Transgenic technology Transgenic technology Breeding method Crop Improvement

Transgenic technology

Transgenic technology üBreeding method üCrop Improvement Problems in Agriculture 1. Quantity 2. Quality 3. Stress Environment 4. Public acceptance

Important Traits High crop yield n High nutritional quality n Abiotic stress tolerance n Pest resistance n Adaptation to inter-cropping n Nitrogen Fixation Insensitivity to photo-period n Elimination of toxic compounds n

Biotech goes global

Wide range of crops 16 Field Crops 14 Vegetables 16 Fruits 11 other crops Alfalfa Barley Canola Cassava Clover Cotton Flax Maize Rice Safflower Sorghum Soybean Sugar Beet Sugar Cane Sunflower Wheat Broccoli Cabbage Carrot Cauliflower Cucumber Eggplant Lettuce Onion Pea/Bean Pepper Potato Spinach Squash Tomato Apple Banana Cantaloupe Cherry Citrus Coconut Grape Kiwi Mango Melon Papaya Pineapple Plum Raspberry Strawberry Watermelon Chicory Cocoa Coffee Garlic Lupins Mustard Oil Palm Oilseed Poppy Olive Peanut Tobacco 57 fruits, vegetables, field crops and other plants – ranging from lab trials to commercial production

Field Crops by Country

The big five successful traits ü Herbicide Resistance ü Insect Resistance ü Virus Resistance ü Delayed Fruit Ripening Hot Issue 1. Genetically Modified Food 2. Golden Rice 3. Molecular Farming

Roundup Ready™ Soybeans A problem in agriculture is the reduced growth of crops imposed by the presence of unwanted weeds. Herbicides such as Roundup. TM and Liberty Link. TM are able to kill a wide range of weeds and have the advantage of breaking down easily. Development of herbicide resistant crops allows the elimination of surrounding weeds without harm to the crops.

Herbicide Resistance a) Glyphosate Resistance i. Glyphosate = “Roundup”, “Tumbleweed” = Systemic herbicide ii. Marketed under the name Roundup, glyphosate inhibits the enzyme EPSPS (S-enolpyruvlshikimate-3 phosphate – involved in chloroplast amino acid synthesis), makes aromatic amino acids. iii. The gene encoding EPSPS has been transferred from glyphosate-resistant E. coli into plants, allowing plants to be resistant. Glufosinate Resistance i. Glufosinate (the active ingredient being phosphinothricin) mimics the structure of the amino acid glutamine, which blocks the enzyme glutamate synthase. ii. Plants receive a gene from the bacterium Streptomyces that produce a protein that inactivates the herbicide.

Herbicide Resistance c) Bromoxynil Resistance i. A gene encoding the enzyme bromoxynil nitrilase (BXN) is transferred from Klebsiella pneumoniae bacteria to plants. ii. Nitrilase inactivates the Bromoxynil before it kills the plant. d) Sulfonylurea. i. Kills plants by blocking an enzyme needed for synthesis of the amino acids valine, leucine, and isoleucine. ii. Resistance generated by mutating a gene in tobacco plants, and transferring the mutated gene into crop plants.

Insect Resistance Various insect resistant crops have been produced. Most of these make use of the Cry gene in the bacteria Bacillus thuringiensis (Bt); this gene directs the production of a protein that causes paralysis and death to many insects. Corn hybrid with a Bt gene Corn hybrid susceptible to European corn borer

Insect resistance n Anti-Insect Strategy - Insecticides a) Toxic crystal protein from Bacillus thuringensis Toxic crystals found during sporulation n Alkaline protein degrades gut wall of lepidopteran larvae • Corn borer catepillars • Cotton bollworm catepillars • Tobacco hornworm catepillars • Gypsy moth larvae n Sprayed onto plants – but will wash off n The Bt toxin isolated from Bacillus thuringiensis has been used in plants. The gene has been placed in corn, cotton,

Insect resistance b) Plant protease inhibitors have been explored since the 1990 s: i. Naturally produced by plants, are produced in response to wounding. ii. They inhibit insect digestive enzymes after insects ingest them, causing starvation. iii. Tobacco, potato, and peas have been engineered to resist insects such as weevils that damage crops while they are in storage iv. Results have not been as promising as with Bt toxin, because it is believed that insects evolved resistance to protease inhibitors.

