lec7 gmo09-1 - Plant Examples of GMO’s Plant Examples of...

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Unformatted text preview: Plant Examples of GMO’s Plant Examples of GMO’s Herbicide tolerance­ potential to decrease spraying of herbicides Pesticide resistance­ decrease spraying of pesticides Stress Tolerance­ resistance to environmental stresses Altering quality of food­ nutrition, aesthretic quality Nutrition Nutrition Engineering crops for increased nutrition Golden Rice – engineered for increased beta­ carotene­ converted in body to vitamin A Engineered beans to alter carbohydrate level and increased protein levels Nutrigenomics­ Understanding nutrition at molecular/ genetic level Insect Resistance Insect Resistance Bt crops­ Corn, cotton, potatoes Bacillus thuringiensis­ bacterium that infects insects­ Protein extracts developed into organic pesticides­ 95% of the organic pesticide market in the late 1980’s Plants modified to produce the Bt protein in leaves, available since 1996 Insect Resistance Insect Resistance Lectins­ Insecticidal proteins produced by some plants. A lectin from a wildflower species has been inserted into potatoes to deter potato beetles Avidin­ a protein from egg whites inserted into corn to stop storage pests Virus Resistance Virus Resistance As in most animals, viruses are hard to treat in plants Viruses are genetic material in a protein coat which insets itself into cells Papaya Ringspot Virus­ Gene for Protein coat inserted into papayas­ conferred resistance to the virus Potentially useful for generating virus resistance in other plants as well. Some plants have natural resistance to insects, fungi, and viruses Efforts are being made to transfer resistance from these plants to valuable crop plants Herbicide Tolerance Herbicide Tolerance Generate Herbicide Tolerant crop plants to allow the use of broad spectrum herbicides on crop fields Varieties are often developed by Chemical companies and marketed with the herbicide Roundup Tolerance Roundup Tolerance Roundup (Glyphosate)­ A broad spectrum herbicide­ disrupts biochemical pathway in the plant which produces a plant­specific essential amino acid. Breaks down quickly in soil, leaving no residue Roundup­ ready Soybean, canola, cotton, corn, grass seed, wheat are all available Herbicide Tolerance Herbicide Tolerance Second generation Herbicide/crop combos are becoming available by other chemical companies Often crops are engineered to produce terminator seeds­ seeds produced by engineered plants are not viable. Grower needs to buy new seed each year. Stress Tolerance Stress Tolerance Salt Tolerance in Rice­ Rice varieties have been engineered to survive in high salt areas. Allow for growth in brackish water Cold/ freezing tolerance­ plants have been engineered with “antifreeze” proteins from Flounder to confer freezing tolerance­ done in strawberries Arguments against GMO’s Arguments against GMO’s Health and Safety issues Long term Problems­ escape of genes into wild populations Ethical Issues Are they necessary? Health Issues related to Techniques Health Issues related to Techniques Use of Antibiotic Resistance genes as markers Random insertion into genome­ waking up “sleeper genes”, silencing active genes Will gene be stable in the long term Potential Allergens­ is the inserted gene safe as a food product? Example­ Brazil nut gene inserted into Soybeans in late 1990’s to elevate amino acid content was an allergen GMO’s andAgriculture­ Potential GMO’s and Agriculture­ Potential Issues Some evidence for this, transgenes have been found in wild corn Escape of genes into wild populations ­ Gene Flow Build up of Resistant Weeds or Build up of Resistant Weeds or Insects Spraying with a single pesticide selects for resistant weeds that have less competition­ becoming an issue with Roundup­ Ready crops Increased resistant insects also a problem­ can be dealt with by planting some non­resistant crops Other issues­ Agriculture Other issues­ Agriculture Potential risks to non target species­ could plant producing pesticide harm beneficial species? Loss of diversity­ potential for invasive species which out­compete native species Dangers of monoculture­ growing one variety which could be wiped out if novel pathogen arrives­ lack of genetic diversity Are terminator products fair? Forcing growers to purchase new seeds every year. Intellectual property rights can slow basic research­ no longer an open exchange of information in the scientific community Ethical Issues Ethical Issues Do we have right to blur the distinction between species? Dangers of genetic profiling Should we have the right to modify humans, potential for exploitation? Is it ethical to breed animals specifically for xenotransplantation? Is it necessary? While modified organisms may provide benefits, are they really necessary? Arguments in favor of GMO’s Arguments in favor of GMO’s Exciting possibilities­ cure genetic diseases, feed the world, which can improve quality of life Techniques are basically safe­ accelerated traditional breeding Ethical Issues can be dealt with With proper testing safe GMO’s can be produced Regulation of GMO’s Regulation of GMO’s In the USA, GMO’s regulated by the Food and Drug Administration (FDA), the Environmental Protection Agency (EPA), and the Department of Agriculture (USDA). FDA FDA FDA determines the safety of foods and food ingredients. Although the FDA consults with food developers about their data on the safety and nutrition of GMOs, submission of such data to the FDA is voluntary. A GMO judged to be "substantially equivalent" to the existing crop, except for its transgene, does not require rigorous safety testing. EPA EPA The EPA evaluates the effects of pest­ and herbicide­resistant GMOs on the environment. Plants containing pesticide genes are often labelled as pesticides USDA USDA The USDA checks the safety of growing GMOs to learn, for example, whether the transferred genes are stable and whether the GMO might become a pest. ...
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This note was uploaded on 01/10/2010 for the course BIOPL 2400 at Cornell University (Engineering School).

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