Characterization of Bradyrhizobium species isolated from root nodules of Cytisus villosus grown in Morocco

From a total of 73 bacterial strains isolated from root nodules of Cytisus villosus grown in soils of the central-western region of the Moroccan Rif, 68 strains clustered into 19 repetitive extragenic palindromic (REP)-polymerase chain reaction (PCR) groups. The nearly complete 16S rRNA gene sequence from each strain showed they were closely related to members of the genus Bradyrhizobium of the Alphaproteobacteria, but affiliation at the species level was not clear. Sequencing of the housekeeping genes glnII and recA, and their concatenated phylogenetic analysis showed that 11 out of the 19 strains belong to Bradyrhizobium canariense and that another three strains were Bradyrhizobium japonicum. The remaining five strains represented new lineages within the genus Bradyrhizobium since they were not identified with any previously described species. Sequencing of the symbiotic nodC and nifH genes from each bradyrhizobial strain revealed they were all similar to those of the strains included in biovar genistearum.