stems. Seasonal dynamics varied for individual compounds and variation could be influenced by factors such as herbivory, light and nutrient availability, and genetics. AGE inhibition activity is thought to be influenced by chemical structure and may be related to antioxidant activity. Phytochemical variation between Vaccinium species and growing locations was also assessed using HPLC. Different species contained unique phytochemical markers and relative quantities of some common compounds varied between species. Growing location did affect the quantity of some compounds

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though phytochemical profiles were generally the same for different populations of the same species. P-80 Regulation of stress-Induced proanthocyanidin metabolism in Populus Robin Mellway, LT Tran, MM Towns, and CP Constabel Centre for Forest Biology, Dept of Biology, University of Victoria, PO Box 3020, Station CSC, Victoria, BC, Canada, V8W 3N5 rmellway@uvic.ca The major soluble defence phenylpropanoids produced in poplar leaves are the flavonoid-derived proanthocyanidins (PAs) and the salicin-based phenolic glycosides (PGs). PA biosynthesis in leaves is rapidly induced by insect herbivore damage and other stresses. We are characterizing a family of transcription factors that may play important roles in regulating stress-induced flavonoid metabolism. One of these is transcriptionally upregulated along with PA biosynthetic pathway genes under multiple stress conditions including mechanical wounding, UV-B stress, and infection by a compatible biotrophic fungus. Overexpression of this gene in poplar resulted in trans-criptional activation of the full PA biosynthetic pathway and a significant plant-wide increase in PA concentrations as well as a concomitant reduction in PG concentrations. These changes were found to affect feeding choice and mortality of early instar forest tent caterpillars (FTC, Malacosoma distria), a widespread P. tremuloides herbivore. These findings provide insight into the regulatory mechanisms mediating stress-induced PA biosynthesis and constitute a valuable tool for manipulating phenyl-propanoid metabolism and investigating the biological functions of different carbon-based allelochemicals in poplar. P-81 Regulation of grape CBF gene expression Michelle Moody, M Siddiqua, and A Nassuth Dept of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1 mmoody@uoguelph.ca Many temperate plants can acquire tolerance to freezing temperatures through activation of the CBF pathway. Research on Arabidopsis has shown that cold, light and ABA can be involved in CBF gene activation. We have isolated four CBF genes from Vitis riparia, a wild freezing tolerant grape, and Vitis vinifera, the cultivated wine grape that is sensitive to freezing temperatures (Xiao et al., 2006 and 2008). Based on the recent released grape genome sequence, we have identified at least four additional CBF genes and are in the cloning process. In silico analysis of ~ 1.5 kb “promoter” regions of the 8 Vitis CBF sequences has revealed the presence of several elements that are shared between paralogs and/or orthologs, although the promoter regions of paralogs share less than 15% identity, except for VvCBF6 & 7 which are much more similar. These include two elements, 18 and 21 bp long (“ICEr2B and ICEr2A” respectively), that are somewhat similar to the cold-inducible ICEr2 element in the AtCBF3 promoter, and an as yet unknown 17 bp ICErM element. Promoter::reporter constructs are analyzed by transient expression in agro-infiltrated tobacco leaves to determine

promoter induction by cold and light. The VrCBF4 promoter was found to be cold-inducible and deletion constructs have been prepared to determine which elements are responsible for this. Also constructs with the other Vitis CBF promoters are now being analyzed with the transient expression assay. Similarly, this will determine whether the differences in elements between orthologs from V. riparia and V. vinifera possibly contribute to the difference in freezing tolerance. P-82 Characterization of Arabidopsis thaliana mutants with altered carotenoid profiles Karthikiyan Narayanan1,2, G Katchtourians1, D Hegedus2, and A Hannoufa2 1Dept Food and Bioproduct Sciences, University of Sasktchewan, 51 Campus Dr, Saskatoon, SK, S7N 5A8; 2Agriculture and Agri-Food Canada, 107 Science, Saskatoon, SK, S7N 0X2, Canada kan996@mail.usask.ca ; narayanank@agr.gc.ca Carotenoids belong to the isoptrenoid subfamily, and are widely present in nature. They have both agronomic and economic values as they are exploited for their colors in many crops, ornamental plants, cosmetic and food industries. These biological, agronomic and economic values of carotenoids have created much needed attention to study their biosynthetic pathway and its regulation. The availability of T-DNA tagged Arabidopsis thaliana mutant lines at AAFC-Saskatoon provides an opportunity to uncover the regulatory mechanisms involved in carotenoid biosynthesis. Three screening methods are currently used to screen A. thaliana mutants with altered carotenoid profiles will be reported. The first method involves visual screening based on the seed coat color; the second method relies on seedling phenotypes of pale green leaves with stunted growth. The third method uses norflurazon (an herbicide inhibiting phytoene desaturase enzyme involved in the carotenoid biosynthetic pathway) for screening carotenoid mutants. Three mutants namely; RSC, NFR and SP mutant obtained from each screening method will be discussed. All the three mutants have altered carotenoid profiles, the molecular analyses performed on these mutants revealed a specific link between the regulatory elements that play a role in carotenoid metabolism in plants. P-83 Brachypodium distachyon: A model plant system for studies in Fusarium graminearum pathology C Nasmith and R Subramaniam ECORC, Agriculture and Agri-food Canada, 960 Carling Ave, Ottawa, ON, Canada, K1A 0C6 Giberella zeae (Schw.) Petch (Fusarium graminearum Schwabe) is the causal agent of wheat head blight. Difficulties associated with wheat genetics have compelled researchers to find appropriate plant model systems to study F. graminearum pathology. While Arabidopsis thaliana (L.) Heyn. has proven to be an invaluable tool to study plant-microbe interaction, it is a non-host to F. graminearum, making it difficult to effectively and efficiently study this fungal system. The grass species Brachypodium distachyon (L.) Beauv. has useful study features including a recently sequenced

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genome, reduced ploidy and genome size, as well as a much closer evolutionary relationship to wheat and other cereal crop species than A. thaliana. This has created great interest in B. distachyon as an alternative plant model system for plant-microbe studies. Previously untested for Fusarium infection, we have performed assays on B. distachyon resulting in the first documented accumulation of 15-ADON. Subsequent assays were performed that allowed separation of F. graminearum strains based on visible infection symptoms over time as well as by trypan blue staining. Further research will no doubt confirm that B. distachyon will be an indispensable tool required for Fusarium graminearum pathology studies. P-84 Towards identifying targets of farnesylation involved in abscisic acid signaling and drought tolerance. Julian Northey, F Delmas, and P McCourt Dept of Cell & Systems Biology, Earth Science Centre, 25 Willcocks St, Toronto, ON, Canada, M5S 3B2 julian.northey@utoronto.ca A number of years ago era1 was discovered, which modulates ABA signaling through negative regulation (Cutler, Ghassemian et al. 1996). ERA1 encodes the β-subunit of a farnesyltransferase (FTase) and mutant plants are deficient in protein farnesylation. era1 was initially identified by screening for the inability to germinate on low concentrations of exogenous abscisic acid (ABA) and was later found to show a hypersensitive ABA response at the level of stomatal closure, thereby conferring drought tolerance (Pei, Ghassemian et al. 1998). Further analysis of era1 mutants revealed additional pleiotropy. For example, meristem and flower development are altered as well the process of meiosis. To date, relatively few proteins have been shown to be farnesylated in plants. These include the first plant protein shown to be farnesylated, the molecular chaperone ANJ1 from Atriplex nummularia, as well as ATFP3, Apetala1, ROP10, AtNAP1 and AtRAC7 from Arabidopsis. Unfortunately, the identification of these targets has not given much insight into how farnesylation regulates plant development and signaling. For example, there is still no clear understanding of how loss of farnesylation can confer ABA hypersensitivity. As previously mentioned, the simplest interpretation is that farnesylation acts as a negative regulator of ABA signal transduction. However, with the lack of a molecular target this interpretation remains to be proven. In an effort to identify the molecular target/s of farnesylation in Arabidopsis, a high-throughput genetic approach has been conducted. Of the 582 putative farnesylation targets in Arabidopsis, 290 homozygous T-DNA knockout lines representing 217 unique genes have been screened for ABA hypersensitivity at the level of germination as well as drought tolerance. Current results will be presented. P-85 Evaluation of a Cree botanical for its role to potentiate cytotoxicity and alter gene expression C Ogrodowczyk1,2, C McDonald2, J Popesku1, H Xiong1, A Muhammad2, B Walshe-Roussel1,2, J Coonishish3, BC Foster2,4, and JT Arnason1,2

1OCIB, and 2Centre for Research in Biopharmaceuticals and Biotechnology, University of Ottawa, ON; 3Cree Nation

of Misstissini, QC; 4Office of Science, Therapeutic Products Directorate, Health Canada, Ottawa, ON carolina07@gmail.com A Cree botanical, AD09, used by the Cree of Eeyou Istchee to treat type II diabetes (T2D), was evaluated for its role to potentiate cytotoxicity in human Caco-2 intestinal cells and in modulating gene expression. To this end, Caco-2 cells were exposed to various concentrations of ethanolic and water extracts for a period of 24 hours. Cytotoxicity levels were then measured through Promega’s CytoTox 96® Non-Radioactive Cytotoxicity Assay. Two isolated compounds, goodyeroside and quercetin-3-O-glucoside were also tested. Furthermore, Caco-2 cells were exposed to AD09 at a concentration of 100 �g/mL and microarray experiments were performed using human 19K cDNA arrays to establish gene transcript changes. The extracts and compounds isolated from AD09 do not show significant toxicity, thus we can speculate that these extracts will not pose an immediate toxicity danger, especially when it comes to first-pass metabolism, for which the Caco-2 cells are commonly used to study. However, any possible gene transcript changes, particularly to the cytochrome P450 metabolic enzymes, that may occur can lead to possible flags for drug interaction, since many drugs are metabolized by these enzymes and T2D patients usually take many concurrent medicines along with the plant. Microarray experiments revealed no changes to the cytochrome P450 family of genes, however, Bayesian analysis of the microarray yielded 304 downregulated mRNAs (p<0.05) with a fold-change greater than 1.5 with significant downregulation of key transcription factors and members of different signaling pathways suggesting an overall downregulation of the whole gene transcription system. Further studies are warranted to examine these interactions. P-86 In vivo multi-site phosphorylation of bacterial-type PEP carboxylase from developing castor oil seeds Brendan O’Leary and WC Plaxton Dept of Biology, Queen’s University, Kingston, ON, Canada, K7L 3N6 2bo@queensu.ca All sequenced plant genomes contain several conserved genes encoding ~107-kDa plant-type PEP carboxylase (PTPC) polypeptides (p107). Each genome also contains an enigmatic bacterial-type PEPC (BTPC) gene encoding an ~118-kDa polypeptide (p118) that exhibits low sequence identity with PTPCs. The novel ~910-kDa Class-2 PEPC hetero-octameric complex from developing castor oil seeds (COS) arises from a tight interaction between p107 PTPC and p118 BTPC subunits. Multi-site p118 phosphorylation was revealed by Pro-Q Diamond staining and phosphate-affinity PAGE of p118-enriched COS co-IP eluates. Tandem MS/MS established pThr5 and pSer425 as p118 phospho-sites. As pSer425 is adjacent to Pro426, Ser425 is subject to Pro-directed phosphorylation, a major regulatory event in many cellular processes. pSer425 was confirmed by p118 immunoblotting using anti-(phosphosite specific)-IgG. This and an analogous IgG being raised against the pThr5 site are being used to assess the influence of COS development and photosynthate supply on p118 phosphorylation. The phospho-status of Ser425 appeared unchanged throughout COS development or

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following sucrose starvation caused by COS depodding. Thus, signaling pathways responsible for photosynthate-dependent COS p107 phosphorylation differ from those controlling in vivo Ser425 phosphorylation of p118. Ser425 (de)phosphorylation did not influence p118's tight interaction with p107 in the high Mr Class-2 PEPC complex, nor p118's extreme susceptibility to limited in vitro proteolysis by an endogenous thiol protease. A third phospho-site was suggested by p118's cross-reaction with anti-(pSer/pThr Akt)-IgG; Ser879 is a promising candidate as it is within both an Akt recognition motif, as well as a conserved motif for SNF1-related protein kinases. Key areas for our ongoing research include establishing the: (i) biological function(s) of Thr5 and Ser425 phosphorylation in COS BTPC, as well as additional p118 phospho-site(s), (ii) PEPC kinase/protein phosphatase system(s) that control multi-site p118 phosphorylation in vivo, & (iii) structural basis for the tight interaction between COS p118 and p107. P-87 The plasma membrane lipocalin AtTIL protects Arabidopsis thaliana against oxidative stress Ouellet François, Frenette Charron J-B, Houde M, and F Sarhan ouellet.francois@uqam.ca Plant lipocalins accumulate in response to environmental stresses such as cold stress, however their cellular functions are still unknown. Here we demonstrate that the Arabidopsis AtTIL lipocalin is involved in modulating tolerance to oxidative stress. AtTIL knock-out plants are very sensitive to sudden drops in temperature and paraquat treatment, and dark-grown plants die shortly after transfer to light. Complementation restores the normal phenotype and overexpression enhances tolerance to the oxidative stress caused by freezing, paraquat and light. Moreover, the accumulation of AtTIL delays flowering and senescence. Microarray analyses identified several differentially-regulated genes encoding components of oxidative stress and energy balance. These findings are in agreement with the recent findings that animal lipocalins are involved in tolerance to oxidative stress and modulation of life span. Lipocalins thus share a conserved function in development and stress responses among species. P-88 The effect of natural products on human health and wellness Humayoun Akhtar1*, BC Foster2,4 JT Arnason2, A Krantis2, T Xing3, M Bryan1, M Smith2,3, S Nguyen2, and H Huang2 1Guelph Food Research Centre, Agriculture and Agri-Food Canada, 93-Stone Rd W, Guelph, ON, N1G 5C9; and 2

