Bradyrhizobium rifense sp. nov. isolated from effective nodules of Cytisus villosus grown in the Moroccan Rif

Two bradyrhizobial strains, CTAW71T and CTAW69, previously isolated from root nodules of Cytisus villosus, have been analysed using a polyphasic approach. These strains have identical 16S rRNA genes and their closest relative species is Bradyrhizobium cytisi, whose type strain CTAW11T presented 99.8% identity with respect to strain CTAW71T. Despite the closeness of the 16S rRNA genes, the housekeeping genes recA, atpD and glnII harboured by strain CTAW71T were divergent to those from B. cytisi CTAW11T, with identity values of 93%, 95% and 97%, respectively. These differences were congruent with DNA–DNA hybridization analysis that revealed an average of 37% relatedness between strain CTAW71T and B. cytisi CTAW11T. Phenotypic characteristics were identical for strains CTAW71T and CTAW69, but differed from those of the described species from genus Bradyrhizobium. Based on the genotypic and phenotypic data obtained in this study, we propose that strains CTAW71T and CTAW69 should be classified into a new species for which the name Bradyrhizobium rifense sp. nov. is proposed (type strain CTAW71T = LMG 26781T = CECT 8066T).