Mesorhizobium albiziae sp. nov., a novel bacterium that nodulates Albizia kalkora in a subtropical region of China.

A novel Mesorhizobium group associated with Albizia kalkora [ Wang et al. (2006) , Syst Appl Microbiol 29, 502–517] was further characterized. The seven strains in this group showed similar protein patterns and were different from defined Mesorhizobium species in SDS-PAGE of whole-cell proteins. The representative strain CCBAU 61158T formed a novel Mesorhizobium lineage in phylogenetic analyses of 16S rRNA, atpD, glnII and nifH genes. However, its nodC gene sequence was more similar to that of Rhizobium gallicum R602spT than to those of Mesorhizobium species. DNA–DNA relatedness between CCBAU 61158T and reference strains of defined Mesorhizobium species was lower than 34.1 %. These results indicated that this Mesorhizobium group was a unique genomic species. The subtropical distribution, host origin, PCR-RFLP patterns of 16S rRNA genes, fatty acid profile and a series of phenotypic characteristics could be used as distinctive features of this group. This group is therefore proposed as a novel species, Mesorhizobium albiziae sp. nov., with CCBAU 61158T (=LMG 23507T=USDA 4964T) as the type strain. Strain CCBAU 61158T could form effective nodules on Albizia julibrissin, Glycine max, Leucaena leucocephala and Phaseolus vulgaris.