Centre for Research in Biopharmaceutics and Biotechnology, University of Ottawa, Ottawa, ON; 3Ottawa-Carleton University Biology Institute, Ottawa, ON; and 4Therapeutic Products Directorate, Health Canada, Tunney’s Pasture, Ottawa, ON AkhtarH@AGR.GC.ca The demand for natural health products (NHPs) have increased in recent years as consumers are seeking ways to control their own health through diet. This study examines the health benefits and possible drug

interactions of some Canadian grown and foreign NHPs commonly consumed by patients living with Crohn’s and colitis. CYP inhibition assays were used to determine potential drug interactions of selected NHPs. All 48 crude extracts were prepared in 80% methanol (MeOH) at concentrations of 50 mg/ml and were tested against ketoconazole as a positive control. Data obtained showed that extracts of certain soybeans, basil, celery seeds, cumin, oregano and rosemary inhibited CYP3A5 at levels between 80-100%. Extracts of a larger group of soybeans, as well as cowpeas, black beans, dill weed and fennel seeds displayed more moderate levels of inhibition ranging from 30-65%. Kirby-Bauer disc diffusion assays were used to test the antimicrobial properties. Methanolic extracts of the collected samples were tested against Acenobacter calcoaceticus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Listeria innocua, Providencia stuartii and Pseudomonas putida incubated aerobically at 37°C. Oregano leaves and rosemary are the most active and tested positive against all bacterial species. Celery, fennel seeds, cumin, and dill weed are also relatively active. Preliminary testing of boiled samples showed a small decrease of activity in some samples. The current results of this study, however, shows that certain foods do possess antimicrobial properties and may be beneficial to patients. Future studies will examine the antimicrobial effects in anaerobic conditions as well as the estrogenic and immunological effects of the samples. CYP inhibition assays will be conducted using CYP19, 3A7, 2C9, 2C19 and 2D6. Results from this study may serve as a dietary guideline for patients with Crohn’s and colitis as well as those taking prescription drugs. P-89 Why does nitrate induce AOX in Chlamydomonas reinhardtii? Pakkiriswsami S and Maxwell DP B&GS, Dept of Biology, UWO, London, ON, Canada, N6A5B7 spakkiri@uwo.ca In the green alga Chlamydomonas reinhardtii a shift in nitrogen source from ammonium to nitrate results in a rapid induction of the alternative oxidase (AOX) and associated alternative pathway respiratory capacity. It has been hypothesized that this induction is triggered by changes in photosynthetic metabolism owing to the increased demand of nitrate assimilation, as compared to ammonium assimilation, for cellular reductant.Besides increasing generation of NADPH, an up regulation of photosynthesis in the chloroplast would lead to increases in cellular ATP. In response to increased chloroplast ATP generation induction of AOX and alternative pathway capacity would decrease the mitochondrial production of this metabolite while still maintaining high levels of tricarboxylic acid cycle activity. The current study investigated the influence of photosynthesis on the nitrate-dependent induction of AOX by using C. reinhardtii grown in a medium that demands photoautotrophic growth. Based upon light response curves for oxygen evolution, a shift from ammonium to nitrate-containing media resulted in a significant increase in both apparent quantum yield of oxygen evolution and photosynthetic capacity. Changes in chlorophyll a fluorescence were also observed over a 12 hour nitrate shift which is indicative of increased energy utilization which includes a decrease in excitation pressure and a decrease in non-photochemical quenching of

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fluorescence. The large induction of AOX protein accumulation in response to the nitrate shift was mirrored by an increase in alternative pathway capacity, but no significant change in overall respiration. To investigate whether the rate of photosynthesis influenced the nitrate-dependent induction of AOX, its accumulation was monitored in cells grown under high, moderate and low irradiances. While cellular ATP concentration was found to be positively correlated with growth irradiance, no change in AOX accumulation was found. The kinetics and extent of AOX accumulation were similar in cells grown at 20 µmol m-2 s-1 as cells grown at 1400 µmol m-2 s-1. These data do not support the hypothesis that an increase in AOX within the mitochondrion is tied to changes of photosynthesis occurring within the chloroplast. P-90 Characterization of cystathionine γ-synthase from chickpea, field pea and lentil Jennifer E Pearce and SM Aitken Dept of Biology, Carleton University, 1125 Colonel By Dr, Ottawa, ON, Canada, K1S 5B6 susan_aitken@carleton.ca Pulse crops (e.g. chickpeas, field peas, and lentils) are a major staple food for both humans and non-ruminant animals; however, they contain nutritionally insufficient levels of the required amino acid methionine. Previous attempts to raise methionine levels in plants have included the increased expression of genes of the methionine biosynthetic pathway and anti-sense constructs of genes from competing pathways. This work has demonstrated the regulatory complexity of methionine biosynthesis. In plants, cystathionine-γ-synthase (CGS) catalyzes the committing step in the transsulfuration pathway, which converts cysteine to homocysteine, the immediate precursor of methionine. The genes encoding CGS from chickpea, field pea and lentil have been sequenced and share 83-86% and 71-74% amino acid identity with CGS from Glycine max and Arabidopsis thaliana, respectively. The amino acid sequence of CGS from these three pulse crops includes the N-terminal plastid targeting and regulatory regions observed in CGS from other plant species, but which are not observed in the corresponding bacterial proteins. Comparison with CGS from tobacco, for which a crystal structure is available, demonstrates conservation of the key active-site residues in the catalytic domain. Complementation of an E. coli �metB strain, lacking the gene encoding CGS, by the chickpea, field pea and lentil CGS cDNAs has confirmed their function. P-91 Common bacterial blight in Phaseolus vulgaris: The hunt for resistance genes Perry GE, Pauls KP, Reinprecht Y and J Chan University of Guelph, Dept of Plant Agriculture, ON, Canada perryg@uoguelph.ca Common bacterial blight (CBB) is a significant pathogen in dry bean (Phaseolus vulgaris) crops throughout the world, which results in reduced yield and seed quality. This disease presents itself as brown lesion of seeds, leaves and pods and is caused by Xanthomonas axonopodis pv. phaseoli. Recently, a CBB-resistant cultivar, OAC-Rex was developed from a cross between P. vulgaris and a CBB-resistant accession of Phaseolus acutifolius. Another CBB-

resistant line, HR67, was produced from a separate cross between P. vulgaris and P. acutifolius. OAC-Rex represents the first CBB resistant cultivar released in North America, however the genes responsible for this resistance not yet been identified. Binary-bacterial artificial chromosome (BiBAC) libraries were created using the BiBAC2 vector, to aid in the identification of the CBB-resistance genes in OAC-Rex and HR67. The libraries were screened with CBB resistance-associated molecular markers identified by previous studies, and the identified clones were analyzed using a gel-based restriction fingerprinting method for assembly into contigs. The clones at the extreme ends of the contigs will be end-sequenced and this data used to re-probe the libraries and expand the coverage of the contig. The unique clones will be transiently expressed in susceptible bean lines using Agrobacterium tumafaciens, and the plants will be infected with X. axonopodis. Clones containing genes for CBB resistance should cause a significantly reduced the X. axonopodis-induced lesion. P-92 Genomics of poplar (Populus trichocarpa x deltoides) systemic defense response to insect herbivory by forest tent caterpillar (FTC, Malaco-soma disstria) reveals novel changes in sink leaves Ryan N Philippe, S Ralph, S Jancsik, R White, S Mansfield, and J Bohlmann UBC Michael Smith Labs, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4 rphilipp@msl.ubc.ca The availability of a poplar (Populus trichocarpa) genome sequence is enabling new research approaches in angiosperm tree biology. Much of the recent genomics research in poplars has been on wood formation, growth and development, resistance to abiotic stress and pathogens. In this study, recently developed genomics resources were used for large-scale profiling of defense responses of poplar trees to insect herbivory. Using cDNA microarrays, we profiled spatial and temporal transcrip-tome responses in both source and sink leaves in response to FTC regurgitant. Large-scale transcriptome profiling indicated that induced responses in treated source leaves were rapid (by 6hrs) and involved varied physiological processes from both primary and secondary metabolism. Untreated systemic source leaves also developed a similar transcriptome profile by 24hrs, though induction was slower than in treated source leaves. However, transcriptome response in untreated juvenile systemic sink leaves at the crown of poplar saplings was very different when com-pared to source leaves, involving a cascade through time of expression profiles found only in sink leaves. Strong up-regulation was observed by 2hrs at ~1.5 m from damage sites, mainly of genes involved in primary metabolism, transport, and general stress response. Isoprene synthase expression increases in systemic leaves while decreasing in treated leaves. Galactinol synthase FL-cDNAs, involved in production of raffinose, have been cloned and are shown to be induced by damage with source- and sink-specific patterns of expression. Galactinol and raffinose metabolite levels also increase systemically in response to herbivory. A defense profile involving response in secondary meta-bolism and resistance genes involved in poplar defense is observed by 24hrs in sink leaves. Overall, a model of poplar defense responses to insect herbivory begins to emerge, whereby a cascade of changes in the transcriptome of

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treated and untreated leaves leads to the rearrangement of primary metabolism and the induction of resistance genes for successful systemic defense. P-93 Molecular and physiological characterization of heat stress in the Antarctic psychrophile/ Chlamydomonas raudensis Marc Possmayer, DP Maxwell, and NPA Hüner University of Western Ontario, Dept of Biology and The Biotron mpossma@uwo.ca, dmaxwell@uwo.ca, nhuner@uwo.ca The green alga Chlamydomonas raudensis Ettl (UWO 241) is psychrophilic, having an optimum growth temperature between 5 and 10ºC and an inability to grow above 20ºC. The characterization of this alga’s response to non-permissive growth temperature should provide insights into the underlying basis of its psychrophily. UWO 241 cultures shifted from permissive to non-permissive growth temperature (24ºC) exhibited Fv/Fm values, the maximum quantum yield of PSII, which declined only slightly after 12h exposure to non-permissive growth temperature and recovered to near pre-stress values 18h after being returned to the permissive growth temperature. qP, the fraction of absorbed photons used for photochemistry, followed a similar pattern. Despite the stability of photosynthetic parameters during heat stress, LHCII transcript abundance dropped dramatically during 12h of exposure to non-permissive growth temperature. The differential display technique was used to monitor more global changes in transcript abundance in the first six hours of exposure to non-permissive temperatures. Most transcripts remained at a constant relative abundance during this period, while a smaller number increased or decreased in abundance over the course of the stress. Transcripts which increased in abundance were cloned and sequenced, however none of the clones were similar to known genes. Further physiological and molecular biological assays will provide insight into the disruption of UWO 241’s cellular processes which occur at a temperature which is eventually lethal to this organism. P-94 Characterization of nucleolar localization of Arabidopsis ribosomal protein gene family L23a Raghavendra Prasad Savada and PC Bonham-Smith Dept of Biology, University of Saskatchewan, Saskatoon, SK, Canada prasadaralasurali@gmail.com Ribosomes are macromolecular enzymatic complexes composed of ribosomal RNAs and ribosomal proteins (r-proteins), organized into a large subunit and a small subunit. They are responsible for protein synthesis in all living organisms. The ribosome is a ribozyme with rRNA constituting the peptidyl transferase active center of the large subunit and r-proteins performing essential functions such as the maintenance of ribosome structure and transport of the nascent polypeptide. Subsequent to their synthesis in the cytoplasm, the majority of r-proteins are transported through the nucleus to the nucleolus, the site of ribosome subunit biogenesis. RPL23a, a member of the conserved L23/L25 family of primary rRNA binding proteins, is one of 81 Arabidopsis (Arabidopsis thaliana) r-protein

gene families consisting of two members; RPL23aA and RPL23aB. To date, nuclear localization, the first step in nucleolar localization, of these proteins has not been characterized. Both of these proteins have a putative bipartite nuclear localization signal (NLS) - KKADPKAKALK. In the present work, we are investigating the need for this putative NLS to drive nuclear localization of RPL23aA/B. Results to date suggest that mutating either the first half (KKAD) of the NLS to TTDA, KKAA, KAAD, AAAD, AKAA or KAAA or the second half (KALK) to AALK, KALA or TDGT has no effect on nuclear localization of RPL23aA. Further results of NLS-deletions and nucleolar localization signal mutations will also be presented. P-95 IRX9, a gene involved in xylem development in Arabidopsis thaliana Wensheng Qin1, 2 and C Somerville1, 3

