A revision of Rhizobium Frank 1889, with an emended description of the genus, and the inclusion of all species of Agrobacterium Conn 1942 and Allorhizobium undicola de Lajudie et al. 1998 as new combinations: Rhizobium radiobacter, R-rhizogenes, R-rubi, R-undicola and R-vitis

Rhizobium, Agrobacterium and Allorhizobium are genera within the bacterial family Rhizobiaceae, together with Sinorhizobium. The species of Agrobacter ium, Agrobacterium tumefaciens (syn, Agrobacterium radiobacter). Agrobacter ium rhizogenes, Agrobacterium rubi and Agrobacterium vitis, together with A llorhizobium undicola, form a monophyletic group with all Rhizobium species , based on comparative 16S rDNA analyses. Agrobacterium is an artificial ge nus comprising plant-pathogenic species. The monophyletic nature of Agrobac terium, Allorhizobium and Rhizobium and their common phenotypic generic cir cumscription support their amalgamation into a single genus, Rhizobium. Agr obacterium tumefaciens was conserved as the type species of Agrobacterium, but the epithet radiobacter would take precedence as Rhizobium radiobacter in the revised genus. The proposed new combinations are Rhizobium radiobact er, Rhizobium rhizogenes, Rhizobium rubi, Rhizobium undicola and Rhizobium vitis.