MODERN CONCEPTS OF THE PHYLOGENY AND TAXONOMY OF NODULE BACTERIA

Data on the diversity of legume microsymbionts are considered. Accordi ng to the modern taxonomic system, nodule bacteria are grouped into fo ur genera: Rhizobium, Bradyrhizobium, Sinorhizobium, and Azorhizobium. The idea of a fifth genus, ''Mesorhizobium,'' is discussed. Phylogene tically, strains of different rhizobial genera are only distant relati ves. The possibility of smoothing over the contradictions between the formal classification of nodule bacteria and data on their phylogeny i s discussed.