1Dept of Plant Biology, The Carnegie Institution, Stanford, CA 94305, USA; 2Current: Biorefining Research Initiative and Biology, Lakehead University, Thunder Bay, ON, Canada, P7B 5E1; 3Current: Energy Biosciences Institute, University of California at Berkeley, CA 94720, USA wqin@Lakeheadu.ca In Arabidopsis thaliana, the IRREGULAR XYLEM (IRX) genes are required for proper xylem development. Loss of function of IRX9, a glycosyltransferase, causes a collapsed xylem phenotype and decreases xylose and cellulose in the cell walls. This results in a mutant plant which is much smaller than wild type plant. IRX9 is specifically expressed in the cells undergoing secondary wall thickening and targets to the Golgi, where glucuronoxylan is synthesized. In order to study how this gene is involved in xylem development and how it coordinates with other related genes, we transformed irx9 plants with HA/StrepII tagged IRX9 under the 35S and native promoters. Overexpression of IRX9 did not rescue the phenotype, however expression of IRX9 under the native promoter rescued the mutant phenotype. Tagged IRX9 protein was isolated from rescued plants and detected by Western blot using anti-HA antibody. We isolated protein complexes associated with IRX9. Interacting proteins of IRX9 are being identified and biochemical characteristics are being determined. P-96 Heterologous expression and characterization of recombinant bacterial-type phosphoenolpyruvate carboxylase from developing castor oilseeds Srinath K Rao, B O'Leary, and WC Plaxton Dept of Biology, Queen’s University, Kingston, ON, Canada, K7L 3N6 raosrin@queensu.ca The triglyceride-rich endosperm of developing castor oil seeds (COS) contains two classes of phosphoenolpyruvate carboxylase (PEPC). Class-1 PEPC is a typical 410-kDa homotetramer of 107-kDa (p107) plant-type PEPC subunits, whereas the novel Class-2 PEPC ~910-kDa hetero-octameric complex arises from a tight interaction between Class-1 PEPC/p107 and enigmatic bacterial-type PEPC (BTPC) 118-kDa polypeptides (p118). Distinctive develop-mental profiles and kinetic properties led to the hypotheses that: (i) Class-1 and Class-2 PEPC respectively support PEP flux required for storage protein versus oil synthesis, and (ii)

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p118 functions as a regulatory subunit that desensitizes Class-2 PEPC to allosteric effectors. In vivo p107 and p118 phosphorylation occurs and may contribute to the control of COS photosynthate partitioning. Employing a pET28b vector, the entire coding sequence of COS BTPC was introduced into E. coli BL21 codon plus (RIL) as an N-terminal His-tagged fusion protein. BTPC was expressed as a soluble active PEPC and purified to homogeneity using Ni2+-affinity chromatography and Superdex 200 gel filtration FPLC. Results indicate that the recombinant BTPC irreversibly aggregates into a high mol. wt. complex that loses activity during purification. Initial binding studies were carried out by mixing recombinant BTPC with homo-geneous native Class-1 PEPC from developing COS. Non-denaturing PAGE demonstrated that the recombinant BTPC readily associates with the Class-1 PEPC homotetramer in vitro to form the 910 kDa Class-2 PEPC complex. Further kinetic, structural, and immunological studies of the recombinant COS BTPC and in vitro reconstituted Class-2 PEPC are in progress. P-97 Development of novel antibodies raised against conserved peptide sequences for the analysis of carbon metabolism in Spartina alterniflora Jolene Read, A Cockshutt, and RJ Ireland Mount Allison University, Dept of Biology, 63B York St, Sacvkille, NB, Canada, E4L 1G7 mbssll@mta.ca Spartina alterniflora is a successful C4 plant that colonizes the intertidal region of the Atlantic coast, with a 5-month growth season from May to September. S. alterniflora has been classified as a full C4 plant at the beginning of the growth season, with a transition to a C3-C4 intermediate later in the season. Spartina has been classified as a PEPCK-type C4 plant through metabolite pool analysis and enzyme kinetics, however, previous work has not differentiated between the decarboxylating role of PEPCK in C4 metabolism and the gluconeogenic role of PEPCK. In order to study the role of PEPCK, a novel antibody raised against a PEPCK-specific peptide was designed and produced. This antibody was used to quantify relative PEPCK protein abundance over a growth season in S. alterniflora leaves using immunoblotting. The large subunit of RuBisCO (RbcL) and cytosolic fructose-1,6-bisphosphatase (cFBPase) were quantified in parallel to PEPCK. From early May to mid-July, PEPCK expression was found to parallel RbcL expression, with a peak in relative protein abundance in early June. RbcL then declined for the rest of season. From mid-July to September, PEPCK expression paralleled cFBPase, both proteins showing a secondary peak in mid-August, around the time of flowering and the onset of leaf senescence. These patterns imply that PEPCK is involved in C4 metabolism at the beginning of the season when S. alterniflora is a full C4 plant, however as it transitions to a C3-C4 intermediate, there is less need for the decarboxylating role. With the start of leaf senescence, PEPCK plays an active role in gluconeogenesis to form transport sugars from the breakdown of leaf proteins and lipids.

P-98 Identification of the genes coding for fibre traits in soybean [Glycine max L. (Merr)] stem Yarmilla Reinprecht and KP Pauls Dept of Plant Agriculture, University of Guelph, Guelph, ON, Canada, N1G 2W1 yreinpre@uoguelph.ca The Ontario automotive industry represents an attractive new market for agricultural products. The increased use of plant fibres in automotive parts is limited by the functional performance of the fibre composites compared to existing glass and polypropylene composites. Natural fibre is composed of cellulose monofilaments cross-linked with lignin and hemicellulose. The non-cellulose components of plant fibre not only do not contribute value to the end product, but they actually detract value as their structure degrades at lower temperatures than cellulose. An early priority will be to reduce the amount of the non-cellulose contributors from the cellulose fibre value stream as cost-effectively as possible. The objective of this research was to identify genes and map Quantitative Trait Loci (QTL) for fibre traits in soybean stem that are related to the performance of the fibres in composite materials used for industrial purposes. Based on available information for genes/sequences associated with the cellulose, hemicellulose, pectin and lignin biosynthesis as well as cell wall proteins and modifying enzymes in soybean (and other plant species) sequence-specific PCR primers were designed and screened with the parental DNA for a recombinant inbred population that differs for stem properties. Screening of the recombinant inbred (RI) population and subsequent mapping is underway. The identified fibre genes will be converted to markers that can easily be scored to allow rapid introgression into elite germplasm and creation of agriculturally acceptable varieties in which the cellulose is more easily extractable as pure filaments, and hence have higher levels of crystallinity. This will lead to lower costs of fibre extraction from soybean residue, coupled with higher levels of resistance to thermal degradation and increased utility in materials manufacture. P-99 Characterization of corn cellulose fiber for manufacturing automotive plastic parts Riaz M, Pauls KP, Erikcson L, and Raizada MN University of Guelph, Dept of Plant Agriculture, ON, Canada mriaz@uoguelph.ca Every car on the road contains more than 150 kg of plastic produced mainly from petroleum. The use of plant fibers for reinforcement could reduce the amount of glass fiber used and hence reduce the weight of the material. Also, the addition of a natural fiber to a plant based plastic might make it biodegradable or re-useable. Agriculture and specifically corn production in Ontario provides a large source of natural fiber that might be used in the automobiles as replacements for glass fibers in plant-based or petroleum-based plastics. Corn stalk fibers have good specific strengths, low cost, low density and good biodegradability. However, the use of corn fiber reinforced polymeric composites in automotive parts is limited due to a lack of information about their functional performance properties, especially after exposure to repeated cycles of freezing and thawing. Corn varieties differ in the

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compositions of their cell walls, which affects the functional properties of biomaterials produced from them. The current project is aimed to study the relationships between the genetic makeup of corn varieties and their fiber compositions and functional properties. Quantitative trait loci (QTLs) for acid detergent fiber, neutral detergent fiber, acid detergent lignin along with QTLs for corn stalk fiber composition (especially ferulic acid content) will be determined in a recombinant inbred population that is segregating for ferulic acid content. The study will provide a genetic understanding for the improvement of the cell wall components for bioproduct use. This could lead to the creation of agriculturally acceptable varieties of corn in which the cellulose is more easily extractable as pure filaments, and hence contain higher levels of crystallinity. It will reduce costs of fiber extraction and hence increase its application value. The current research will ensure a stable supply of renewable corn cellulose fiber that will be very valuable to the automotive industry in the future. P-100 Alteration of hexokinase activity levels in transgenic potato (Solanum tuberosum) roots affects their growth and glucose phosphorylation Claeyssen E, Dorion, S, Clendenning, A, Moisan M-C, Auslender E, and Jean Rivoal IRBV, Université de Montréal, 4101 rue Sherbrooke est, Montréal, QC, Canada, H1X 2B2 jean.rivoal@umontreal.ca We have examined the effects of altering hexokinase (HK, EC 2.7.1.1) activity of plant roots on their growth and carbon metabolism. Potato (Solanum tuberosum) roots were transformed with a Solanum chacoense HK cDNA in sense and antisense orientations to constitutively over- and underexpress HK, respectively. Twenty-three root clones were generated that exhibited more than an 11-fold variation in HK activity levels (between 72% and 800% of those in control clones transformed with an empty vector). Protein separation by anion-exchange chromatography revealed at least two HK isoforms in the potato roots, which activities were differently affected by sense and antisense strategies. A survey of 18 enzymes of primary metabolism showed that only HK activity was modified significantly in the transgenics. Elevated HK activity levels resulted in reduced growth rates, thus showing for the first time that root HK exerts major control on growth of this heterotrophic organ. We observed a trend towards a proportionate decrease in glucose and fructose contents with increasing HK activities in the transgenic population, an indication that both sugars may serve as substrates for the HK reaction. Levels of malate, Arg, Phe, Thr and γ-aminobutyric acid were also altered in transgenic roots, which may best be explained in terms of interference of HK manipulation with several biosynthetic pathways. The flux control coefficient of HK over glycolysis at the step of glucose phosphorylation was measured for the first time in plants, and was particularly high (0.76). The high flux control coefficient of HK and the metabolic perturbations occurring in the transgenic roots are discussed in relation to the effects of altered HK activity on their growth rates. (Supported by NSERC)

P-101 Leaf vein patterning: a new approach to bridge the gap between molecular and theoretical studies Anne-Gaëlle Rolland-Lagan University of Ottawa, Dept of Biology, 30 Marie Curie Pvt, Ottawa, ON, Canada K1N 6N5 arolland@uottawa.ca Plant vasculature plays a major role in transporting water, minerals and nutrients, and also provides mechanical support. In most angiosperms, leaf veins form a network which arises progressively as the leaf grows. To investigate how vein patterns form, two main approaches have been used in recent years: the experimental approach involves identifying the genes involved and visualizing in detail early molecular markers of vein patterning. On the other hand, theoretical models have been proposed, which try to how vein networks can arise from a tissue of non-differentiated cells. The lack of quantitative data on vascular patterns during leaf ontogeny makes it difficult to test these models. In an attempt to provide a bridge between experimental data and theoretical studies, we developed algorithms for analyzing vein pattern formation quantitatively in space and time during leaf development, and analyzed vascular patterning in the first rosette leaf of wild type Arabidopsis thaliana. This revealed pattern heterogeneities in time and space, which we propose may be related to both the distribution of auxin and the growth pattern of the leaf. Quantitative analyses provide a way to compare leaf vein patterning parameters in different species, different genotypes, and plants grown under different conditions. This should lead to new hypotheses on patterning mechanisms to incorporate in molecular and theoretical modeling studies. Quantitative data may also be extracted from simulation models, in order to compare experimental and theoretical data and test model validity. Quantitative analyses at the tissue level therefore provide a two-way link between theoretical work and experimental work to further explore patterning mechanisms during development. P-102 The Lack of IMMUTANS is Necessary But Not Sufficient to Account for the Variegated Phenotype of the immutans Mutant of Arabidopsis thaliana Dominic Rosso1, D Saccon1, W Li1, S Wang1, LA Schillaci1, SR Rodermel2, DP Maxwell1, NPA Hüner1 1Dept. of Biology and The Biotron, University of Western Ontario, London, Canada; 2Dept. of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa nhuner@uwo.ca The variegated phenotype of the immutans mutant of Arabidopsis thaliana can be completely suppressed by growth under low light such that it is indistinguishable from the wild type (Rosso et al. 2006 Plant Physiol 142:574-585). We hypothesized that excitation pressure regulates the extent of variegation in immutans. To test this hypothesis, we developed a nondestructive imaging technique from which we quantified the extent of variegation in vivo as a function of developmental time. Immutans was grown at either 25ºC or 12ºC with increasing irradiance (50, 150 and 450 µmol photons m-2s-1) and short day (8h) photoperiod. As growth irradiance increased at 25ºC, the extent of variegation increased from no detectable variegation at 50 µmol photons m-2s-1 to a maximum of 65% variegation at