Virus Resistant Crops Papaya infected with the papaya ringspot virus Virus resistance gene introduced The Freedom II squash has a modified coat protein that confer resistance to zucchini yellows mosaic virus and watermelon mosaic virus II. Scientists are now trying to develop crops with as many as five virus resistance genes

Virus resistance a) Chemicals are used to control the insect vectors of viruses, but controlling the disease itself is difficult because the disease spreads quickly. b) Plants may be engineered with genes for resistance to viruses, bacteria, and fungi. c) Virus-resistant plants have a viral protein coat gene that is overproduced, preventing the virus from reproducing in the host cell, because the plant shuts off the virus’ protein coat gene in response to the overproduction. d) Coat protein genes are involved in resistance to diseases such as cucumber mosaic virus, tobacco rattle virus, and potato virus X.

Virus resistance e)Resistance genes for diseases such as fungal rust disease and tobacco mosaic virus have been isolated from plants and may be transferred to crop plants. f) Yellow Squash and Zucchini Seeds are available that are resistant to watermelon mottle virus, zucchini yellow mosaic virus, and cucumber mosaic virus. g) Potato. a) Monsanto developed potatoes resistant to potato leaf roll virus and potato virus X, which also contained a Bt toxin gene as a pesticide. b) hain restaurants do not use genetically engineered potatoes due to public pressures. h) Papaya Varieties resistant to papaya ring spot virus have been

First biotech plant product – Flav’r Sav’r tomato “Rot-Resistant Tomato” Anti-sense gene complementary to polygalacturonase (PG) PG = pectinase accelerates plant decay/rotting ü ü

Delayed Fruit Ripening a) Allow for crops, such as tomatoes, to have a higher shelf life. b) Tomatoes generally ripen and become soft during shipment to a store. c) Tomatoes are usually picked and sprayed with the plant hormone ethylene to induce ripening, although this does not improve taste d) Tomatoes have been engineered to produce less ethylene so they can develop more taste before ripening, and shipment to markets.

Plant Biotechnology Revolution: Genetically Engineered Foods. ü Foods that contain an added gene sequence ü Foods that have a deleted gene sequence ü Animal products from animals fed GM feed ü Products produced by GM organisms

Plant Biotechnology Revolution: Genetically Engineered Foods. 1. More than 60% of processed foods in the United States contain ingredients from genetically engineered organisms. 2. 12 different genetically engineered plants have been approved in the United States, with many variations of each plant, some approved and some not. 3. Soybeans. a) Soybean has been modified to be resistant to broadspectrum herbicides. b) Scientists in 2003 removed an antigen from soybean called P 34 that can cause a severe allergic response. 4. Corn a) Bt insect resistance is the most common use of

Plant Biotechnology Revolution: Genetically Engineered Foods 4. Corn a) Bt insect resistance is the most common use of engineered corn, but herbicide resistance is also a desired trait. b) Products include corn oil, corn syrup, corn flour, baking powder, and alcohol. c) By 2002 about 32% of field corn in the United States was engineered. 5. Canola. a) More than 60% of the crop in 2002 was genetically engineered; it is found in many processed foods, and is also a common cooking oil. 6. Cotton. a) More than 71% of the cotton crop in 2002 was engineered. b) Engineered cottonseed oil is found in pastries, snack foods, fried foods, and peanut butter. 7. Other Crops Other engineered plants include papaya, rice, tomato, sugar beet, and red heart chicory.

Golden Rice Normal rice Transgenic technology produced a type of rice that accumulates beta-carotene in rice grains. Once inside the body, beta-carotene is converted to vitamin A. “Normal” rice “Golden” rice

Plant Biotechnology Revolution: Nutritionally Enhanced Plants Golden Rice 1. More than one third of the world’s population relies on rice as a food staple, so rice is an attractive target for enhancement. 2. Golden Rice was genetically engineered to produce high levels of beta-carotene, which is a precursor to vitamin A. Vitamin A is needed for proper eyesight. 3. Biotechnology company Syngenta, who owns the rights to Golden Rice, is exploring commercial opportunities in the United States and Japan. Monsanto will provide licenses to Golden Rice technology royalty-free. 4. Other enhanced crops include iron-enriched rice and tomatoes with three times the normal amount of betacarotene

