Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 7, 1996
Publication Date: N/A
Interpretive Summary: Rhizobia are important soil bacteria with application in Agricultural production. These bacteria establish symbioses with legumes, many of which are important crops. The symbiosis benefits the plant because the bacteria fix inert gaseous nitrogen into a form the plant uses for growth and production. Therefore, management of the symbiosis and rhizobia is part of efficient crop production in low input sustainable agriculture. A problem in the management of rhizobia is that there is considerable genetic variation in the capacity for nitrogen fixation. Therefore, genetic characterization of rhizobia and the development of methods for their positive identification both in nature and in the laboratory are of paramount importance. These studies document phylogenetic relationships among several bacterial legume symbionts. Recently, the advancements in taxonomy of legume symbionts has been so dramatic that current classification schemes were no longer relevant. Therefore we have assembled the evidence for the description of a new genus and amended the descriptions of the species within this new genus. This information will become part of the classification schemes of the legume symbionts to be used by scientists, the media, and in industry when there is a need to identify or discuss these bacteria.
Reasons are advanced for the removal of Rhizobium ciceri, Rhizobium huakuii, Rhizobium loti, Rhizobium mediterraneum, and Rhizobium tianshanenese from the genus Rhizobium and establishment of Mesorhizobium gen. nov., for these species. Descriptions are provided for Mesorhizobium and amended descriptions for Mesorhizobium ciceri, Mesorhizobium huakuii, Mesorhizobium loti, and Mesorhizobium tianshanenese.