rhizobium mongolense rhizobium mongolense rhizobium mongolense is a gram negative root nodule bacteria, which nodulates and forms nitrogen-fixing symbioses with medicago ruthenica. its type strain is usda 1844. rhizobium mongolense scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: rhizobiaceae genus: rhizobium species: r. mongolense binomial name rhizobium mongolensevan berkum et al. 1998 synonyms rhizobium loessense wei et al. 2003