rhizobium gallicum rhizobium gallicum rhizobium gallicum is a gram-negative root-nodule bacterium. it forms nitrogen-fixing root nodules on legumes, being first isolated from those of phaseolus vulgaris. rhizobium gallicum scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: rhizobiaceae genus: rhizobium species: r. gallicum binomial name rhizobium gallicumamarger et al. 1997 biovars symbiovar gallicum symbiovar orientale symbiovar phaseoli synonyms rhizobium azibense mnasri et al. 2014