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Uwe Stolz NERL Postdoctoral Research Fellow Genomics Workshop, Chicago, IL April 29, 2005 Agricultural Biotechnology: Genomic Approaches to Monitoring the Effects of Genetically Modified Crops
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Agricultural Biotechnology: Genetically modified crops
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Current and Future GM Crop Traits 1.Insect Resistance (Plant Incorporated Protectants) – ex: BT corn & cotton 2.Herbicide Tolerance – ex: Glyphosate Resistant Corn & Soybeans (i.e. Roundup Ready) 3.“Value Added” Crops – ex: Golden Rice containing vitamin A 4.Stress Tolerance – ex: drought, salt resistant varieties 5.“Biopharming” – Production of drugs, chemicals on agricultural scales
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Major environmental and health concerns regarding GM crops Non-target effects Gene flow / Transgene Escape Insect Resistance Allergenicity
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Issues for Regional Monitoring Efforts Non-target Effects Species, Communities, Ecosystems Beneficial species, threatened / endangered species Gene Flow / Transgene Escape Crop to Crop, Crop to Wild Relative, Crop to distant relative Insect resistance genes, herbicide tolerance genes Future – vaccines, chemicals, drugs, etc.
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Non-target effects of GM corn 1.Bt corn and non-target effects: Yieldgard Corn 2.ORD/NERL research approach / rationale 3.Research progress 4.Monitoring Applications
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Agricultural Pesticides: UnintendedEnvironmentalImpact Intended and unintended effects Human Health Effects Effects Targeted Insect Pest
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80 million acres of corn planted per year (20% of total crop acreage) Western Corn Rootworm (WCR) is major pest of corn. Conventional insecticides applied to 14-18 million acres per year. WCR responsible for 1 out of 7 insecticide applications for all agricultural crops WCRdamage
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CRW will continue to be a problem… Infested acres of CRW expected to increase: 39 million acres by 2013 EPA identified 10 insecticides used in agriculture as the most toxic to birds - 3 currently used to control corn rootworm (carbofuran, phorate and methyl parathion). CRW have adapted to crop rotation with soybeans and have evolved resistance to several chemical insecticides
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Bt-corn NonBt-cornNonBt-corn Bt-corn reduces the need for conventional pesticides:
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The Evolution of Bt-Resistance is an Environmental Problem ??
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Current Research of ORD - NERL in Cincinnati Monitor resistance genes in pest populations -Identify resistance/tolerance genes -Develop molecular techniques for rapid and cost effective screening Monitor non-target species for effects of Bt exposure -Identify gene expression markers for Bt exposure in target pests -Develop assays to test for effects in related non- targets
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Complements ecological monitoring by adding another level of analysis and increases the amount of information that can be gathered about the status and health of species Advantages of Genetic Monitoring
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Non-Target-Monitoring What is a non-target species? How do we choose non-targets? Molecular genetics to monitor non-targets Gene Expression Benefits of molecular genetic techniques
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Non-Target Effects: The Agricultural Landscape ? ? ? Non-economic Economic
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Non-Targets Economic non-targets Non-target pests Beneficial predators Other beneficial Insects Non-Economic non-targets Threatened/endangered species Species of public concern Species whose primary habitat is not agricultural
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Gene Expression Detects exposure to pesticides/PIP Detects biologically meaningful exposure Detects non-acute effects Permits study of non-lab species Highly sensitive - ex: EDCs in streams
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Bt Corn WCR Gene Expression Changes DIET +ROOT +BT STD DIET 1 3 4 5 6 2 bt DIET +ROOT
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Results from QPCR for six clones identified through differential display.
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Once Gene Expression Markers Confirmed Non-target species can be monitored for exposure to PIPs and/or pesticides (QPCR, RT- PCR) Several closely related species can be monitored at the same time to detect ecosystem level patterns
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Proof of Concept Research We are examining ground beetle species across corn growing areas Examine several species communities Look at exposure to Bt corn -ELISA assays using beetle guts to check for presence of Bt toxin -Gene expression assays
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Gene Flow / Transgene Escape
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Contamination of food supply Creation of “super-weed” crops Transgene escape to native relatives via hybridization, creation of super- weeds Genetic pollution Major Issues of Transgene Escape / Gene Flow
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Use GM crops with few wild relatives (ex: Corn in the USA, Canada, Europe) Use GM crops with no weedy relatives (ex: Sorghum and Johnson Grass) Provide sufficient physical and physiological barriers to gene flow (ex: plant isolated patches, have appropriate borders, sterility) Monitor for the escape and movement of transgenes Keys to Prevention of Transgene Flow
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Case Study of EPA work on Transgene Flow Herbicide (Roundup) resistant bent grass Considered for turf management Improve golf courses
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CD = managed bentgrass field Sentinel plants = potted plants Resident = naturally occurring
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In addition to PCR, also used Elisa (checks for protein product of transgene) and used seedlings from sentinel plants to check for RoundUp resistance (phenotype of transgene).
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Ultimate Goals Apply molecular monitoring methods to conserved, threatened, and endangered species (i.e. difficult to study in the lab). Apply strategy to species / populations / communities that are most at risk to changing crop practices. Ensure the safety of biotech crops by monitoring potential environmental problems.
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Acknowledgements Ecological Exposure Research Division/ Molecular Ecology Research Branch Mark Bagley Jim Lazorchak Sobran Inc.
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