Rhizobium binxianense sp. nov. and Rhizobium mulingense sp. nov., isolated from nodules of Phaseolus vulgaris in Heilongjiang Province of China.

Rhizobial isolates from Phaseolus vulgaris (common bean) grown in Heilongjiang Province were grouped into two clusters based upon the phylogenies of 16S rRNA and recA-atpD genes representing by BJ04, MJ22, MJ37, BC56, MC62 and MC63, MJ21, MJ31, respectively. The phylogenetic analysis of whole genomes further revealed that BJ04, MJ22, MJ37, BC56 and MC62 formed a cluster neighbored Rhizobium chutanense C5, while MC63, MJ21 and MJ31 formed a cluster most related with Rhizobium croatiense 13T. The whole genome average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the strains BJ04 and R. chutanense C5 and between MC63 and R. croatiense 13T were lower than the species thresholds 95 % and 70 %, respectively. While the G + C content of the whole genome of the novel strains were 61.16-61.56 %, within the allowable GC content range of the Rhizobium genus (57-66 %). These results, combined with chemical classification and phenotype analysis, supported that BJ04 and MC63 represented two novel species and the names Rhizobium binxianense sp. nov. and Rhizobium mulingense sp. nov. were described for them. BJ04 (=CCTCC AB 2022367, = JCM 35885) and MC63 (=CCTCC AB 2024025, = JCM 36652) were designed as the type strains, respectively for these two novel species.