Références sur les Plantes

URL: http://www.sciencedirect.com/science/article/B6WPC-509W75K1/2/359d34b6366d0c760d4cef823149ad5f Author Address: a Institute for Plant Genomics and Biotechnology, Texas A&M University, USA b Department of Plant Pathology and Microbiology, College Station, TX 77843, USA c Department of Plant Pathology, University of California, Davis, CA 95616, USA XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Author: Kaga A, Kuroda Y, Kitamoto N, Tomooka N, Ohsawa R, Vaughan D, Year: 2008 Title: 造 Studies on gene dispersal from soybean to wild soybean growing in their natural habitat in Japan.

Journal: 10th ISBGMO - 10th International Symposium on the Biosafety of Genetically Modified Organisms Biosafety research : Past Achievements and Future Challenge - Museum of New Zealand Te Papa Tongarewa Cable St., Wellington, New Zealand, Sunday 16 November - Friday 21 November 2008 http://www.isbr.info/sites/default/files/symposia/10th_symposium-2008.pdf Label: Dispersion Abstract: Soybeans [Glycine max (L.) Merrill] and wild soybeans (Glycine soja Sieb. & Zucc.) are sympatric across much of Japan. The objectives of our studies are to assess cross-pollination between soybean and wild soybean in their natural habitat and whether escaped genes from soybean become established in wild populations.

Genetic structure of wild and cultivated soybean The genetic structure of Japanese wild soybean populations and modern cultivated soybean varieties was characterized using 20 microsatellite markers, one for each linkage group. 616 fi eld collected individuals from 77 wild soybean populations from across Japan were compared with 53 varieties of cultivated soybean that covered more than 95% of recent soybean planting area in Japan.

Average out-crossing rate in Japanese wild soybean populations was 3.4% but for several populations it exceeded 10%. High outcrossing rate and seed migration between populations were considered important factors for secondary gene spread. Among 20 SSR markers, 7 showed clear allelic differentiation between cultivated and wild soybean and are useful for marker-based evaluation of gene introgression.

Intermediates between wild soybean and soybean To clarify fi eld gene introgression from cultivated soybean into wild soybean populations, fi eld surveys were conducted throughout Japan over fi ve years. Individual wild soybean plants in populations around or near soybean fi elds were carefully checked. Obvious natural hybrid derivatives between wild and cultivated soybean were found in northern and southern Japan. A morphologically intermediate individual was found about 15m from soybean fi elds in Akita, northern Japan in 2003. In Saga, southern Japan, in 2004 10 intermediate individuals from 3 sites were found in wild populations. Among these three sites, we found two kinds of intermediate, one individual with dull green seed and seven individuals with black seed at Saga site 1.

During a survey conducted in Hyogo, Akita and Saga prefectures in 2006 at the similar scale as 2004, three intermediate plants were found at new two sites in Saga. In 2007, one intermediate was identifi ed from Yamagata, northern Japan.

Natural hybrids between wild soybean and soybean Using the 20 microsatellite markers and chloroplast CAPS markers, gene dispersal from cultivated soybean in wild soybean populations was evaluated. Genotypes of intermediate individuals and 20-55 individuals from wild soybean populations where these intermediates were found were compared with samples from adjacent soybean fi elds. The intermediate from Akita in 2003, three intermediates from Saga in 2004, three intermediates from Saga in 2006, one from Yamagata in 2007 had the same chloroplast type as wild soybean, revealed heterozygosity at all microsatellite loci that distinguish wild and cultivated soybean and had one allele each from wild soybean and cultivated soybean. Thus these intermediates are natural F1 hybrids of wild soybean to which soybean out-crossed. Compared with these intermediates with dull yellow seed coat, the other seven individuals with black seed at Sags site 1 in 2004, had a lower heterozygosity and homozygous cultivated soybean alleles at several loci. The number of homozygous loci was different in individuals, suggesting that these are natural hybrid derivatives. Interestingly, these hybrid derivatives result from a cross between wild soybean and black seeded cultivar that is different from yellow or green seeded cultivars involved in the natural F1 hybrids with dull yellow seed coat.

Monitoring hybrid derivatives