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METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES
Citation:
WATRUD, L. S., J. R. REICHMAN, E. LEE, C. A. BURDICK, AND A. FAIRBROTHER. METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES. Presented at Board of Scientific Councilors Scientific Review, RTP, NC, February 01 - 03, 2007.
Description:
SCIENCE QUESTIONS:
-Does gene flow occur from genetically modified (GM) crop plants to compatible plants?
-How can it be measured?
-Are there ecological consequences of GM crop gene flow to plant communities?
RESEARCH:
The objectives of the Gene Flow Project are to develop protocols to measure gene flow from GM crops and to determine the potential ecological consequences of GM gene flow on plant communities. The protocols will help inform regulatory decisions by the Office of Pesticide Programs on the environmental safety of GM plants that express pesticidal plant incorporated protectants (PIPs). Two model crops are used in our methods development: creeping bentgrass (Agrostis stolonifera) which is a perennial, wind-pollinated moncot and canola (Brassica napus) which is a dicot annual that is predominantly insect-pollinated.
Initial efforts in the Gene Flow Project have focused on use of herbicide tolerant creeping bentgrass to develop and validate methods for measuring exposure to GM gene flow on a landscape level. Findings from the first 3 years of research have resulted in a change in the paradigm for how far viable pollen may move from GM crop source fields, from a scale of meters to kilometers. They also have resulted in documentation of the first establishment of GM crop/wild hybrids in non-agronomic environments in the U.S.
Our future research direction is focused on methods development to determine potential consequences of gene flow on the ecological fitness of recipients and also on the composition of plant communities which may contain GM crop/wild hybrids or feral GM seeds. To that end, we have designed unique greenhouse-sized outdoor mesocosms for confinement of GM pollen and seeds. Multi-year, multi-species plant community studies carried out in within the mesocosms will allow us to determine the potential ecological effects of gene flow from GM crops on plant community composition and biomass. Future effects studies will examine consequences of gene flow in the presence and absence of selective pressures for the GM traits of interest. We will focus on the use of GM plants that contain pesticidal traits for insect or disease resistance. Longer term, we plan to examine effects of gene flow +/- selective pressures and/or environmental stressors (e.g. drought or nutrients), in communities which contain plants with stacked (multiple) GM traits.
In conjunction with the above studies, molecular studies will be carried out track introgression into recipient wild populations, to develop population level markers, and to confirm the species identities of donors and recipients of GM genes.
IMPACTS AND OUTCOMES:
¿ In a period of only 3 years, the Gene Flow Project team has helped inform Agency and incidentally USDA regulatory decisions on the potential scale of exposure to GM genes on a landscape level. Regulators and seed producers may now need to consider longer isolation distances or buffer areas around experimental or production fields, particularly for wind-pollinated crops which may have sympatric, co-flowering relatives. They may also need to consider using smaller experimental field plots to limit the extent of gene flow. Surveys for compatible plants in the areas proposed for experimental or commercial production of GM plants may also be needed, depending on the particular crop.
¿ Outputs have included two peer-reviewed publications which appeared in major scientific journals. They describe methods to measure gene flow and how to survey for GM-gene containing plants that may have become established in non-agronomic environments. These two publications have received high-level Agency awards and recognition in the public media.