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Biotechnology Objectives: Students will be able to: Describe benefits and risks associated with biotechnology Recognize common examples of transgenic plants Describe the role of agencies that regulate biotechnology Bt Crops History A Japanese biologist was investigating the cause of the sotto disease (sudden-collapse disease) that was killing large populations of silkworms. He determined the bacterium Bacillus thuringiensis (Bt) as the cause of the disease in 1901. Ernst Berliner isolated a bacteria that had killed a Mediterranean flour moth in 1911, and rediscovered Bt. He named it Bacillus thuringiensis, after the German town Thuringia where the moth was found. Ishiwatari had named the bacterium Bacillus sotto in 1901 but the name was later ruled invalid. Berliner reported the existence of a crystal within Bt, but the activity of this crystal was not discovered until much later. Bt Crops History Farmers started to use Bt as a pesticide in 1920. At the time was used primarily to kill flour moths. More products containing Bt were marketed, but many of these products had limitations. Bt products such as sprays are rapidly washed away by rain, and degrade under the sun's UV rays. There were many insects that are not susceptible to any of the limited number of Bt strains known at the time. All the Bt strains known at the time were toxic to lepidopteran (moth) larvae only. There were also some insects that live within the plant or underground where the Bt sprays could not reach. Since synthetic insecticides were readily available and often very efficient in killing insects, Bt was not used widely. Bt Crops History In the 1980's use of Bt increased when insects became increasingly resistant to the synthetic insecticides and scientists and environmentalists became aware that the chemicals were harming the environment. Bt is organic and it affects specific insects and does not persist in the environment. Because of this, governments and private industries started to fund research on Bt. With the advancement in molecular biology, it soon became feasible to move the gene that encodes the toxic crystals into a plant. The first genetically engineered plant, corn, was registered with the EPA in 1995. Today, GM (genetically modified) crops including, potato and cotton are planted throughout the world. What is biotechnology? Use of biotechnical methods to modify the genetic material of living cells so they will produce new substances or perform new functions Moving or transferring genetic material between sources How are Bt crops an example of biotechnology? Advantages Decreased cost & labor Increased nutritional value of crops Increased shelf life Development of plants resistant to: Herbicides Insects Viruses Disadvantages Resistant Weeds Resistant Insects Increased food allergy Example- Increased Nutritional Value Biofortification Vitamin A deficiency is causes blindness and a weakened immune system Scientists have developed “Golden Rice” for areas of the world where Vitamin A is scarce Example- Increased Nutritional Value Soybean oil is high in linoleic acid which decreases the shelf life. To overcome this, soybean oil is hydrogenated which creates trans fatty acids Raising soybeans with a lower content of linoleic acid reduces the need to be hydrogenated Example- Increased Shelf Life Tomatoes with delayed ripening remain fresh longer Ethylene is a plant produced hormone that triggers maturity A gene can be inserted that reduces ethylene production Example- Resistant to Herbicides Round-up Ready corn can be directly sprayed with herbicides This prevents weeds from competing with resources that the corn needs and increases yield Example- Virus Resistant Between 20% & 80% of squash is destroyed by viruses Traditional plant breeding had not been effective at producing a virus resistant squash Biotechnology produced a squash that is resistant to the virus that kills squash while still on the vine. Example- Insect Resistant Colorado Potato Beetles defoliate potato plants and reduce their ability to preform photosynthesis The Bt protein is harmless to humans, but very detrimental to specific insects. It is placed in the genes of potatoes to control CPB. Prevents the application of insecticides How do we know that transgenic plants are safe? USDA, FDA & EPA each have roles in determining the safety of a new crop United States Department of Agriculture (USDA) Review data from field trials to determine if plant could become a pest or cause detrimental effects to the environment Approval must be gained for growth & transportation of genetically engineered plants Federal Drug Administration (FDA) FDA is responsible for the safety of all foods and animal feeds Developers must provide research data to the FDA prior to the release of a product Test new products for allergenicity Preventing Allergens Watch: https://www.youtube.com/watch?v=nVF7-iA1Q44 Answer the questions on your listening guide Environmental Protection Agency (EPA) Evaluates the safety of transgenic plants containing pesticidal proteins Considers the following factors: Risks to humans Risks to non-target organisms and the environment Gene flow potential I Insect resistance management plans Comparison of new proteins to known toxins and allergens Toxicity testing on birds, fish, earthworms, insects such as bees, ladybird beetles, and lacewings Toxicity testing on insects related to target insect pests Length of time required for the new proteins to degrade in the environment Regulatory Timeline Deregulation of bioengineered plants takes upwards of ten years to ensure safety to consumers and the environment Regulatory Timeline Activity Resources http://passel.unl.edu/pages/informationmodule.php?idinformationmodul e=991751218&topicorder=7&maxto=9&minto=1
