[Genetic diversity and phylogeny of soybean rhizobia isolated from the regions of Loess Plateau in China].

ABSTRACT

OBJECTIVE: We investigated the genetic diversity and phylogeny of soybean rhizobia isolated from the regions of Loess Plateau in China. METHODS: We analyzed 130 soybean rhizobia isolated from 15 regions in 4 provinces of Loess Plateau through BOX-PCR, 16S rDNA PCR- RFLP, 16S-23S IGS PCR-RFLP and 16S rRNA gene sequencing. RESULTS: BOX-PCR, 16S rDNA PCR- RFLP and 16S-23S IGS PCR-RFLP were in good agreement with the results which showed that all strains tested ascribed to two groups the genus of Sinorhizobium and Bradyrhizobium phylogenetically. The analysis of 16S rRNA gene of 5 representative strains indicated that they were related to type strains S. fredii, B. japonicum and B. liaoningense, homology coefficient with type strains was 100% respectively. CONCLUSION: Soybean rhizobia isolated from the regions of Loess Plateau in China showed rich genetic diversity. S. fredii was the dominant species. Bradyrhizobium accounted for 10% of the strains tested only, of which, two strains were B. liaoningense.