Genetic diversity and phylogeny of soybean rhizobia isolated from the Hilly Area of Central Sichuan in China

Abstract:

Abstract:［Objective］We investigated the genetic diversity and phylogeny of 28 rhizobial isolates from root nodules of soybean growing in the Hilly Area of Central Sichuan in China.［Methods］We used 16S rDNA PCR-RFLP and phylogenetic analyses of the 16S rDNA，glnII and symbiotic genes (nodC).［Results］Five 16S rDNA genotypes among the isolates were distinguished with restriction endonucleases HaeⅢ，HinfⅠ，MspⅠand TaqⅠ．In the 16S rDNA PCRRFLP analysis，all the isolates are divided into Bradyrhizobium group and Sinonrhizobium group at the 83% level，and Sinonrhizobium strains accounted for 75% of the isolates．The phylogenetic analyses of 16S rDNA，glnII and nodC show that 4 representative strains SCAUs1，SCAUs2，SCAUs7 and SCAUs4 were closely related to S．fredii USDA205Twhile the other 2 representative strains SCAUs3 and SCAUs5 were closely related to B. yuanmingense CCBAU10071T and B． diazoefficiens USDA110T．The 16S rDNA，glnII and nodC sequence similarity of 4 Sinonrhizobium representative strains were 98.3%－99.9%，98.2%－100% and 100%，respectively.［Conclusion］Soybean rhizobia isolated from the Hilly Area of Central Sichuan in China has rich genetic diversity，S．fredii was the predominant genus.