Dean W. GabrielDean W. Gabriel

GM Citrus with Potential to Control Greening

Integrated Plant Genetics, Inc.Integrated Plant Genetics, Inc.AlachuaAlachua

andand

Plant Pathology DepartmentPlant Pathology DepartmentUniversity of Florida, GainesvilleUniversity of Florida, Gainesville

Strategies for greening disease control

o No practical resistance breeding. o Eradication impossible. o Chemical control of insects may require 25 sprays per year.

o Genetically modified (GM) citrus (add a resistance gene).

APHIS/PPQ intercepted the vector40 times in US ports between 1985-98.

APHIS/PPQ intercepted the vector40 times in US ports between 1985-98.

Citrus greening, likely trapped in dooryard citrus, nationwide.

6 year lag from psyllid establishment to greening diagnosis.

Canker bacteria

Greening bacteria

Why don't chemicals work on greening?

Nucleus

How to make a "GMO"

1. Start with DNA cloning vector.2. Add gene of interest + plant selection gene.3. Add cloned genes on vector to specialized bacterial pathogen.

4. Contact pathogen with target plant cell.5. The pathogen injects the cloned genes into the plant cell, and the

genes are guided to the nucleus by DNA vector.

1 2

1. In a test tube, construct a gene encoded on vector DNA.

2. Add the vector DNA to a specialized bacterial pathogen.

3. Contact wounded citrus with the pathogen; the vector DNA is injected by the pathogen into the plant cell.

--Essenberg & Richardson

Transformation process for GM Citrus

Transformation process for GM Citrus

Bacteria with clonedgenes applied to cut end of citrus stem section.Antibiotic selection applied.

Transformation process for GM Citrus Transformation process for GM Citrus

Greenhouse testing

Grafting onto rootstock

1 2

4 weeks --- 26% juvenile stem pieces survive; 1/2 of these are transformed

Mature Valencia & Hamlin regenerated

Juvenile grapefruit after grafting

May, 2008: Growth of transgenic citrus trees, each with 1 of 3 IPG DiseaseBlock genes.

Current status: GM citrus trees currently being evaluated by IPG. Technology (IP) is co-owned by UF.

Citrus has natural defenses

Transgenes that interfere with defense are more susceptible...

Citrus has natural defensesHarder to prove are transgenes that enhance defense... a negative result (determined by PCR). To date, negative.

IPG DiseaseBlock® added

Transgenic tobacco as proxy... to date negative

IPG DiseaseBlock® added

GMOs can be accepted in the U.S.

Transgenic and nontransgenic papaya in Hawaii. Work by: D. Gonsalves, Cornell U.; S. Ferreira and R. Manshardt, U.Hawaii; M. Fitch, USDA; J. Slightom, Pharmacia

Transgenic 'UH Rainbow' to be graded in a commercial packinghouse.

Adoption Rates: Principal GM Crops in US

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1996 1997 1998 1999 2000 2001 2002 2003 2004

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Soybean

Corn

Cotton

The Regulatory Process---Who's minding the Store?

NIH mandated IBC review USDA-APHIS facility review• USDA-APHIS field-release approval• USDA-APHIS shipping authority

approval• USDA-APHIS permission to

commercialize or non-regulatory status (public comment, 12-24 mo)

The Regulatory Process

• EPA experimental use permit (if > 10 acres)

• EPA determines if limits needed on % gene product (public comment, 24-30 mo.)

• EPA product registration (public comment)

• FDA review (public comment (12-18 mo.)Earliest time to market: 2015

Integrated Plant Genetics, Inc.

12085 Research DriveAlachua, Florida 32615 USA

http://www.ipgenetics.com

gabriel@ipgenetics.com

IPG Research Sponsored by:

Southern Gardens CitrusUSDA-APHISNSFFischer USAGoldsmith Plants