Bradyrhizobium monzae sp. nov. isolated from a root nodule of the introduced legume Crotalaria ochroleuca in Uruguay

A strain, namely Oc8 T , was isolated from a root nodule of Crotalaria ochroleuca in Uruguay. This strain induced effective nodules in roots of Crotalaria ochroleuca , Crotalaria juncea , Crotalaria spectabilis and Cajanus cajan . Oc8 T belongs to the genus Bradyrhizobium according to the results of the 16S rRNA gene sequence analysis, and it forms an independent lineage within a cluster encompassing 13 described species of this genus. From them, the type strains closest related to the strain Oc8 T with more than 99.5% similarity in 16S rRNA gene sequence were those of Bradyrhizobium ganzhouense , Bradyrhizobium cytisi , Bradyrhizobium guangdongense and Bradyrhizobium rifense (99.71%, 99.65%, 99.60% and 99.57%, respectively). A genome-based phylogeny showed that B. ganzhouense JCM 19881 T , B. cytisi CTAW11 T and B. rifense CTAW71 T were the closest type strains to the strain Oc8 T . Values lower than the species cutoff of 95% and 70% were found after average nucleotide identity and digital DNA–DNA hybridization calculation between the genome of the strain Oc8 T and those available genomes of the closest related Bradyrhizobium species. These results, together with those of the symbiotic nodC gene analysis, support the affiliation of this strain to the symbiovar cyanophyllae of a new species of Bradyrhizobium for which the name Bradyrhizobium monzae sp. nov. is proposed. The type strain is Oc8 T (=LMG 33261 T =CECT 30885 T ).