Rhizobium herbae sp nov and Rhizobium giardinii-related bacteria, minor microsymbionts of various wild legumes in China

Seven Rhizobium strains associated with various legume species grown in different geographical regions of China were defined into four genomic groups related to Rhizobium giardinii, based upon ribosomal intergenic spacer RFLP, phylogenies of 16S rRNA and housekeeping (atpD, recA and glnII) genes, and DNA relatedness. Three strains in group I were classified as R. giardinii, as they showed high gene sequence similarities (> 97%) and DNA relatedness (64.3-67.5 %) to R. giardinii H152(T). Groups II, III and IV differed from all defined Rhizobium species based upon the consensus of all analyses. As group II contained two strains that originated from two distinct populations, we propose this group as a novel species, Rhizobium herbae sp. nov., with strain CCBAU 83011(T) (=LMG 25718(T)=HAMBI 3117(T)) as the type strain.