Diversity And Phylogeny Analysis Of Vicia Sepium Rhizobia Isolated From The Northwest Of China

49 root-nodulating bacteria isolated from vicia, which grew in the regions of Xinjiang, Gansu, Shaanxi and Ningxia, were studied by performing the method of polyphasic taxonomy including genetic and phenotypic analysis such as 16S rDNA PCR-RFLP, IGS PCR-RFLP and phylogenic study of 16S rDNA gene, nodA gene and nifH gene, and numerical taxonomy of 105 physiological and chemical characteristics.12 different genotypes were obtained by the analysis of 16S rDNA PCR-RFLP. The phylogenetic positions of representative strains were revealed by 16S rDNA gene sequences. The similarities of R. leguminosarum(USDA2370)to CCNWSX0050, CCNWGS0055 and CCNWGS0059 were 99.6%, 99.5% and 99.4% respectively, which demonstrated that the tested strains with genotype 2, genotype 4 and genotype 6 belonged to R. leguminosarum.And the DNA homology of CCNWGS0061 and CCNWGS0062 to reference strains showed that they belonged to species of S. fredii and S. xingjiangense respectively. In addition, CCNWGS0062 was located in the same branch to S. meliloti, S. medicae and S. arboris on the similarities of 100%, 99.7% and 98.1% respectively. On the other hand, the result of IGS PCR-RFLP showed that the tested strains had 21 different genotypes, highlighted the diversity of vicia rhizobia in northwest of China。The result of nodA PCR-RFLP showed that there were five kinds of genotypes, and the result of phylogenetic analysis was surpported by the 16S rDNA sequences analysis. The majority of the tested strains were certained in the branch of Sinorhizobium and Rhizobium.The physiological and chemical characteristics of the tested and reference strains were studied. The result indicated all the tested strains were divided into 4 groups on the 89% similarity. Group I included 23 strains on the 89% similarity level. Group II included 5 tested strains on the 81% similarity with the reference strain M. septentrionale. GroupⅢincluded 10 strains on the 87% similarity level with the reference strain S. fredii. GroupⅣincluded 3 strains on the similarity of 81%.The nodulation test indicated that the inporation of the nodulated to plants of the tested strains was corrospondingly high, and the promoting effect was obvious showing by the dry weight of the plants.