Gene flow from cultivated rice (Oryza sativa) to its weedy and wild relatives.
OBJECTIVE
Transgene escape through gene flow from genetically modified (GM) crops to their wild relative species may potentially cause environmental biosafety problems. The aim of this study was to assess the extent of gene flow between cultivated rice and two of its close relatives under field conditions.


METHODS
Experiments were conducted at two sites in Korea and China to determine gene flow from cultivated rice (Oryza sativa L.) to weedy rice (O. sativa f. spontanea) and common wild rice (O. rufipogon Griff.), respectively, under special field conditions mimicking the natural occurrence of the wild relatives in Asia. Herbicide resistance (bar) and SSR molecular finger printing were used as markers to accurately determine gene flow frequencies from cultivated rice varieties to their wild relatives.


RESULTS
Gene flow frequency from cultivated rice was detected as between approx. 0.011 and 0.046 % to weedy rice and between approx. 1.21 and 2.19 % to wild rice under the field conditions.


CONCLUSIONS
Gene flow occurs with a noticeable frequency from cultivated rice to its weedy and wild relatives, and this might cause potential ecological consequences. It is recommended that isolation zones should be established with sufficient distances between GM rice varieties and wild rice populations to avoid potential outcrosses. Also, GM rice should not be released when it has inserted genes that can significantly enhance the ecological fitness of weedy rice in regions where weedy rice is already abundant and causing great problems.
Chen
Li Juan
LJ
School of Biological Resources, College of Natural Resources, Yeungnam University, Kyongsan 712-749, South Korea.
Lee
Dong Sun
DS
Song
Zhi Ping
ZP
Suh
Hak Soo
HS
Lu
Bao-Rong
BR
D002681:China; D016172:DNA Fingerprinting / Q000379:methods; D004351:Drug Resistance / Q000235:genetics; D004463:Ecology; D006540:Herbicides / Q000378:metabolism / Q000494:pharmacology; D006824:Hybridization, Genetic / Q000235:genetics; D007723:Korea; D018598:Minisatellite Repeats / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics*; D019076:Transgenes / Q000235:genetics*
D006540:Herbicides