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450 µmol photons m-2s-1. Furthermore, mid-log phase immutans seedlings grown at 12ºC exhibited greater variegation than mid-log phase immutans seedlings grown at 25ºC at all light levels tested. The extent of variegation was positively correlated with an increase in excitation pressure created either by exposure to low temperature or by exposure to increased irradiance. An examination of chloroplast biogenesis during the light-dependent con-version of etioplasts to chloroplasts in WT and immutans indicated, that although the disassembly of prolamellar bodies occurred normally, structural and functional analyses indicated that the subsequent assembly of thylakoid membranes was inhibited under high excitation pressure in immutans compared to WT. Although IMMUTANS is not involved in photoprotection in mature, fully expanded leaves, it lowers excitation pressure specifically during the early stages of chloroplast biogenesis and thylakoid membrane assembly. However, photoprotection by IMMUTANS appears to be a consequence of constitutive rather than inducible IMMUTANS expression. In contrast to IMMUTANS, its mitochondrial analog, AOX1a, was differentially expressed in immutans in response to excitation pressure compared to WT. We conclude that the lack of IMMUTANS is necessary but not sufficient to account for the variegated phenotype of immutans. Rather, it is the excitation pressure to which cells are exposed early in chloroplast development that determines the sectoring patterns associated with the variegated phenotype associated with immutans. P-103 Optical and electron microscopical imaging of single plant cells - Acceleration of sample processing using microwaves Monisha Sanyal, Y Chebli, F Bou Daher, L Aouar, and A Geitmann IRBV, Dép de sciences biologiques, Université de Montréal, 4101 rue Sherbrooke est, Montréal, QC, Canada, H1X 2B2 anja.geitmann@umontreal.ca The discovery and development of highly sophisticated microscopes has made possible the 3D visualization of ultra-structural details within a cell at an atomic level. Although live cell imaging is becoming increasingly popular, numerous applications still rely on tissue fixation and processing which are time consuming processes. Therefore, efforts minimization of fixation and tissue processing times is important to reduce or prevent structural impact on the tissue. Microwave (MW) ovens were first introduced to accelerate sample processing in the 70’s. In the present study we aimed at the optimization of MW technology for the processing of single plant cells for both optical and electron microscopy. Due to the presence of cell wall and vacuole, plant cells generally require rather prolonged incubation times with fixation and dehydration solutions and thus would profit greatly from an accelerated protocol. Our model system is the pollen tube, commonly used for the study of anisotropic growth and also to understand the structural dynamics and material properties of cells exhibiting polarized growth. Due to their extremely rapid growth and active intracellular transport processes, high quality fixation of pollen tubes is critical for the preservation of cellular ultrastructure and polarity. We tried to optimize the two important variables: MW wattage and exposure time. We tested several staining and

immunohistochemistry procedures to assess the efficiency and quality of MW-assisted fixation protocols on pollen tubes. Labeling of cell wall components with flurochromes and monoclonal antibodies revealed typical label known from conventional fixation procedures. The spatial configuration of the actin cytoskeleton in pollen tubes is notoriously difficult to preserve during fixation, but in our protocols using rhodamine-phalloidin it was clearly labeled. In all these protocols there was clear gain of experimentation time, with no compromise to structural integrity as was evident when comparing with the bench top processing. The same was true for the vacuum assisted-MW processing of samples for transmission and scanning electron microscopy. In summary, we were able to optimize an accelerated MW-assisted processing for single plant cells that provided high quality structural preservation of cells useful for microscopical imaging applications. P-104 Mechanisms and regulation of thermal energy dissipation in seedlings of Lodgepole pine undergoing cold acclimation Leonid V Savitch3, AG Ivanov1, M Krol1, G Öquist2, and NPA Huner1 1Dept of Biology, The University of Western Ontario, London, ON, Canada, N6A 5B7; 2Umeå Plant Science Center, Dept of Plant Physiology, Umeå University, S-901 87 Umeå, Sweden; 3Agriculture and Agri-Food Canada, ECORC, Ottawa, ON, Canada, K1A 0C6 savitchl@agr.gc.ca; aivanov@uwo.ca; mkrol@uwo.ca; Gunnar.Oquist@plantphys.umu.se; nhuner@uwo.ca Seedlings of Lodgepole pine (Pinus contorta L.) responded to cold acclimation under controlled conditions by partial inhibition of photosynthesis and an associated partial loss of needle chlorophyll content and lower abundance of PSII reaction centers (Savitch et al. 2002 Plant Cell Environ. 25: 761–771). Non-denaturating polyacrylamide gel electrophoresis measurements provided in this study indicates that acclimation to low temperatures has even stronger effect on PSI and the abundance of PSI-chlorophyll protein complexes (LHC1-CP1) is significantly lower compared to PSII related complexes (CPa and LHCII). These data are consistent with the low temperature (77K) chlorophyll fluorescence data indicating a strong reduction of PSI-associated peak centered at 735 nm in cold acclimated pine needles, thus confirming the alteration in the stoichiometry and/or excitation energy distribution between PSI and PSII Chl–protein complexes in cold acclimated relative to control pine plants. In addition, a characteristic blue shift of about 10 nm PSI related fluorescence peak was observed in cold acclimated pine. The estimated energy partitioning of absorbed light to various pathways under ambient CO2 (35 Pa) and O2 (21 KPa) conditions indicated that the fraction utilized by PSII photochemistry (ΦPSII ) was 2-fold lower, while the proportion of thermally dissipated energy through ΦNPQ was almost the same in cold acclimated (5°C) than in control plants. In contrast, Φf,D, i.e. the fraction of absorbed light energy dissipated by additional quenching mechanism(s) was 2-fold higher in cold adapted pine needles. As expected, lowering the O2 concentration to 2 KPa resulted in a sharp decrease of ΦPSII accompanied by significant increase of ΦNPQ in control plants. In contrast, although cold acclimated plants also exhibited decreased

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ΦPSII under low O2 concentration, the fraction of ΦNPQ remained unchanged. However, the fraction of constitutive quenching (Φf,D) in cold acclimated needles was additionally increased by 50% under low O2. This demonstrates that in cold acclimated pine oxygen plays an important role as an electron sink in a process dissipating excess light energy, which is independent from the antenna based non-photochemical quenching. P-105 The use of Group 3 LEA protein fusion partners in facilitating recombinant expression of recalcitrant proteins Johann Schernthaner1, S Whitwill1, G Lacroix1, J Douglas1, G Allard1, W Keller2, L Savitch1, and J Singh1

1ECORC, Agriculture and Agri-Food Canada, Ottawa, ON, K1A 0C6; 2Plant Biotechnology Institute, National Research Council, Saskatoon, SA, S7N 0W9, Canada singhja@agr.gc.ca Late Embryogenesis Abundant (LEA) proteins are intrinsically disordered proteins that accumulate in organisms during the development of dehydration stress tolerance and cold acclimation. Group 3 LEA proteins have been implicated in the prevention of cellular protein denaturation and membrane damage during desiccation and anhydrobiosis. We tested the ability of LEA proteins to act as fusion partners in facilitating recombinant expression of recalcitrant and intrinsic membrane proteins. Two Group 3 LEA proteins, BN115m (a Brassica ortholog of the Arabdopsis COR15) and a truncated fragment of BNECP63 (a Brassica ortholog of the Arabidopsis seed maturation specific ECP63) proteins, were fused to two target proteins identified as recalcitrant to overexpression in soluble form or outside of inclusion bodies in bacteria. Fusion of a truncated peptide of BNECP63 is sufficient to provide soluble and high levels of recombinant overexpression of PsbS (an intrinsic membrane chlorophyll-binding protein of photosystem II light harvesting complex) and a peptide from the E2 fragment of the HepC virus polyprotein. Furthermore, fusion of the recombinant target proteins to BNECP63 or BN115 prevented irreversible heat- and freeze-induced precipitation. These experiments not only underscore the exploitation of LEA-type peptides in facilitating protein overexpression and protection, but also provided insights into the mechanism of LEA proteins in cellular protection. P-106 Functional Characterization of a Gene Upregulated in Embrogenic Brassica napus Microspores F Shahmir and KP Pauls Dept of Plant Agriculture, University of Guelph, Guelph, ON, Canada, N1G 2W1 fshahmir@uoguelph.ca Cultured canola microspores undergo embryogenesis instead of forming pollen when exposed to a mild heat stress. The microspore culture system is useful for studying embryogenesis because microspore-derived embryos are very similar to the zygotic embryos with respect to their morphology, chemical composition and physiology. Therefore, it provides an easy way to access and study all of he different stages of embryogenesis, starting from the initiation phase. Moreover, the similarities make it possible

to use the system to identify a gene that is involved in zygotic embryogenesis. A previous study comparing the transcriptomes of three–day-old sorted embryogenic and pollen-like, (nonemebryogenic) ,cells of B.napus microspore cultures identified 100 transcripts that were upregulated in embryogenic cells, including a fragment of a gene of unkown function homologous to AT1G73740. This objective of the current study is to characterize the homologous gene in B. napus and to determine its function by over-expression and RNA silencing in B. napus and Arabidopsis.The complete gene was isolated and sequenced from B. napus by PCR and RT-PCR using primers designed from the AT1G73740 sequence and named as BnMicEmUP (B. napus microspore embryogenesis up regulated gene). Two forms of BnMicEmUP mRNA (597bp and 588 bp) and two forms of genomic DNA (711bp and 702bp) were identified. These BnMicEmUPs share high nucleotide similarity with AT1G73740 Arabidopsis (about 85%) within the coding region and have a similar genomic organization to the Arabidopsis gene. To investigate the function of BnMicEmUP two silencing constructs were made with the Pfgc5941vector and two different BnMicEmUP fragments. One fragment is highly gene-specific and the other fragment is ~90% identical for the two forms of the gene. Vectors with a 35spromoter (pB1121) and an inducible promoter (pER8) were constructed for over-expression of the BnMicEmUP597 gene. The constructs were delivered by Agrobacterium-mediated transformation of A. thaliana using the floral dip method and Brassica using hypocotyl explants. The effects of gene over–expression and suppression on embryo formation and plant development will be investigated. P-107 Functional ecology of summer dormancy in ‘sandbinding’ roots of Australian native monocots Michael Shane1, H Ngo1, J Pate1, H Lambers1, M McCully2, M Canny3, and C Huang4 1School of Plant Biology, The University of Western Australia, Crawley, 6009, WA, Australia; 2 Plant Industry, CSIRO, Canberra, 2601, ACT, Australia; 3Ecosystem Dynamics Group, Research School of Biological Sciences, Australian National University, Canberra, 0200, ACT, Australia; 4 Electron Microscopy Unit, Research School of Biological Sciences, Australian National University, Canberra, 0200, ACT, Australia mshane@cyllene.uwa.edu.au There are approx. 480 species of Southern Hemisphere Rushes (Restionaceae; ca. 330 in Africa, 150 in Australia, 4 in New Zealand and 1 species in South America). Southern hemisphere rushes are common in the understorey in most areas of temperate Australia, but most species occur in south-western Australia (ca. 120). These plants have to cope with summer soil surface temperatures of 70 ºC and soil moisture content as low as 0.5%. In rushes, “sand-binding” roots have evolved, presumably as an adaptation, to sustain water and nutrient acquisition. Our project aims to integrate formation, structure and functioning of these root structures. We report a novel strategy for root-system survival in an herbaceous perennial rush, Lyginia barbata, native to mediterranean south-western Australia. Root apices become dormant during summer with modified structure and metabolism that allow root stem cells to remain viable. These stem cells, protected by the dormancy, enable resumption of root development (and nutrient and water acquisition) when

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temperature decreases and soil moisture increases in winter. This annual cycle allows the long-lived roots to access deep soil. Our field work suggests that periodic root growth is pivotal for survival for L. barbata and other long-lived ‘grass-like’ native monocots and represents a strategy similar to winter root dormancy in cold-climate trees. P-108 The GLK1 ‘regulon’ encodes disease defense related proteins and confers resistance to Fusarium graminearum in Arabidopsis L Savitch, G Subramaniam, G Allard, and Jas Singh ECORC, Agriculture and Agri-Food Canada, Ottawa, ON, Canada, K1A 0C6 singhja@agr.gc.ca The maize Golden2-like or GLK genes encode proteins belonging to a class of GARP domain transcriptional activators (Rossini et al, 2001, Plant Cell 13:1231). GARP domain transcriptional activators are involved in plant specific processes and GLK has been observed to be involved in the regulation of chloroplast development (Yasumura et al, 2005,Plant Cell 17:1894) and adaptation to cold stress (Savitch et al, 2005, Plant Cell Physiol 46:1525). The in planta targets of GLK regulated transcription, however, have not been identified. We use GLK1 overexpression (OE) to study reprogramming of gene expression networks in Arabidopsis and to identify an associated phenotype. Affymetrix Gene Chip and RT-PCR analyses indicated that GLK1 OE in Arabidopsis reprogrammed gene expression networks to enhance a high constitutive expression of genes encoding disease defense related proteins. These include PR10, isochorismate synthase, antimicrobial peptides, glycosyl hydrolases, MATE efflux and other genes associated with pathogen response and detoxification. However, PR1, an indicator of systemic acquired resistance (SAR), was downregulated in GLK1 OE. GLK1 OE in Arabidopsis confers resistance to Fusarium graminearum, a broad host pathogen responsible for major losses in cereal crops. This is the first identification of the GLK1 ‘regulon’ and a novel role for GLK1 in plant defense, suggesting its potential use for providing disease resistance in crop plants. P-109 A point mutation in the pre-mRNA of F.linearis cytFBPase causes a null mutation due to a cryptic intron SMH Slater and BJ Micallef Dept of Plant Science, University of Guelph, 50Stone Road E, Guelph, ON, Canada, N1G 2W1 sslater@uoguelph.ca Cytosolic fructose 1, 6 bisphosphatase (cytFBPase) is a regulatory enzyme in the glycolytic pathway and controls the movement of carbon between the triose phosphate and hexose phosphate pools. A null mutant for this enzyme, or any enzyme for sucrose synthesis, has never been reported. A Flaveria linearis mutant has a null phenotype for cytFBPase caused by a deletion in the active site. This deletion is due to cryptic splicing, caused by a point mutation in a pre-mRNA acceptor splice site.

