Diversity And Phylogeny Of Rhizobia Isolated From Oxytropis In Pamirs Of China

The rhizobial taxonomy and methods used for polyphasic taxonomy were reviewed. Twenty six isolates from nodules of Oxytropis in Pamirs of China, which are important plants used as herbal medicine,as a windbreak or cover plant to protect the soil from erosion, were analyzed by phenotypic and genetic analysis such as numerical taxonomy,16S rDNA PCR-RFLP, BOX-PCR, IGS PCR-RFLP and phylogenic study based on 16S rDNA sequences.The physiological and chemical characteristics of all isolates were tested and the results indicated all strains could grow in high salinity level and in low temperature circumstance.All strains have the excellent anti character to antibiotics and dye.The result of numerical taxonomy showed that all the test strains were divided into 2 Groups on the 80% similarity.The frist Group includes 16 strains on the 80% similarity level and the main strain is CCNWXJHQ041-1,the second Group includes 9 strains on the 81% similarity level and the main strain is CCNWXJHQ048-1.Based on the numerical taxonomy, the fingerprint of 5 gene fragments were studied by using PCR-RFLP. The PCR-RFLP result of 16S rDNA showed that all the test strains were divided into 3 Groups on the 80.0% similarity. And the first group was divided into two subgroups on the 92.0 % similarity level. In the first subgroup, there are nine test strains and in the second subgroup also.The second Group includes 2 strains on the 80% similarity level. The third Group includes 4 strains on the 80% similarity level.The PCR-RFLP result of 23S rDNA showed that all the test strains were divided into 3 Groups on the 77.0% similarity.In the first group, there are 18 test strains on the 95% similarity level.The second Group includes 5 strains on the 77% similarity level.The third Group includes 3 strains on the 86% similarity level.The PCR-RFLP result of 16-23S IGS rDNA showed that all the test strains were divided into 5 Groups on the 82.0% similarity.In the first group, there are 9 test strains on the 84% similarity level.The second Group includes 4 strains on the 82% similarity level.The third Group includes 7 strains on the 100% similarity level. The fourth Group includes 3strains on the 87% similarity level.The fifth Group includes 3strains on the 82% similarity level .BOX-RFLP fingerprint analyse is also an important measure to research the diversity of rhizobia.The BOX-RFLP result showed that all the test strains were divided into 3 Groups on the 79.0% similarity.In the first group, there are 6 test strains on the 82% similarity level.The second Group includes 3 strains on the 79% similarity level.The third Group includes 7 strains on the 89% similarity level.The result of PCR-RFLP showed that the Rhizobia isolated from Oxytropis in Pamirs have rich phenotypic and genetic diversity.Through the 16S rRNA gene sequences analysis,6 represented strains belong to Sinorhizobium, Agrobacterium and Rhizobium.