title: Glyphosate-drift but not herbivory alters the rate of transgene flow from single and stacked trait transgenic canola (Brassica napus) to nontransgenic B. napus and B. rapa.
abstract: • Transgenic plants can offer agricultural benefits, but the escape of transgenes is an environmental concern. In this study we tested the hypothesis that glyphosate drift and herbivory selective pressures can change the rate of transgene flow between the crop Brassica napus (canola), and weedy species and contribute to the potential for increased transgene escape risk and persistence outside of cultivation. • We constructed plant communities containing single transgenic B. napus genotypes expressing glyphosate herbicide resistance (CP4 EPSPS), lepidopteran insect resistance (Cry1Ac), or both traits ('stacked'), plus nontransgenic B. napus, Brassica rapa and Brassica nigra. Two different selective pressures, a sublethal glyphosate dose and lepidopteran herbivores (Plutella xylostella), were applied and rates of transgene flow and transgenic seed production were measured. • Selective treatments differed in the degree in which they affected gene flow and production of transgenic hybrid seed. Most notably, glyphosate-drift increased the incidence of transgenic seeds on nontransgenic B. napus by altering flowering phenology and reproductive function. • The findings of this study indicate that transgenic traits may be transmitted to wild populations and may increase in frequency in weedy populations through the direct and indirect effects of selection pressures on gene flow.
authors: National Research Council, 200 SW 35th Street Corvallis, OR 97333, USA.|Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Jason P
authors: JP
authors: Londo
authors: US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, 200 SW 35th Street Corvallis, OR 97333, USA.
authors: Michael A
authors: MA
authors: Bollman
authors: Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA.
authors: Cynthia L
authors: CL
authors: Sagers
authors: US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, 200 SW 35th Street Corvallis, OR 97333, USA.
authors: E Henry
authors: EH
authors: Lee
authors: US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Western Ecology Division, 200 SW 35th Street Corvallis, OR 97333, USA.
authors: Lidia S
authors: LS
authors: Watrud
mesh_terms: D000818:Animals; D044822:Biodiversity; D001937:Brassica / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology; D029688:Brassica napus / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D029741:Brassica rapa / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D051456:Gene Flow / Q000235:genetics*; D005838:Genotype; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D053209:Herbicide Resistance / Q000235:genetics; D007915:Lepidoptera / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D012098:Reproduction / Q000502:physiology; D012639:Seeds / Q000235:genetics / Q000254:growth & development; D012641:Selection, Genetic; D019076:Transgenes / Q000235:genetics; D000097797:Glyphosate
chemical_list: D005998:Glycine; D000097797:Glyphosate