P-110 Endoreplication in cucumber (Cucumis sativus L.) seeds at harvest, after storage and controlled deterioration, and during germination M Bartunek and Elwira Sliwinska Dept of Genetics and Plant Breeding, University of Technology and Life Sciences, al. Kaliskiego 7, 85-789 Bydgoszcz, Poland elwira@utp.edu.pl Nuclear DNA endoreplication often occurs during growth and differentiation of the embryo; however, endopolyploidy usually does not occur in the mature embryo. This allows the use of flow cytometry to establish the physiological state of the seed and apply it to optimize harvest time and priming conditions. Fruits of cucumber (Cucumis sativus L.) growing in a seed production field were collected at commercial harvest time. Seeds were isolated and the proportion of nuclei with different DNA contents in the embryo and radicle was established using flow cytometry. The same analyses were performed on the seeds after processing (fermentation, drying and cleaning), after one and two years of storage, following controlled deterioration (CD; 72h at 24% moisture content and 45oC), and at 3, 6 and 12 hours of imbibition. In the fresh mature seeds, the majority of embryo nuclei (slightly below 80%) contained 2C DNA; however, about 4% of endoreduplicated (8C) nuclei were present. After processing, the proportion of 8C decreased below 2%, and further decrease was observed after storage and CD. Upon germination, the proportion of endoreduplicated nuclei gradually increased, up to 3% after 12 h of imbibition. Thus cucumber seeds express polysomaty already in the dry state and the DNA synthesis pattern during germination sensu stricto suggests the preparation of some cells to enter another endocycle. The 4C/2C ratio that is normally used as a marker of advancement of germination of seeds of other species is not appropriate for cucumber, and therefore the 4C+8C/2C ratio must be used instead. P-111 Low temperature exposure and BNCBF overexpression affect SR proteins in Brassica napus plants Dave Sprott1, E Ponomareva1, J Singh1, M Golovkin2, and LV Savitch1

1 Agriculture and Agri-Food Canada, ECORC, Ottawa, ON, Canada, K1A 0C6; 2 Thomas Jefferson University, 1020 Locust St, JAH-369, Philadelphia, PA 19107, USA sprottd@agr.gc.ca; singhja@agr.gc.ca; maxim.golovkin@jefferson.edu; savitchl@agr.gc.ca The molecular response to abiotic stresses in plants is a complex process. It is widely acknowledged that at the core of it lies the transcriptional activity modulation of stress related genes. Recent findings suggested a new layer(s) of regulation at the post-transcriptional, translational and post-translational levels. The comparative analysis of transcriptomes and proteomes together with physiological analysis of transgenic B. napus plants overexpressing CBF/Dreb1 BNCBF 5 and 17 genes, as well as analyses of wild type B. napus response to cold stress and cold acclimation suggested that post-transcriptional regulation has an important role in cold stress tolerance and cold acclimation of this plant. We further showed that

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representation of a large number of proteins encoded by the genes related to transcription/translation has significantly increased (27% to 42%) in response to low temperature exposure and BNCBF overexpression. Moreover, low temperatures has a prominent effect on the number of proteins (~ 26) related to pre-mRNA splicing and RNA stabilization. Among them are the Serine/Arginine-rich (SR) proteins that are essential for constitutive and alternative splicing and possibly play other functions in eukaryotic cells. Western blot and RT-PCR analyses showed that low temperatures decreased levels of four SC35- and one SF2-type SR transcripts and the corresponding proteins; while low temperatures increased levels of three 9G8- and two other “plant specific” SR transcripts and proteins. This pattern was observed in WT and BNCBF OE B.napus plants. Interestingly, the increase in amounts of one of the 9G8- and two of the “plant specific”- SR transcripts and proteins was observed in BNCBF5 and 17 OE even without cold stress and/or cold acclimation that suggesting BNCBF can partially mimic the low temperature in SR regulation. In addition, the western blot analysis recognized that two the “plant specific”-type of SR proteins were affected in their phosphorylation modus only in BNCBF OE and not in WT plants/ WT plants subjected to cold stress/acclimation. To our knowledge, this is the first report to investigate the multi-level effect of CBF/Dreb1 overexpression on splicing-related SR gene activity and SR protein accumulation in plants. The functional interpretation of all these results and the role of mRNA splicing in cold acclimation is discussed. P-112 Is the function of the microtubule end binding protein EB1 linked to auxin? Shannon Squires and S Bisgrove Dept of Biological Sciences, Simon Fraser University, BC, Canada ssquirea@sfu.ca Plants are sessile and must adapt to environmental conditions by altering their growth. At the cellular level, changes in growth involve cell division and elongation. These processes require the involvement of microtubules (MTs), which are regulated by MT associated proteins (MAPs). To understand how MTs influence growth and development, I am studying a MAP, End Binding 1 (EB1). There are three EB1 genes in the Arabidopsis thaliana genome. Plants carrying mutations in each of the ateb1 genes, as well as a triple mutant, were studied. Ateb1 mutant roots form loops and have delayed responses to touch and gravity. These growth responses are regulated by the plant hormone auxin. To test if the function of EB1 is linked to auxin, plants were grown on different concentrations of chemicals that inhibit polar auxin transport and auxin signaling. I measured root lengths, proportions of roots forming loops, and root angles. I found that root elongation decreased by a similar amount in all genotypes. However, two of the ateb1 mutants (ateb1b-1 and the triple mutant) formed more loops, and grew at a greater angle than the wild type in the presence of inhibitors. This suggests that the ateb1 mutants are more sensitive to inhibitors of auxin transport and signaling.

P-113 Arabidopsis ribosomal protein S15a isoform localization in tobacco and RNAi induced silencing of each gene in Arabidopsis Chad Stewart, H Wakely, J Hulm, and P Bonham-Smith 112 Science Place, Saskatoon, SK, Canada cdstewart2003@yahoo.ca The ribosome is a large complex enzyme comprised of two subunits (60S large subunit and 40S small subunit), four ribosomal RNAs (rRNAs) and a multitude of ribosomal proteins (r-proteins), essential for protein synthesis. In Arabidopsis, 254 genes encode 81 r-proteins with gene families containing between two to five actively expressed members. RPS15a, a small subunit r-protein gene family, consists of six members, A-F, with only one member, RPS15aC, not expressed. RPS15a isoform cellular localization (nuclear, nucleolar or mitochondrial) was determined using transient infiltration in tobacco followed by visualization by confocal microscopy. RPS15aA/ –D/ and –F (type I proteins) all localized to the nucleolous whereas RPS15aB and RPS15aE (type II proteins) localized to mitochondria. Results from competitive localization experiments with different isoforms of the protein will be presented. An estrogen inducible RNA interference (RNAi) system will be used to silence each RPS15a gene individually, as well as, all type I (cytoplasmic) and type II (mitochondrial) RPS15a’s. To decrease the possibility of cross silencing between family members sequence from the 3’ untranslated region (UTR: 150-200 bp fragments) were used in the design of the hairpin RNA (hpRNA) constructs for silencing individual genes. To silence each clade individually a 300-400 base pair fragment of the RPS15aA and RPS15aE open reading frames (ORFs) were used as they showed the highest degree of sequence similarity between the members of each clade. Results from RNAi silencing will be presented. P-114 Identification of thylakoid membrane phospho-proteins in an Antarctic psychrophilic alga, Chlamydomonas raudensis UWO 241 B Szyszka and NPA Hüner University of Western Ontario, 1151 Richmond St, B&G 232, London, ON, Canada, N6A 5B8 bszyszka@uwo.ca Chlamydomonas raudensis UWO 241 is a photosynthetic green alga isolated from the permanently ice-covered Lake Bonney in Antarctica. This unique psychrophile is adapted to an extremely stable environment of low temperatures and low irradiance. Previous studies have shown that C. raudensis UWO 241 is the first natural variant deficient in the state transition response. This Antarctic strain is locked and state I and unable to redistribute light energy among photosystem I and photosystem II. In addition, C. raudensis UWO 241 exhibits a unique phosphorylation profile with phosphorylation of a group of high molecular mass polypeptides on threonine residues and the absence of phosphorylation of typical photosystem II – related polypeptides. Thus, it is hypothesized that this Antarctic strain may exhibit phosphorylation of photosystem I. In order to identify these phospho-proteins and the complexes from which they

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originate, two dimensional blue native polyacrylamide gel electrophoresis (BN-PAGE) was used. Immunoblot analysis of the second dimension with phospho-threonine antibodies revealed the phosphorylation of a large (115-170 kDa) complex closely associated with photosystemI. To further examine whether phosphorylation is related to photosystem I, fractionation of thylakoid membrane complexes was performed by sucrose density gradients. Subsequent studies will investigate whether these phospho-proteins originate from photosystem I using a purified fraction of this complex. P-115 Similar mechanism to trichome pathway is involved in peach fruit development Taheri1 A, S Jayasankar2, J Cline2, KP Pauls1, and MN Raizada1 1Dept of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, ON, Canada, N1G 2W1; 2Dept of Plant Agriculture, University of Guelph, 4890 Victoria Ave, Box 7000, Vineland Station, ON, Canada, L0R 2E0 ataheri@uoguelph.ca The main phenotypic difference between peach and nectarine is in the hairiness of peach fruit (fuzz) and the single gene responsible for this trait have been mapped in 41-45cM of chromosome five in Prunus reference map using a mapping population from a cross between P. Persica cv. ‘Ferjalou Jalousia’ (peach) and P. Persica cv. ‘Fantasia’ (nectarine). We hypothesised that homologous genes to trichome pathway are involved in the control of peach fuzz. Primers were designed form the conserved region of TRANSPARENT TESTA GLABRA1 (TTG1) and Glabra2 (GL2) by multiple alignments of homologous genes available in NCBI genebank database. PCR fragments amplified with the primers were cloned and sequenced. Plasmid DNA from a BAC clone located at 41-45cM in chromosome five of peach was extracted and used as template in PCR reaction along with TTG1 primers. A fragment similar to TTG1 was amplified from this BAC clone. Restriction digestion pattern of these fragments were similar in peach genomic DNA and BAC clone PCR. Sequencing results confirmed that these two fragments are the same. Full length Peach TTG1 was also used in transformation of ttg1 arabidopsis mutant and it was able to complement this mutant, successfully restoring the lost function. Following genome walking and 3’RACE techniques, full length TTG1 and its promoter were cloned from both peach and nectarine. Further gene expression studies are in progress. P-116 Isolation and genetic manipulation of D-cysteine desulfhydrase from Solanum lycopersicum Biljana Todorovic and BR Glick 79 Lorraine Ave, Kitchener, ON, Canada, N2B 2N1 btodorov@uwaterloo.ca Progress in DNA sequencing of plant genomes has revealed that, in addition to microorganisms, a number of plants contain genes which share similarity to microbial 1-aminocyclopropane-1-carboxylate (ACC) deaminases. ACC deaminases break down ACC, the immediate precursor of ethylene in plants, into ammonia and α-ketobutyrate. We therefore sought to isolate putative ACC

deaminase cDNAs from tomato plants with the objective of establishing whether the product of this gene is a functional ACC deaminase. It was demonstrated that the enzyme encoded by the putative ACC deaminase cDNA does not have the ability to break the cyclopropane ring of ACC, but rather that it utilizes D-cysteine as a substrate, and in fact encodes a D-cysteine desulfhydrase. Kinetic characterization of the enzyme has shown that it is similar to other previously characterized D-cysteine desulfhy-drases. Using site-directed mutagenesis, it was shown that altering two amino acid residues within the predicted active site changed the enzyme from D-cysteine desulfhy-drase to ACC deaminase. Concomitantly, it was shown that by altering two amino acids residues at the same position within the active site of ACC deaminase from Pseudomonas putida UW4 changed this enzyme into D-cysteine desulfhydrase. P-117 Differentially glycosylated and kinetically distinct isoforms of the purple acid phosphatase AtPAP26 are secreted by phosphate-starved Arabidopsis thaliana suspension cells Hue T Tran and WC Plaxton Dept of Biology, Queen’s University, Kingston, ON, canada, K7L 3N6 4htt@queensu.ca Phosphate (Pi) is one of the least available macronutrients in many ecosystems. Most soil P exists as organic phosphate-esters unavailable for root uptake until Pi hydrolysis by secreted acid phosphatase occurs. Three secreted purple acid phosphatase (PAP) isoforms were purified from culture filtrates of Pi-starved (-Pi) Arabidopsis suspension cells. MALDI-TOF MS identified them as a homodimeric AtPAP12 (At2g27190, 65-kDa subunits), and 2 monomeric AtPAP26 isoforms (AtPAP26S1 & AtPAP26S2; At5g34850, 55-kDa subunits). Immunoblotting indicated that AtPAP12 and AtPAP26 were also secreted by roots of –Pi, but not Pi-sufficient, Arabidopsis seedlings. Their combined activities may allow –Pi Arabidopsis to scavenge Pi from a wide range of extracellular P-esters over a broad pH. The N-terminal sequences of AtPAP26S1 and AtPAP26S2 were identical to that of a vacuolar AtPAP26 isoform that is also upregulated by –Pi Arabidopsis (2006 Plant Physiol 142:1282). Although Pro-Q Emerald staining demonstrated that each of the secreted PAPs is glycosylated, (i) AtPAP26S1 was not bound by Concanavalin-A Sepharose, whereas AtPAP26S2 was absorbed by this lectin-affinity column (and eluted by ~50 mM α-methyl D-mannoside), and (ii) Concanavalin-A or soybean lectin activated AtPAP26S2, but exerted no influence on AtPAP26S1 activity. These discrepancies are attributed to differential glycosylation of AtPAP26S1 and AtPAP26S2, details of which are currently being investigated. Glycosylation may influence an enzyme's compartmentation, structure, activity, and/or proteolytic susceptibility. Our results indicate that differential glycosylation of AtPAP26 represents a novel post-translational modification that controls the activity and subcellular targeting of this important Pi-scavenging enzyme in -Pi Arabidopsis.

