rhizobium lusitanum rhizobium lusitanum rhizobium lusitanum is a gram negative root nodule bacteria, specifically nodulating phaseolus vulgaris. its type strain is p1-7t (=lmg 22705t =cect 7016t). rhizobium lusitanum scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: rhizobiaceae genus: rhizobium species: r. lusitanum binomial name rhizobium lusitanumvalverde et al. 2006