Rhizobium vignae sp. nov., a symbiotic bacterium isolated from multiple legume species

Abstract

A group of rhizobial strains isolated from nodules of multiple legume species grown in different geographical regions of China had identical 16S rRNA genes. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the novel strains formed a subclade in the genus Rhizobium together with Rhizobium galegae, Rhizobium huautlense and Rhizobium alkalisoli, with 99.8 % gene sequence similarity between the strains. The DNA–DNA relatedness values between the representative strain CCBAU 05176T and R. galegae ATCC 43677T, R. huautlense S02T and R. alkalisoli CCBAU 01393T were 22.6 %, 8.9 % and 15.9 %, respectively. The novel strains were distinguished from recognized species of the genus Rhizobium by using a polyphasic approach, including PCR-based restriction fragment length polymorphism analysis (RFLP) of the 16S–23S intergenic spacer (IGS), phenotypic and physiological tests, sequence comparisons of housekeeping genes and cellular fatty acid profiles. Therefore, it is suggested that this group of strains represents a novel species for which the name Rhizobium vignae sp. nov. is proposed. The type strain is CCBAU 05176T (=HAMBI 3039T=LMG 25447T).