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P-118 The Characterization of a novel polyphenol oxidase in poplar Lan T Tran and CP Constabel Centre for Forest Biology and Dept of Biology, University of Victoria, PO Box 3020, Station CSC, Victoria, BC, Canada, V8W 3N5 lttran@uvic.ca Polyphenol oxidases (PPOs) catalyze oxidative browning reactions in plants by converting phenols to quinones in the presence of molecular oxygen. The physiological functions associated with this ubiquitous enzyme are diverse. Typically, PPOs are thought to help mediate defense against herbivores and pathogens via the reactive quinone products but biosynthetic functions have also been demonstrated. Although PPOs are nuclear-encoded, they typically contain a transit peptide for chloroplast localization. Bioinformatic analysis of the Populus trichocarpa genome has resulted in the identification of approximately nine PPO genes. Interestingly, one PPO gene appears not to encode an N-terminal transit peptide commonly found in plant PPOs and may therefore be localized to a different organelle. The goal of this research is to characterize the subcellular localization of this novel PPO using transient Agrobacterium-mediated gene expression in Nicotiana benthamiana using green fluorescent protein fusions. Many PPOs are known to exhibit spatial and temporal patterns of expression that reflect specialized functions. Gene expression will also be studied to analyze the expression of PPOs in a number of poplar organs and tissues during normal development. Together, gene expression profiling and subcellular localization studies may provide an indication of a biological function and contribute new insight into PPOs in plants. P-119 Poplar glycosyltransferases induced under patho-gen attack Vasko Veljanovski and CP Constabel Centre for Forest Biology, Dept of Biology, University of Victoria, BC, Canada, V8W 3N5 vasko@uvic.ca Glycosylation involves the transfer of a sugar residue from a donor molecule to an acceptor molecule and is often one of the last steps involved in the biosynthesis of various plant defense compounds including anthocyanins and flavonoids. It is believed that glycosylation of these compounds influences their stability and biological activity. Furthermore, the addition of sugars may be crucial for the targeting of compounds to specific compartments within a cell. Glycosylation is catalyzed by an extensive group of enzymes known as glycosyltransferases. A specific subgroup, the uridine diphosphate glycosyltransferases (UGTs), transfer sugars that are attached to a UDP molecule. Recently in microarray experiments on poplar tissue, a number of flavonoid-specific UGT genes were highly upregulated after infection with Melampsora rust. It seems that these proteins may be important for plant defense, yet very little is known about them within poplar. To date, we have generated recombinant UGT proteins for two highly induced genes. We are currently in the process of testing the activity of these enzymes with a wide range of flavonoid substrates using a variety of techniques. We

are also in the process of using RNA interference (RNAi) to suppress the expression of poplar UGTs to further investigate their effects on plant defense. Overall we hope to determine how UGTs are involved in a plant’s defense response. P-120 Characterization of enhancers of mucilage modified4 Maria M Villota1,3, N Martin2, TL Western2, G Subramanian3, and O Rowland1 1Biology Dept, Carleton University, Ottawa, ON; 2Biology Dept, McGill University, Montréal, QC; 3ECORC 960 Carling Ave, Ottawa, ON, K1A 0C6, Canada, maria@acero.ca Mucilage is a complex hydrophilic polysaccharide produced in the epidermal cells of the seed coat in various plant families such as the Brassicaceae, Solanaceae, Linaceae, and Plantaginaceae. Its release upon imbibition provides a gel-like coating that surrounds the seed, facilitating its dispersal, hydration, and germination. The biosynthesis and secretion of mucilage in the seed coat proceeds through at least three predicted pathways, two of them dependent on APETALA2, while another involves AtMYB61. A key enzyme in one of these pathways is MUCILAGE MODIFIED4 (MUM4), which encodes a putative NDP-L-rhamnose synthase required for mucilage biosynthesis. Mucilage synthesis is coupled to its secretion to the apoplast, forming a ring-shaped mucilage pocket that appears to constrict the top portion of the cytoplasm. mum4 mutants have reduced mucilage accumulation in the extracellular space and consequent altered cellular appearance. To further investigate the regulation of MUM4, an enhancer/suppressor screen was performed that identified several putative enhancer lines, known as mum enhancers (men). men mum4 double mutant lines are being characterized to determine the effect of the enhancer mutations on germination, pathogen resistance and a battery of plant developmental characters. Further, we are in the process of mapping MEN2, which has been localized to the bottom of Chromosome I. P-121 Putative aquaporin transcript levels and the light response of leaf hydraulic conductance in bur oak (Quercus macrocarpa Michx.) Mihaela C Voicu1, JEK Cooke2, and JJ Zwiazek1 14-42 ESB, Dept of Renewable Resources, University of Alberta, Edmonton, AB, Canada, T6G 2E3; 2CW 460, Biological Sciences Bldg, University of Alberta, Edmonton, AB, Canada, T6G 2E9 mvoicu@ualberta.ca Water flow across different plant tissues can be rapidly modulated by the presence and activity of aquaporins. However, little is known about the contribution of aquaporins to water movement in leaves. We have previously shown that in bur oak leaves (Quercus macrocarpa Michx.), the hydraulic conductance, when measured with the high pressure flowmeter technique (HPFM), can significantly increase within 30 min following exposure to high irradiance (the light response). The present study investigated whether this increase is linked to an increase in the transcript level corresponding to aquaporin genes. Four cDNA sequences showing high sequence similarity to members of aquaporin gene family

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from other species were characterized from bur oak leaves. Phylogenetic analysis of the corresponding amino acid sequences provide strong evidence that they belong to the aquaporin gene family of water-channel proteins localized in the plasma membrane. To investigate the aquaporin contribution to the increase of leaf hydraulic conductance in high irradiance, the relative amount of these putative aquaporin transcripts were determined using QRT-PCR. The hydraulic conductance of leaves that were subjected to the HPFM measurements, increased 7 times in high irradiance. However, for the same leaves, there was no change in the relative expression level of putative aquaporin genes between the leaves with light-induced high hydraulic conductance (high irradiance) and leaves with low hydraulic conductance (low irradiance). We further investigated the aquaporin gene expression in leaves that were exposed to different light levels prior to collection (full sunlight – sun-adapted, shade –shade-adapted, and covered with aluminum foil – dark-adapted leaves). The relative transcript level of two of the putative aquaporin genes increased several times in shade-adapted leaves as opposed to the sun- or dark-adapted leaves. The results suggest that the putative aquaporin genes that were identified in the present study likely do not play a role in the light responses of hydraulic conductance at the transcript level. However, they are probably important in regulating water homeostasis in leaves adapted to different light conditions. P-122 RNA Binding Characteristics of Different Isoforms of Arabidopsis thaliana Ribosomal Protein S15a Heather Wakely and PC Bonham-Smith Dept of Biology, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5E2 hew787@mail.usask.ca Ribosomes, which carry out protein synthesis in all living organisms, are comprised of two subunits. The Arabidopsis thaliana 80S cytoplasmic ribosome is composed of 4 ribosomal RNAs (rRNAs: 26S, 5.8S and 5S in the large subunit and 18S in the small subunit) and 81 ribosomal proteins (RPs: 48 in the large subunit, 33 in the small subunit). RPS15a, a putative small subunit primary binder, is encoded by a 6 member gene family (RPS15aA-F), where RPS15aB and RPS15aE are evolutionarily distinct and thought to be incorporated into mitochondrial ribosomes. In vitro synthesized cytoplasmic 18S rRNA, 18S rRNA loop fragments, and RPS15a mRNA molecules were combined in electromobility shift assays (EMSAs) to determine the RNA binding characteristics of RPS15aA/-D/-E/-F. RPS15aA/-D/-E-F binds to 18S rRNA in the absence of cellular components. RPS15aA/F binds one of three 18S rRNA loop fragments whereas RPS15aD/-E binds all three 18S rRNA loop fragments. Additionally, RPS15aD and RPS15aE did not bind their respective mRNA transcripts, likely indicating that this form of negative feedback is not a post transcriptional control mechanism for this RP gene family. Furthermore, the addition of RPS15a transcripts to the EMSAs does not affect the binding of RPS15aD and RPS15aE to 18S rRNA loop fragments, indicating that the rRNA binding is specific. These data support a role for RPS15a in early ribosome assembly.

P-123 A role for tetrahydrofolate in the metabolism of iron-sulfur clusters in all kingdoms of life Jeffrey C Waller†, V Naponelli* , IK Blaby‡, BL Lyons‡, V Da Silva*, MJ Ziemak*, SM Beverley§, JF Gregory III*, V de Crécy-Lagard‡, and AD Hanson† *Food Science and Human Nutrition,†Horticultural Sciences & Microbiology and Cell Science Depts‡, University of Florida, Gainesville, FL 32611; and §Dept of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110 wallerj@ufl.edu Folates are known principally as cofactors in one-carbon (C1) transfer reactions. The widely-occurring COG0354 protein is therefore intriguing. It is structurally similar to tetrahydrofolate-dependent proteins that capture formaldehyde moieties (e.g., the glycine cleavage complex T protein and dimethylglycine oxidase) and has a folate binding site. Yet it has been implicated in the assembly and regeneration of iron-sulfur (Fe-S) clusters, processes that are apparently unrelated to C1 transfer. Comparative analysis of prokaryote genomes strongly implies the existence of functional connections between COG0354, folate, and Fe-S cluster metabolism: in archaea, only folate-containing organisms have COG0354 genes, and in bacteria COG0354 genes are clustered with genes specifying various Fe-S proteins. A mutational approach in Escherichia coli was used to probe the role of folate in COG0354. Deleting the COG0354 gene (ygfZ) greatly reduced the activities of the Fe-S enzymes MiaB and aconitase. A similar reduction in MiaB activity was seen in a folE (GTP cyclohydrolase I) deletant, which lacks folates. The ygfZ deletion caused hypersensitivity to oxidative stress and failure to grow on glycerol or acetate as carbon source. Plasmid-borne COG0354 genes of archaeal, fun-gal, protistan, or animal origin complemented one or both of these growth phenotypes. However, only the Arabidopsis mitochondrial YgfZ homologue, AtYgfZ1, and not the plastidial homologue, AtYgfZ2, could complement the E. coli ygfZ deletant. Furthermore, the atygfz1 mutation was found to be a recessive embryo-lethal. Collectively, these results indicate that COG0354 has an ancient function that requires folate. P-124 The role of the mitochondrion and alternative oxidase during low temperature growth in Nicotiana tabacum Steven Wang, S Amirsadeghi, and GC Vanlerberghe Dept of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, Canada, M1C 1A4 jiawang@utsc.utoronto.ca The plant mitochondrial electron transport chain (ETC) includes a non-energy conserving alternative oxidase (AOX), the expression of which may be higher at low growth temperatures. While it has been hypothesized that AOX may act to facilitate carbon metabolism and / or dampen reactive oxygen species (ROS) generation by the mitochondrial ETC at low temperature, a direct investigation of either of these roles is lacking. To study the potential role of AOX at low temperature, we have compared wild-type Nicotiana tabacum plants to transgenic plants in which AOX expression has been silenced by introduction of a RNA interference construct.

