Genetic diversity and phylogeny of bradyrhizobia associated with Desmodium spp．

Abstract:

Abstract:［Objective］Genetic diversity and phylogeny of bradyrhizobial strains associated with Desmodium spp． in subtropic and temperate regions of China were analyzed．［Methods］ We studied 29 desmodia isolates from different regions with BOX-PCR fingerprinting and multilocus sequence analysis ( nifH，nodC and recA gene) to describe the genotypic characteristics and phylogenetic relationships．［Results］ We achieved 25 genotypes with BOX-PCR genomic fingerprinting analysis，indicating that the tested strains had a great diversity at genomic level． The representative bradyrhizobial strains were located in three phylogenic branches with multilocus sequence analysis (nifH，nodC and recA gene)，that was closely related to Bradyrhizobium elkanii，Bradyrhizobium japonicum and Bradyrhizobium yuanmingense，respectively．［Conclusion］The desmodia bradyrhizobia had abundantly diversity． Diverse symbiotic genes including nifH and nodC genes were also found in these strains that indicated that the symbiotic genes were mainly maintained by vertical transfer in these bradyrhizobial populations and coevolved with housekeeping genes．

Key words:Keywords: desmodia bradyrhizobia，BOX-PCR，multilocus sequence analysis，genetic diversity，phylogeny