PHYLOGENETIC AND GENETIC-RELATIONSHIPS OF MESORHIZOBIUM TIANSHANENSE AND RELATED RHIZOBIA

The genetic and phylogenetic relationships for strains of Mesorhizobiu m tianshanense and its relatives were compared by an analysis of the r esults of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (S DS-PAGE) of whole-cell proteins, DNA-DNA hybridization, and full 16S r RNA gene sequencing. The strains of ill tianshanense formed a cluster Which Was distinct from those of other rhizobium species in the cluste ring analysis of SDS-PAGE. DNA-DNA relatedness between A-1BS (type str ain of M. tianshanense) and the type or reference strains for Mesorhiz obium loti, M. huakuii, M. ciceri, M. mediterraneum, and cluster U, an unnamed rhizobial group, ranged from 4.4 to 43.8%. The phylogenetic a nalysis based on the 16S rRNA gene sequences showed that M. tianshanen se was closely related to the Mesorhizobium phylogenetic branch and co uld be distinguished from the other four species in this branch. These results further confirmed that these bacteria constitute a distinct r hizobial species.