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For this comparison, plants were initially grown at a day/night temperature of 28°C/22°C and then shifted to a temperature of 12°C/5°C for up to 72 h. In wt plants, the temperature shift induced a large increase in AOX mRNA and protein within 24 h. This was accompanied over the 72 h period by a large increase in the pool size of glucose and fructose, along with a small increase in sucrose and starch. However, we found no evidence that the size of these carbohydrate pools was higher in plants lacking AOX (either before or after the temperature shift) and rather the pool size of monosaccharides was actually lower in plants lacking AOX than in the wt by 72 h after the temperature shift. An in situ staining method was used to evaluate leaf levels of superoxide and H2O2. At the relatively low light intensities used in our experiments (130 µmol m-2 s-1), the levels of both ROS species were similar in wt and transgenic plants growing at 28°C/22°C and both sets of plants showed similar levels of ROS-scavenging enzymes. We did however observe a higher level of oxidative damage (lipid peroxidation) in the transgenic plants at this temperature. Interestingly, after transfer to low temperature, the levels of ROS and lipid peroxidation became lower in the transgenic plants lacking AOX than in the wt. Meanwhile, the expression and activity of key ROS-scavenging enzymes increased in both wt and transgenic plants after the low temperature shift and this increase was more dramatic in the plants lacking AOX. Our results indicate that the mitochondrion and AOX do indeed influence carbon metabolism and ROS metabolism, particularly after the shift to low temperature. However, more experimentation is needed to fully understand the ramifications of the lack of AOX. P-125 Bioavailability of iron bound to strong chelators – Interspecific differences Harold G Weger1, CJ Matz1,3, CN Walker1, MB Fink1, and RG Treble2 1Dept of Biology, University of Regina, Regina, SK, S4S 0A2; 2Dept of Chemistry & Biochemistry, Univ of Regina, Regina, SK, S4S 0A2; 3Present: Toxicology Centre, Univ of Saskatchewan, Saskatoon, SK, S7N 5E5 harold.weger@uregina.ca N,N’-di(2-hydroxybenzoyl)-ethylenediamine-N,N’-diacetic acid [HBED] is a very strong Fe3+ chelator. Strategy I vascular plants, which use a reductive system for iron acquisition, similar to many green algae, are able to access iron from HBED (Chaney RL [1988] J Plant Nutr 11:1033). However, iron-limited cells of the Strategy I green alga Chlamydomonas reinhardtii Dangeard were unable to access iron present as Fe3+-HBED. In contrast, Fe3+ chelated with HEDTA (a weaker chelator) was rapidly taken up by iron-limited Chlamydomonas cells. Chlamydomonas ferric reduction rates with Fe3+-HBED was approximately 15% of the rate observed with Fe3+-HEDTA, suggesting that low reduction rates with Fe3+-HBED might be one factor in the low rate of iron acquisition. By contrast, iron-limited cells of the Strategy I green alga Chlorella kessleri Fott et Nováková were able to rapidly assimilate Fe3+ chelated by HBED, although ferric reduction rates with Fe3+-HBED were approximately 38% the rate of activity with Fe3+-HEDTA. Similar differential iron uptake rates for the two algal species were obtained using the strong Fe3+ chelator (and siderophore analogue) DFB

mesylate and the cyanobacterial siderophore schizokinen. These results suggest that there are differences among Strategy I green algae in their abilities to acquire Fe3+ from various ferric chelates: not all Strategy I algae can equally access tightly complexed Fe3+. Chlamydomonas appears to be the first documented Strategy I organism that is unable to acquire iron from Fe3+-HBED. These results also suggest that green algal iron acquisition from siderophores is species-dependent. Finally, we suggest that iron acquisition from Fe3+-HBED might serve as an assay for an organisms’ ability to access tightly complexed iron. P-126 The biogenesis of cytoplasmic membranous vesicles for virus replication in plants requires AtSYP71, a SNARE protein Taiyun Wei and A Wang Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, London, ON, Canada, N5V 4T3 weit@agr.gc.ca All positive sense RNA viruses including plant potyviruses induce the formation of cytoplasmic membranous vesicles for genome replication. However, the mechanisms that underlie the biogenesis of such specific functional entities still remain poorly understood. Previous studies have shown that the plant potyvirus 6 kDa protein (6K or 6K2) is an integral membrane protein and associates with large vesicles derived from the endoplasmic reticulum (ER). In this study, a superfamily of proteins known as SNAREs [soluble NSF (N-ethylmaleimide-sensitive factor) attach-ment protein receptors] that mediates specific vesicle fusion during vesicular transport for the intracellular trafficking of proteins, membrane material and soluble cargo was investigated for the possible involvement in the 6K vesicle production process. By means of live cell imaging, we identified a SNARE protein, AtSYP71 that specifically associated with the Turnip mosaic virus (TuMV) 6K-induced large vesicles. In Nicotiana benthamiana leaves, AtSYP71 adhered to the surface of the 6K large vesicle in the presence or absence of other viral proteins. Fruthermore, the fusion of the 6K large vesicles was strongly suppressed by co-expressing a Sp2 fragment of AtSYP71, a dominant-negative mutant that produced a cytosolic (so-called Sp2) fragment of AtSYP71. Thus, AtSYP71 plays an essential role in the biogenesis of cytoplasmic membranous vesicles for virus replication in plants. P-127 Molecular and physiological analyses for Arabi-dopsis thaliana transgenic lines having altered expression levels of mitochondrial pyruvate de-hydrogenase kinase SM Weraduwage, S Rauf, MC Micallef, B Grodzinski and BJ Micallef Dept of Plant Agriculture, University of Guelph, Guelph, ON, Canada, N1G 2W1 sweraduw@uoguelph.ca Previous work has shown increased mitochondrial pyruvate dehydrogenase (mtPDH) activity, increased rates of dark respiration, increased seed oil content and seed weight in transgenic Arabidopsis having antisense repression of mitochondrial pyruvate dehydrogenase kinase (mtPDHK). These data suggest that a reduction in the negative regulation of mtPDH by antisense mtPDHK expression can

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alter metabolic carbon flux and thereby modify sink activity in plants. These Arabidopsis transgenics also showed enhanced growth rates and productivity compared to controls under elevated CO2 levels in a growth analysis carried out in 2007. Larger harvest indices in transgenic lines indicated an increased capacity to utilize photosynthates more efficiently under elevated CO2 levels compared to the wild type. We hypothesize that the largest increase in vegetative growth and plant productivity under elevated CO2 are shown by Arabidopsis transgenic lines having relatively moderate decreases in mtPDHK expression levels and moderate increases in dark respiratory rates due to antisense repression of mtPDHK. At present, quantitative mRNA-PCR of mtPDHK is being carried out in order to further characterize the Arabidopsis transgenic lines based on their expression levels of mtPDHK. Northern analysis of antisense PDHK expression is also being performed to quantify the expression patterns of the antisense construct in constitutive and seed specific lines. An enzyme assay to determine mtPDH activity in crude extracts of Arabidopsis tissue is also being developed. Whole plant dark respiratory rates will be measured using a 6-chamber gas exchange system. Results of this study will reveal the effect of anabolic properties of dark respiration on sink activity and would provide means to improve plant productivity under elevated CO2 levels. P-128 An in vivo study of developmental Programmed Cell Death (PCD) using the novel lace plant (Aponogeton madagascariensis) model system Harrison Wright and A Gunawardena 373 Hubbard Mountain Rd, Canning, NS, Canada, B0P 1H0 043005w@acadiau.ca The aquatic lace plant’s relative transparency, thinness and unique morphological traits make it an excellent model of developmental PCD. During the ‘window formation’ stage of lace plant growth, discrete populations of cells (centre cells), enclosed by longitudinal and transverse veins, die while those within 5 cell layers of the surrounding vascular tissue (control cells) do not. Both light and transmission electron microscopy were used to better understand the development PCD sequence in this novel system. Cell expansion in the control cells was periclinal to the veins while centre cells became flattened as they were pulled in all directions. Dumbbell shaped chloroplasts, typical during division, persisted until the late stages of PCD; however, the average size and number of chloroplasts, as well as the starch granules associated with them, declined steadily over the course of PCD (p < 0.001). The number of cytoplasmic strands observed increased than decreased over the course of PCD (p < 0.001). The nucleus size decreased relative to PCD maturity (p < 0.001). The rate of mitochondria streaming was sustained during PCD, but appeared to cease during the very late stages, apparently coinciding with tonoplast rupture, shortly before a rapid degradation of the nucleus and plasmolysis. The number of objects located in the vacuoles, identified as chloroplasts, increased relative to PCD maturity in centre cells (p < 0.001), but was rarely observed in control cells. Interestingly, in detached leaves that continued to grow while floated in distilled water, this form of autophagy in the control cells increased with time, apparently as a result of low-nutrient stress, not developmental PCD, but to a lesser degree than observed in the centre cells (p <

0.001). The findings and questions raised in this study provide a rich environment for the continued study of developmental PCD using the lace plant as a model system. P-129 A chalcone synthase-like gene is highly expressed in the tapetum of both wheat (Triticum aestivum L.) and triticale (x Triticosecale Wittmack) Shaobo Wu1, S O’Leary1, A Laroche2, F Eudes2, S Gleddie1 , and LS Robert1 1ECORC, Agriculture and Agri-Food Canada, Ottawa, ON, K1A 0C6; 2Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada wus@agr.gc.ca A wheat chalcone synthase-like gene, TaCHSL1, was isolated from an anther cDNA library by differential screening. The TaCHSL1 transcript was only detected in anthers and, more specifically, within the tapetum during the “free” and early vacuolated microspore stages in both wheat and triticale. Sequence analysis indicated that the 41.8 kDa TaCHSL1 deduced protein belongs to a small distinct group of type III polyketide synthases that includes angiosperm and gymnosperm orthologs shown to be anther-specific. TaCHSL1 sequence characteristics and conservation, as well as its restricted expression pattern, point to a distinct and important biochemical role in developing anthers. P-130 The role of Will Die Slowly 1 (WDS1) gene in the development and defense response of Arabidopsis thaliana X Xiong, S Sun, Paul Nagy, T Abd El Halim, V Abd El Halim, and Tim Xing Dept of Biology, Carleton University, Ottawa, ON, Canada, K1S 5B6 tim_xing@carleton.ca Programmed cell death (PCD) is a form of cellular suicide and involves a set of biochemical programs during the development of organisms and in their responses to pathogen attacks and other stress signals. We have isolated and characterized the Will Die Slowly 1 (WDS1) gene of Arabidopsis thaliana, which encodes a 63kD protein similar to the Will Die Slowly (WDS) protein of Drosophila melanogaster. Real-time PCR reveals that the expression of the gene modulated at different developmental stages, reaching a peak when 50% flowers have open. Analyses on the phenotypes of three T-DNA knockout wds1 mutants indicate that WDS1 is not essential for development of Arabidopsis. However, knockout of WDS1 accelerates the induction of SAG12 expression triggered by FB1, suggesting a regulatory role of WDS1 in stress-induced senescence. WDS1 expression is up-regulated by salicylic acid (SA) and overexpression of WDS1 in Arabidopsis enhances the tolerance to osmotic stress. Our results support the hypothesis of WDS1 as a regulator for cell death progression triggered by both developmental and stress signals in Arabidopsis.

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P-131 Early activation of PM H+-ATPase and its relation to osmotic adjustment and dehydraulic adaptation in two contrasting oat cultivars (Avena sativa L.) You-Cai Xiong1,2,3, B-L Ma2, M-B Yang3, X-L Qin1, X-Q Zhong1, P-F Li1, H-Y Kong1, and F-M Li1* 1MOE Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000, Gansu, PR China; 2ECORC, Agriculture & Agri-Food, Canada, 960 Carling Ave, Ottawa, ON, Canada, K1A 0C6; 3MOE Key Laboratory of Biodiversity and Ecological Engineering, Beijing Normal University, Beijing 100875, PR China mab@agr.gc.ca, fmli@lzu.edu.cn Pot-culture experiments were carried out to determine oat (Avena sativa L.) genotypic differences in water maintenance, osmotic adjustment and activity of plasma membrane (PM) H+-ATPase during the seedling stage. Two oat genotypes with contrasting characteristics in drought sensitivity, Dingyou6 (A. vernasativa, drought-tolerant type) and Bende (A. venanuda, drought-sensitive type) were subjected to soil drought stress under environment-controlled growth chamber conditions. The soil relative water content in pots was maintained at up to 65% (control), 45% (mild stress), 35% (Intermediate stress) and 20% (Serious stress) on the 0, 4, 7 and 14 d after emergence, respectively. At 21-d after emergence, pot water supply was withheld to allow the occurrence of seedlings wilting slightly or severely. Our results showed that Dingyou6 maintained significantly greater water content in its roots and leaves with larger root-to-leaf ratios of RWC and osmotic potential than drought-sensitive Bende, suggesting that drought-tolerant genotypes possesses superior root-to-leaf hydraulic conductivity, and the root system had stronger ability to regulate the water status of aboveground parts. Analysis of the PM H+-ATPase activity and the content of osmotic adjustment chemicals provided chemical evidence for this result. Under mild or intermediate stress conditions, the rate of increase in root PM H+-ATPase activity, and the contents and rates of increase in leaf proline and glycinebetaine, two major osmotic adjustment chemicals, were higher in Dingyou6 than those of Bende. Results of this study imply that early response of plants to soil drought stimuli might play a critical regulatory role in the improvement of osmotic adjustment and the enhancement of drought tolerance. Thus, our study provided a potential theoretical approach to develop oat genotypes with superior tolerance to drought stress, great water use efficiency and high yield potentials for semi-arid regions. P-132 Molecular mapping of genes involved in the phenylpropanoid pathway in common bean (Phaseolus vulgaris L.) Z Yadegari and KP Pauls Dept of Plant Agriculture, University of Guelph, Guelph, ON, Canada, N1G2W1 zyadegar@uoguelph.ca Previous genetic analyses identified 15 genes that control seed coat pattern and color in common bean (Phaseolus vulgaris L.). Some of these genes have been positioned on the common bean linkage map. It has been hypothesized that genes involved in the phenylpropanoid pathway

