Pollen-mediated gene flow from transgenic to non-transgenic switchgrass (Panicum virgatum L.) in the field

BMC Biotechnology

Research Article

Charles Kwit¹  Rongjian Ye²  Chelsea R. Johnson²  Jason N. Burris²  C. Neal Stewart²  Reginald Millwood²  Micaha Hanson²  Ellie Terry-Emert²  Madhugiri Nageswara-Rao³ 

[1] Department of Forestry, Wildlife and Fisheries, University of Tennessee, 274 Ellington Plant Sciences, 2431 Joe Johnson Dr., 37996, Knoxville, TN, USA;Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., 37996, Knoxville, TN, USA;Department of Plant Sciences, University of Tennessee, 252 Ellington Plant Sciences, 2431 Joe Johnson Dr., 37996, Knoxville, TN, USA;Department of Biology, New Mexico State University, PO Box 30001, MSC 3AF, Las Cruces, NM, USA;

关键词: Switchgrass;    Bioenergy;    Hybridization;    Gene flow;    Pollen dispersal;    Transgenic;    Orange-fluorescent protein;    Biosafety;   

DOI  :  10.1186/s12896-017-0363-4

 received in 2017-01-10, accepted in 2017-04-25,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundSwitchgrass is C4 perennial grass species that is being developed as a cellulosic bioenergy feedstock. It is wind-pollinated and considered to be an obligate outcrosser. Genetic engineering has been used to alter cell walls for more facile bioprocessing and biofuel yield. Gene flow from transgenic cultivars would likely be of regulatory concern. In this study we investigated pollen-mediated gene flow from transgenic to nontransgenic switchgrass in a 3-year field experiment performed in Oliver Springs, Tennessee, U.S.A. using a modified Nelder wheel design. The planted area (0.6 ha) contained sexually compatible pollen source and pollen receptor switchgrass plants. One hundred clonal switchgrass ‘Alamo’ plants transgenic for an orange-fluorescent protein (OFP) and hygromycin resistance were used as the pollen source; whole plants, including pollen, were orange-fluorescent. To assess pollen movement, pollen traps were placed at 10 m intervals from the pollen-source plot in the four cardinal directions extending to 20 m, 30 m, 30 m, and 100 m to the north, south, west, and east, respectively. To assess pollination rates, nontransgenic ‘Alamo 2’ switchgrass clones were planted in pairs adjacent to pollen traps.ResultsIn the eastward direction there was a 98% decrease in OFP pollen grains from 10 to 100 m from the pollen-source plot (Poisson regression, F1,8 = 288.38, P < 0.0001). At the end of the second and third year, 1,820 F1 seeds were collected from pollen recipient-plots of which 962 (52.9%) germinated and analyzed for their transgenic status. Transgenic progeny production detected in each pollen-recipient plot decreased with increased distance from the edge of the transgenic plot (Poisson regression, F1,15 = 12.98, P < 0.003). The frequency of transgenic progeny detected in the eastward plots (the direction of the prevailing wind) ranged from 79.2% at 10 m to 9.3% at 100 m.ConclusionsIn these experiments we found transgenic pollen movement and hybridization rates to be inversely associated with distance. However, these data suggest pollen-mediated gene flow is likely to occur up to, at least, 100 m. This study gives baseline data useful to determine isolation distances and other management practices should transgenic switchgrass be grown commercially in relevant environments.

【 授权许可】

CC BY   
© The Author(s). 2017