WHAT ARE TRANSGENIC PLANTS? • Modification of DNA using genetic engineering techniques. • Aim is to introduce a new trait to the plant . • The inserted sequence is known as the transgene. • The purpose of inserting a combination of genes in a plant, so as to make it as useful and productive as possible. • Examples in food crops include resistance to certain pests, diseases, or environmental conditions, reduction of spoilage, or resistance to chemical treatments (e.g. resistance to a herbicide), or improving the nutrient profile of the crop.
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WHAT ARE TRANSGENIC PLANTS?• Modification of DNA using genetic engineering techniques.• Aim is to introduce a new trait to the plant .• The inserted sequence is known as the transgene.• The purpose of inserting a combination of genes in a plant, so as to
make it as useful and productive as possible. • Examples in food crops include resistance to certain pests,
diseases, or environmental conditions, reduction of spoilage, or resistance to chemical treatments (e.g. resistance to a herbicide), or improving the nutrient profile of the crop.
• Examples in non-food crops include production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation.
WHY MAKE TRANSGENIC PLANTS?
• Desirable genes may provide features such as higher yield or improved quality, pest or disease resistance, or tolerance to heat, cold and drought.
• Transgenic technology enables plant breeders to bring together in one plant useful genes from a wide range of living sources.
• Generate more useful and productive crop varieties containing new combinations of genes.
• Expands the possibilities beyond the limitations imposed by traditional cross-pollination and selection techniques.
HISTORY• The first genetically modified crop plant was produced in 1982, an
antibiotic-resistant tobacco plant.
• In 1987, Plant Genetic Systems ,founded by Marc Van Montagu and Jeff Schell, was the first company to genetically engineer insect-resistant (tobacco) plants by incorporating genes that produced insecticidal proteins from Bacillus thuringiensis (Bt).
• The first genetically modified crop approved for sale in the U.S, in 1994, was the FlavrSavr tomato as it had a longer shelf life.
• In 1994, the European Union approved tobacco engineered to be resistant to the herbicide bromoxynil, making it the first commercially genetically engineered crop marketed in Europe.
HISTORY• In 1995, Bt Potato was approved by the US Environmental
Protection Agency, making it the country's first pesticide producing crop.
• In 1995 canola with modified oil composition (Calgene), (Calgene), Bt cotton (Monsanto), glyphosate-resistant soybeans (Monsanto), virus-resistant squash (Asgrow), and additional delayed ripening tomatoes (DNAP, Zeneca/Peto, and Monsanto) were approved.
• In 2000, Vitamin A-enriched golden rice, was the first food with increased nutrient value.
MOST COMMONLY USED GENETIC ENGINEERING TECHNIQUES
• Microprojectiles (biolistics or particle gun) for gene transfer
• NutritionSome GM soybeans offer improved oil profiles for processing or healthier eating. Camelina sativa has been modified to produce plants that accumulate high levels of oils similar to fish oils.
• Vitamin enrichment Golden rice, developed by the International Rice Research Institute (IRRI), provides greater amounts of Vitamin A targeted at reducing Vitamin A deficiency.
• Toxin reductionA genetically modified cassava under development offers lower cyanogen glucosides and enhanced protein and other nutrients (called Bio Cassava).
• Stress resistanceIn 2011, Monsanto's Drought Gard maize became the first drought-resistant GM crop to receive US marketing approval.
• Herbicides(i) Glyphosate-The transgenic petunia plants resistant to
glyphosate(active ingredient of Roundup herbicide) were developed by transfer of a gene for EPSPS(5-enol-pyruvyl-shikimat-3-phosphate synthase), that overproduces this enzyme.
(ii) Bromoxynil-Tobacco plants have been engineered to be resistant to the herbicide bromoxynil.
(iii) 2-4D- The transgenic maize and soyabean resistant to 2-4D were developed by inserting a bacterial aryloxyalkanoate dioxygenase gene, aad1 makes the corn resistant to 2,4D.
• Pest resistance(i) Insects-The Bt toxin produced by Bacillus thuringiensis has been
isolated and used for Agrobacterium Ti plasmid mediated transformation of tobacco, cotton and tomato plants.
(ii) Virus- 80% of Hawaiian papaya plants were genetically modified by incorporating Pseudorabies virus (PRV) DNA.
ADVANTAGES• For the producers of the new varieties- A high efficiency in plants is obtained.
• For farmers-Process of pests destroying is simplified, therefore less damage.-Production output is increasing as well as the profits of transgenic cultures, even the obtaining cost of the GMO is rather high.