correspond to some of the classical seed coat color genes in bean. In a previous study we cloned and sequenced fragments of thirty-five phenylpropanoid pathway genes from common bean. The purpose of the current work is to map the positions of these genes on the common bean linkage map and determine whether their position correspond to any of the loci for classical seed coat color genes. The mapping population that was used consisted of recombinant inbred (RI) lines derived from a cross between ‘BAT 93’ and ‘Jalo EEP558’. Polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLP) were identified for the phenylpropanoid gene sequences between parental lines. The segregation patterns of 22 phenylpropanoid pathway genes have been analyzed in the RI population and their locations in the bean linkage map were determined by a JoinMap analysis. The additional genes in this pathway will be mapped in a similar way and cosegregation between phenylpropanoid and classical seed coat color genes will be tested. P-133 Expression of photosynthetic genes in developing leaves in the single-cell C4 species Bienertia sinuspersici Makoto Yanagisawa1, EV Voznesenskaya2, NK Koteyeva2, GE Edwards3, and SDX Chuong1* 1Dept of Biology, University of Waterloo, Waterloo, ON, Canada, N2L 3G1; 2Laboratory of Anatomy and Morphology, VL Komarov Botanical Institute of Russian Academy of Sciences, Prof. Popov Street 2, 197376, St Peterburg, Russia; 3School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA schuong@scimail.uwaterloo.ca Bienertia sinuspersici has been shown to perform C4 photosynthesis within a single chlorenchyma cell. This is achieved by spatial compartmentation of organelles and enzymes into peripheral (PC) and central cytoplasmic (CCC) compartments of a single photosynthetic cell. In this study, immunolocalization and in situ hybridization were used to examine the expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and key C4 photosynthetic genes, phosphoenolpyruvate carboxylase (PEPC), pyruvate, orthophosphate dikinase (PPDK) and NAD-malic enzyme (NAD-ME) during leaf development of B. sinuspersici. While polypeptides of Rubisco large subunit (LSU) were confined in the central compartment of the cell in the early stages of leaf development, its transcripts were expressed in both central and peripheral compartments. In mature leaves, Rubisco LSU proteins and transcripts were restricted to the CCC. In the longitudinal section of developing leaves, the expression of Rubisco LSU mRNA demonstrated the C3-C4 transition in the basipetal direction with transcripts specifically present in CCC at the leaf apex and found in both compartments toward the leaf base. Nuclear encoded transcripts such as PEPC, PPDK, NAD-ME and Rubisco small subunit were expressed in the cytoplasm of both compartments. PEPC and PPDK polypeptides appeared to be preferentially expressed in the peripheral cytoplasm and chloroplasts respectively. These results indicate that the regulation of expression of Rubisco and enzymes of C4 pathway during leaf development in the single-cell C4 species is complex and could involve several regulatory levels.

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P-134 Effect of DDB1A overexpression on DET1genetics and biochemistry Yu Zhang and Dana F. Schroeder Dept of Biological Sciences, University of Manitoba, Winnipeg, MN, Canada, R3T 2N2, Light is an important regulator of Arabidopsis growth. Dark-grown wildtype Arabidopsis seedlings exhibit elongated hypocotyls and small closed cotyledons, whereas light-grown seedlings develop photomorphogenically, exhibiting short hypocotyls and expanded green cotyledons. De-Etiolated 1 (DET1) is an important negative regulator of Arabidopsis photomorphogenesis. In loss-of-function DET1 mutants, dark-grown seedlings look photomorphogenic: they have short hypocotyls and open cotyledons. Transformation of det1 mutants with epitope-tagged DET1 can partially rescue the det1 mutant phenotype. UV-Damaged DNA Binding protein 1 (DDB1) is a component of the 350 kD DET1 complex in plant cells. DDB1A, one of two DDB1 genes in the Arabidopsis genome, has been found to genetically interact with DET1. To further study the biochemical and genetic interaction between DET1 and DDB1A, we generated Arabidopsis lines with overexpressed DDB1A-3HA in wildtype, det1, and Myc-DET1 and GFP-DET1 rescued genetic backgrounds. While overexpression of DDB1A-3HA did not result in significant phenotypic changes in wildtype background, it enhances det1 adult rosette width and flowering time phenotypes. Combination of DDB1A-3HA and Myc-DET1 overexpression resulted in decreased rescue of dark- and light-grown hypocotyls, light-grown anthocyanin and chlorophyll, adult height and stem number phenotypes. This result is consistent with the decreased levels of Myc-DET1 detected in the double overexpressor in dark- and light-grown seedlings as well as adults. Interestingly, the GFP-DET1 DDB1A-3HA double overexpressor exhibits increased rescue of dark hypocotyl and light chlorophyll phenotypes relative to GFP-DET1 alone, despite the fact that GFP-DET1 also decreases in this background. Variation in complex formation may account for this difference. In addition, increased DET1 results in DDB1A-3HA decrease. Overall, DDB1A-3HA overexpression affects phenotypes in different DET1 backgrounds and particularly reduces levels of epitope-tagged DET1 and modulates rescue of det1 mutants by the DET1-DDB1A complex. P-135 Responses of Two Contrasting Oat Cultivars to Water and Nitrogen Stresses BP Zhao 1,2, BL Ma2, and YG Hu1 1College of Agronomy and Biotechnology, China Agricultural University, No.2 Yuanmingyuan West Road, Haidian District , Beijing, China, 100094; 2ECORC, Agriculture and Agri-Food Canada, 960 Carling Ave, Ottawa, ON, Canada, K1A 0C6 zhaobpcau@hotmail.com Oat (Avena sativa L.) is a widely grown crop to be used for food and feed because of its high crude protein and low fiber. Water and nitrogen are the two most important factors which tremendously influence the growth and yield formation in oat production. A pot sand-culture study with two contrasting oat cultivars grown under three water regimes with four nitrogen (N) levels was conducted to determine the effect of water and N stresses on leaf

chlorophyll content (SPAD readings), photosynthetic rate (A), transpiration rate, stomata conductance (gs) , leaf water potential and biomass yield. The cultivars include: “Shadow”, the naked cultivar and “Bia”, the conventional hulled cultivar. The water regimes were: W1, >90% of full watering; W2, 60% of full watering; and W3, 30% of full watering. Nitrogen fertilizer levels included 25, 75, 150 and 250 kg N ha-1. The results showed that on average, the naked cultivar Shadow produced greater dry matter in shoot (9.6% more) and root (14.6% more) than the hulled Bia cultivar. However, at W3 (the most severe water stress treatment), both cultivars produced similar biomass yield. At heading, photosynthetic rate (A) of both cultivars was similar under water limiting conditions, but was 11.4% higher for Shadow than for Bia under non-water limiting conditions. Leaf chlorophyll content and stomata conductance (gs) of Shadow were also higher than those of Bia (P<0.05). Leaf chlorophyll content of both cultivars was consistently reduced by N stress, but not by water stress. On the contrary, leaf water potential increased with water stress, irrespective of N stress. Our data showed that, WUE leaf and WUE plant responded differently under water deficient conditions, with higher WUE leaf but lower WUE plant under the same conditions, indicating that caution must be taken when choosing biological traits as an indicator for improving oat genotypes with potential tolerance to drought and N stresses. P-136 High quality polyunsaturated fatty acids for cosmetics from arctic macroalgae Virginie Treyvaud-Amiguet1, N El Mehdi2, Y Boumghar2, M Allard3, G Rocheford3, JT Arnason1 1Dept of Biology, University of Ottawa, ON; 2 Centre of Chemical Process Studies of Québec (CÉPROCQ), Montréal, QC; 3 Nunavik Biosciences, Montréal , QC, Canada vtreyv@gmail.com The objective of this study was to develop natural health products from arctic natural resources and thus to create employment opportunities for Inuit communities. A mixture of brown macroalgae, Fucus distichus and F. vesiculosus, collected in collaboration with local Inuit (Ungava Bay, Nunavik), was extracted with hexane to obtain a crude extract containing fatty acids. The hexane extract was further purified to remove dark green pigments until a pale brownish yellow oil was obtained. Fatty acid analysis performed by gas chromatography showed a high content in polyunsaturated fatty acids with omega-6 such as linoleic acid and arachidonic acid, as well as omega-3 such as eicosapentaenoic acid, alpha-linolenic acid and stearidonic acid. This algal oil is not only rich in fatty acids with beneficial properties for the skin, but physico-chemical characteristics confirmed its promising cosmetic value. Analysis of polychlorinated biphenyl (PCBs) residue (< 0.01 ppm) showed that this oil has very low conta-minants.

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P-137 Dynamics of mycorrhizal symbiosis & heavy metal phytoremediation: Getting to the roots of metal-stress tolerance P Audet and Christiane Charest Dép de biologie, Université d’Ottawa, 30, rue Marie-Curie, Ottawa, ON, Canada, K1N 6N5 ccharest@uottawa.ca Increasing environmental pollutants, such as heavy metals (HM), pose a significant threat to ecosystems and human health. In this regard, plants are used to remove pollutants from contaminated environments through a phytor-emediation process. The arbuscular mycorrhizal (AM) symbiosis - an association between the roots of most herbaceous plants and the Glomeromycota fungi - is recognized for benefiting host plants subjected to stress factors, including soil-HM toxicity. Extending from this knowledge, our study investigates the roles of AM symbiosis in HM phytoremediation in the context of plant-HM uptake and relative plant growth. Using statistical meta-analytical modeling, we have determined that the AM fungi provide (1) an increased HM phytoextraction via ‘Enhanced Uptake’ at low soil-HM levels, and (2) a reduced HM bioavailability via ‘Metal-Binding’ at high soil-HM levels then resulting in increased plant biomass. By integrating these overall phenomena, termed the ‘Dynamic Mycorrhizal Uptake’ model, we propose that AM fungi enhance plant-HM tolerance via stress-avoidance by buffering toxic HM edaphic conditions. From this perspective, we deem that the AM fungi are key components of plant stress-tolerance systems and beneficial in remediation processes. P-138 Characterization of the biosynthesis and transport of steviol glycosides in Stevia rebaudiana Patrick Telmer, A Richman, R Chapman, and J Brandle telmerp@agr.gc.ca The Paraguayan herb Stevia rebaudiana produces at least eight of glycosylated diterpenes, the steviol glycosides, which have significant commercial value as potent non-caloric sweeteners. This biosynthetic pathway is a target candidate for metabolic engineering of secondary metabolites, as it is both economically valuable and highly productive resulting in an accumulation which can be up to 20% of the dry weight of the leaf. The intense sweetness of Stevia leaves is attributable to the glycosides stevioside and rebaudioside A, which are up to 270 and 300 times sweeter than sucrose. The early phase of steviol glycoside biosynthesis shares a common pathway with giberellin biosynthesis as steviol is a tetracyclic diterpene derived from the same kaurenoid precursor as giberellic acid. The first true branch-point from the giberellin pathway towards the production of steviol glycosides is the hydroxylation of kaurenoic acid, an intermediate in the gibberellin biosynthetic pathway to produce the diterpene steviol, which is subsequently glycosylated by cytoplasmic glycosyltransferases. We have used EST profiling and heterologous expression in yeast to identify a novel ent-kaurenoic acid hydroxylase responsible for the production of steviol. The final phase of glycoside accumulation in Stevia is the sequestration of glycosylated steviol within the

central vacuole. Steviol glycosides are known to occur in the vacuole, but the mechanism by which they are trafficked into the vacuole is not understood. Here we also report evidence of an energy dependant transport process responsible for uptake of steviol glycosides into the central vacuole. P-139 Characterization of Arabidopsis thaliana cells in tissue culture A Duwyn, M Krol, A Ivanov, and NPA Huner Dept of Biology and The Biotron, University of Western Ontario, London, ON, Canada, N6A 5B7 mkrol@uwo.ca Generally, plant cells grown heterotrophically in tissue culture exhibit a white phenotype because of photosynthetic genes are repressed by sucrose. However, we observed that Arabidopsis thaliana cells grown in tissue culture with sucrose as the carbon source maintain a green phenotype. Arabidopsis tissue culture cells grown in the dark exhibited a comparable growth rate to those cells grown in the light. However, the dark grown cells were devoid of chlorophyll. Furthermore, growth rates were significantly higher in sucrose than either mannitol or sorbitol. Growth in the presence of mannitol and sorbitol also inhibited chlorophyll accumulation relative to growth in the presence of sucrose. Thus, even though Arabidopsis cells grown in tissue culture in the presence of sucrose are green, photosynthesis is not required for growth. Consequently, we examined the structure and composition of the photosynthetic apparatus of the green cells grown in tissue culture with that of wild type Arabidopsis leaves. Arabidopsis tissue culture cells exhibited the same complement of all photosynthetic pigments as well as comparable energy distribution between photosystem II (PSII) and PSI measured by 77K fluorescence emission spectra. However, xanthophyll cycle activity, measured as changes in epoxidation state (EPS), was correlated with exposure to high light in WT leaves but in green tissue culture cells. Although tissue culture cells exhibited an apparent decrease in the abundance of the PSII and PSI reaction centre polypeptides, the content of Rubisco was similar to that observed in leaves of WT Arabidopsis. We conclude that, although Arabidopsis cells grown in tissue culture are green, photosynthesis is not required for cell growth. Furthermore, our preliminary data indicate that the structure and function of the photosynthetic apparatus in the green tissue culture cells is unique relative to that of WT leaves of Arabidopsis thaliana.

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