Lu, Baorong .
Transgene introgression into crop wild relative species: Its genetic impacts on biodiversity conservation.
Crop wild relative (CWR) species play an essential role in the global food production, offering elite genetic resources for the improvement of cultigens. Safeguarding and conservation of biodiversity in the CWR gene pool is the continued endeavor of plant breeders and geneticists. Effective conservation ensures the long-term availability and utilization of the valuable genetic resources in CWR gene pool. However, with the continued increase in human population, urbanization, and the rapid growth of economy and industry in developing countries, CWR species are under severe threat. For example, in 1970s the Chinese Academy of Agricultural Sciences (CAAS) organized extensive field expeditions in southern China to conserve wild rice (Oryza rufipogon Griff.) that is the direct ancestor of Asian cultivated rice (O. sativa L.) and valuable genetic resources for rice breeding. Unfortunately, at the end of 1990s when CAAS revisited the sites where wild rice populations were sampled in the previous expeditions, only <20% sides were found and many of the survived wild rice had a much reduced population size. This illustrates the endangered status of CWR species in China, possibly in many other countries too. It is a consensus that the following reasons are responsible for the extinction of wild rice populations: (1) habitat deterioration owning to the improper land-uses; (2) expansion or change of agricultural fields; (3) disturbances by human activities; and (4) heavy animal grazing. Importantly, a factor that can significantly influence the biodiversity and genetic integrity of CWR species has not been well recognized. That is the introgression of crop alleles into CWR populations through recurrent pollen-mediated gene flow, which has great impacts on the genetic diversity, structure, and integrity of the CWR populations by such effects as demographic swamping, genetic assimilation, and selective sweep. The rapid increase in global cultivation areas of genetically modified (GM) crops has aroused worldwide concerns over the environmental biosafety issues. Impacts of transgene introgression from GM crops into CWR populations that are targeted for biodiversity conservation either by ex situ or in situ means become an increasingly debated issue. However, our understanding of genetic and ecological mechanisms of crop-wild transgene introgression on biodiversity conservation is very limited. This presentation will provide theoretical reasoning and empirical evidence to address the issues of transgene introgression into CWR populations and its potential impacts on the long-term conservation of CWRs.
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1 - Department of Ecology and Evolutionary Biology, School of Life Sciences, Fudan University, Handan Rd. #220, Shanghai, 200433, China
Presentation Type: Oral Paper:Papers for Topics
Location: Union C/Hyatt
Date: Tuesday, July 10th, 2012
Time: 10:30 AM