Polyphasic Taxonomy Of Rhizobia And Endophytes Isolated From Pongamia Pinnata

The genetic diversity and phylogeny of 18 rhizobium strains and 9 endophytes isolated from Pongamia pinnata in Guanzhou and Zhuhai, together with 7 reference strains, was analyzed by numerical taxonomy, BOXAIR-PCR,16S rDNA PCR-RFLP, sequences analysis of 16S rDNA.The result of numerical taxonomy showed that 18 rhizobial strains strains were divided into 4 phenotypic groups at the level of 91.5% similarity; and nine endophytic strains were divided into 3 phenotypic groups at the level of 80% similarity. Results of physiologic and biochemistry analysis showed that there were great diverse among these strains,88.9% of strains could grow at the origional pH5.0,58.9% of strains could resist 4% NaCl.The genetic diversity was analyzed by BOXAIR-PCR and 16S rDNAPCR-RFLP. BOXAIR-PCR analysis divided 18 rhizobial strains into 8 groups at 86% level of similarity; and 9 endophytic strains were divided into 4 groups at 71% level of similarity; 16S rDNA PCR-RFLP with four kinds of restriction endonucleases including Taqâ… ,Mspâ… ,Hinfâ… and Haeâ…¢.18 rhizobial strains have 7 genotypes, and 9 endophytes have 8 genotypes.The phylogenic tree of representative strains was constructed base on the 16S rDNA sequences. The results suggested that, the rhizobial strains were classified into genus Sinorhizobium, Ochrobactrum, Rhizobium and Agrobacterium. The sequence homology was 99.3% between PIN5 and type strain S. morelense Lc04T; and 99.9% between PIN4 and R. multihospitium CCBAU83401T; and 99.9% between strain PIN14 and R. alamii GBV016T. Interestingly, strains PIN8 and PIN26 had 100.0% and 99.6% homology of 16S rDNA sequence with Ochrobactrum lupini LUP21T. The 16S rDNA sequencing analysis divided 2 representative strains of endophytes into genus Kaistia and Burkholderia.