Pharmaceutical Production in Plants Genetically modified plants have been used as “bioreactors” to produce therapeutic proteins for more than a decade. A recent contribution by transgenic plants is the generation of edible vaccines. Edible vaccines are vaccines produced in plants that can be administered directly through the ingestion of plant materials containing the vaccine. Eating the plant would then confer Edible vaccines immunity against produced diseases. by transgenic plants are attractive for many reasons. The cost associated with the production of the vaccine is low, especially since the vaccine can be ingested directly, and vaccine production can be rapidly up scaled should the need arises. Edible vaccine is likely to reach more individuals The first human clinical trial took place in in developing countries. 1997. Vaccine against the toxin from the bacteria E. coli was produced in potato. Ingestion of this transgenic potato resulted in satisfactory vaccinations and no adverse effects.

Plant Biotechnology Revolution: Molecular Farming 1. A new field where plants and animals are genetically engineered to produce important pharmaceuticals, vaccines, and other valuable compounds. 2. Plants may possibly be used as bioreactors to mass -produce chemicals that can accumulate within the cells until they are harvested. 3. Soybeans have been used to produce monoclonal antibodies with therapeutic value for the treatment of colon cancer. Drugs can also be produced in rice, corn, and tobacco plants 4. Plants have been engineered to produce human antibodies against HIV and Epicyte Pharmaceuticals has begun clinical trials with herpes antibodies

Plant Biotechnology Revolution: Molecular Farming 5. Edible Vaccines a) People in developing countries have limited access to many vaccines. b) Making plants that produce vaccines may be useful for places where refrigeration is limited. c) Potatoes have been studied using a portion of the E. coli enterotoxin in mice and humans. d) Other candidates for edible vaccines include banana and tomato, and alfalfa, corn, and wheat are possible candidates for use in livestock. e) Edible vaccines may lead to the eradication of diseases such as hepatitis B and polio.

One focus of current Edible vaccine Vaccines effort is on hepatitis B, a virus responsible for causing chromic liver disease. Transgenic tobacco and potatoes were engineered to express hepatitis B virus vaccine. During the past two years, vaccines against a E. coli toxin, the respiratory syncytial virus, measles virus, and the Norwalk virus have been successfully expressed in plants and delivered orally. These studies have supported the potential of edible vaccines as preventive agents many diseases. There is hope to of produce edible vaccines in bananas, which are grown extensively throughout the developing world.

Plant Biotechnology Revolution: Biopolymers and Plants a) Plant seeds may be a potential source for plastics that could be produced and easily extracted. b) A type of PHA (polyhydroxylalkanoate) polymer called “poly-beta-hydroxybutyrate”, or PHB, is produced in Arabidopsis, or mustard plant. c) PHB can be made in canola seeds by the transfer of three genes from the bacterium Alicaligenes eutrophus, which codes for enzymes in the PHB synthesis pathway. d) Monsanto produces a polymer called PHBV through Alicaligenes fermentation, which is sold under the name Biopol.

Areas of ongoing debate Environment n Human Health n Food security Socio-economic concerns n n

Environment n n Anti-GM Loss of biodiversity Cross-pollination Emergence of superweeds and superbugs Potential increase in use of herbicides *Opinions are generalized, and not all opponents or proponents may hold all of these views. n n n Pro-GM Need to increase yields to feed growing population Possibility of reducing need for pesticides, fertilizers Grow more food on same amount of land

Human Health Anti-GM n n n Fear of unknown allergens Spread of anti-biotic resistance Inadequate regulation of new products Pro-GM n n Greater regulations than other foods Potential benefits to nutrition • golden rice • enhanced protein content in corn • soybean oil with less saturated fat

Food Security n n n Anti-GM Need redistribution, not just more Farmers will not be able to afford expensive seed Developing countries should not have to eat the food others reject n n Pro-GM Modified seeds will allow farmers to grow more to feed their family and to sell, reducing the need for food aid Public-private cooperation can transfer technology

Socio-economic concerns n n n Corporations benefit, not those in need Products needed in developing countries are not being developed because the market is not profitable It is wrong to patent life n n Patents needed because new strains are intellectual property Publicly funded research can benefit the public good