• For industry- As in the case of modified starch, low lignin content wood (in this case paper manufacturing is less pollutant), human protein production(for therapeutic aim)
• For consumers- More nutritious-Fruits and vegetables with delayed maturation can easily be stored, with minimum losses.-In future, transgenic plants contain higher content of vitamins, minerals, essential amino acids by using the vaccine plants, the rice enriched in pro-vitamin A etc.
• For the environment and human future-Imply lower pollution-Higher agricultural productions
GLOBAL STATUS OF BIOTECH CROPS IN YEAR 2014
EXAMPLES OF TRANSGENIC PLANTS
Transgenic potato The high productivity, nutritional quality and amenability to
genetic manipulation makes potato a choice crop for developing transgenic plants on diverse parameters.
Late blight, bacterial wilt, viruses, the potato tuber moth and sensitivity to high temperatures are the major production constraints best addressed by transgenic potatoes.
The alteration of the carbohydrate metabolism for the industrial production of cyclodextrin, fructan, and quality starch would overcome certain utilization constraints. The production of vaccines for major livestock diseases such as Rinderpest and Foot and Mouth Disease of cattle, and New Castle disease of poultry are new utilization possibilities.
Potato Annexin- Drought Tolerance & Light stress
• Annexins are a family of calcium- and membrane-binding proteins that are important for plant tolerance to adverse environmental conditions.
• Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance.
• Consequently, these plants were able to maintain effective photosynthesis during drought, which resulted in greater productivity than WT plants despite water scarcity.
• They are more tolerant to water deficit in the root zone, preserve more water in green tissues, maintain chloroplast functions, and have higher accumulation of chlorophyll b and xanthophylls than wild type (WT).
• Enhanced drought tolerance in transgenic potato confers greater tolerance to high light stresses, stomatal closure, and diminished CO2 supply.
Insecticide sweet corn
• Scientists have genetically modified sweet corn so that it produces a poison which kills harmful insects. This means the farmer no longer needs to fight insects with insecticides. The genetically modified corn is called Bt-corn, because the insect-killing gene in the plant comes from the bacteria Bacillus thuringiensis.
Insecticide sweet corn
Advantages
• The farmer no longer has to use insecticide to kill insects, so the surrounding environment is no longer exposed to large amounts of harmful insecticide. The farmer no longer needs to walk around with a drum of toxic spray wearing a mask and protective clothing
Disadvantages• This type of genetically modified corn will poison the insects
over a longer period than the farmer who would spray the crops once or twice. In this way the insects can become accustomed (or resistant) to the poison. If that happens both crop spraying and the use of genetically modified Bt-corn become ineffective.
• A variety of insects are at risk of being killed. It might be predatory insects that eat the harmful ones or, perhaps attractive insects such as butterflies. In the USA, where Bt-corn is used a great deal there is much debate over the harmful effects of Bt-corn on the beautiful Monarch butterfly.
• Cotton and potatoes are other examples of plants that scientists have , genetically modified to produce insecticide.
Golden rice• Golden rice is genetically modified rice that now contains
a large amount of A-vitamins. Or more correctly, the rice contains the elementbeta-carotene which is converted in the body into Vitamin-A. So when you eat golden rice, you get more vitamin A.
• Beta-carotene gives carrots their orange colour and is the reason why genetically modified rice is golden. For the golden rice to make beta-carotene three new genes are implanted: two from daffodils and the third from a bacterium.
Golden rice
Advantages
• The rice can be considered a particular advantage to poor people in underdeveloped countries. They eat only an extremely limited diet lacking in the essential bodily vitamins. The consequences of this restricted diet causes many people to die or become blind. This is particularly true in areas of Asia, where most of the population live on rice from morning to evening.
Disadvantages
• Critics fear that poor people in underdeveloped countries are becoming too dependent on the rich western world. Usually, it is the large private companies in the West that have the means to develop genetically modified plants. By making the plants sterile these large companies can prevent farmers from growing plant-seed for the following year - forcing them to buy new rice from the companies.
• Some opposes of genetic modification see the "golden rice" as a method of making genetic engineering more widely accepted. Opponents fear that companies will go on to develop other genetically modified plants from which they can make a profit. A situation could develop where the large companies own the rights to all the good crops
Long-lasting tomatoes
• Long-lasting, genetically modified tomatoes came on to the market in 1994 and were the first genetically modified food available to consumers. The genetically modified tomato produces less of the substance that causes tomatoes to rot, so remains firm and fresh for a long time.
Long-lasting tomatoes
Advantages
• Because the GM tomatoes can remain fresh longer they can be allowed to ripen in the sun before picking - resulting in a better tasting tomato.
• GM tomatoes can tolerate a lengthier transport time. This means that market gardens can avoid picking tomatoes while they are green in order that they will tolerate the transport.
• The producers also have the advantage that all the tomatoes can be harvested simultaneously.
Disadvantages
• Scientists today can genetically modify tomatoes without inserting genes for antibiotic resistance. However the first genetically modified tomatoes contained genes that made them resistant toantibiotics. Doctors and vets use antibiotics to fight infections. These genes spread to animals and people, doctors would have difficulties fighting infectious diseases.
• Strawberries, pineapples, sweet peppers and bananas have all been genetically modified by scientists to remain fresh for longer.
DISADVANTAGES OF TRANSGENIC PLANTS
• Damage to human health• allergies• horizontal transfer and antibiotic resistance• eating foreign DNA• changed nutrient levels
• Damage to the natural environment• crop-to-weed gene flow• leakage of GM proteins into soil• reductions in pesticide spraying: are they real?
• Disruption of current practices of farming and food production in developed countries• crop-to-crop gene flow
• Disruption of traditional practices and economies in less developed countries.
• Lack of research on consequences of transgenic crops.
CURRENT SCENARIO• Commercially grown transgenic crops in developed countries include ‘Flavr Savr’ and ‘Endless Summer’
tomatoes, ‘High-lauric rapeseed (canola) and ‘Roundup Ready’ soyabean.
• More than 60 transgenic dicot plants including herbs, shrubs and trees and several monocots like maize, oat,
rice, wheat, etc. have been produced.
• Currently, India is importing both grain legumes and edible oils to meet people’s demand.
Some Transgenic crops approved by FDA (U.S.A.)PRODUCERS IMPROVED TRAITS CROP PLANTS
AgroEvo Weed control and Hybrid production
Canola
Calgene High laurate oil and Weed control
Canola
Cornell University Virus resistance Papaya
DuPont Weed control and Improved oil
Cotton and Sugarbeet
Monsanto Weed control, Insect resistance,
Insect control, Virus control
Canola, Corn, Soyabean, Cotton,
Tomato, Potato.
Major Indian Developments in Transgenic Research and application in Public sector
INSTITUTE CROP PLANT AIMS OF THE PROJECT
CCMB, Hyderabad Rice To generate Herbicide tolerance
Central Potato Research Institute, Shimla.
Potato To generate Insect resistance
University of Agricultural Science,
Bangalore.
Muskmelon To develop Edible vaccine.
Central Tobacco Research Institute,
Rajahmundry.
Tobacco To generate Insect resistance.
Madurai Kamraj University
Coffee To develop resistance to Fungal infections.
REALIZING THE POTENTIALAs BIOREACTORS (Molecular Farming) For manufacturing special chemicals and pharmaceutical compounds.
Transgenic material in the form of seeds or fruit can be easily stored and transported from one place to another without degradation or damage.
In successful trials, transgenic plants have been found to produce monoclonal antibodies, functional antibody fragment, proteins, vitamins and the polymer Polyhydroxybutyrate(PBH), which can be used to prepare biodegradable plastics.
• Nutritional quality:• Improving health of malnourished people in
poor countries.• Development of Golden Rice, rich in Vitamin A.• Work done in India on the introduction of amal
gene from Amaranthus into potato holds promise for enhancing nutritional value of low protein food.
• Therapeutic Proteins:• Used in the treatment and diagnosis of human
diseases.• 3 types/classes-
o Edible Vaccines-• Vaccines against infectious diseases of the
gastrointestinal tract have been produced in plants like potato and banana.
• A rabies virus coat glycoprotein gene has been expressed in tomato plants. Orally administered protein provided protective immunity in animals.
o Edible Antibodies-• Antibodies directed against dental caries,
cholera, malaria, influenza, and hepatitis B virus are known to be produced in transgenic plants.
• An anti cancer antibody has recently expressed in rice and wheat seed that recognizes cells of lung, breast and colon cancer and hence could be useful in both diagnosis and therapy in the future.
o Edible Interferons-• The Indian scientists at ICGEB, New Delhi
have successfully produced transgenic maize, tobacco, rice, etc. capable of producing interferon gamma (IFN-).
THE FUTUREThe enhanced production of GM crops to eliminate hunger, carries hidden costs in environment and health concerns.
More research is required to determine the true safety of these plants and to decide, whether they are safe for both the environment and for the human consumers.
In future, the transgenic crops will be used not only for improved agronomic traits, but also for traits involving food processing, pharmaceuticals and specialty chemicals.
• Transgenic rubber has also been produced and will be used for a variety of purposes.
• Thus, the future of these crops is bright and optimistic.
• The market of these crops is expected to reach the level of 10 billion US dollars in 2020.
• The public and farmers will have to respond to the changing scenario.
• Future generations of GM plants are intended to be suitable for harsh environments, and for enhancement of nutrient content, production of pharmaceutical agents and production of Bioenergy and Biofuels.
