General Information: Streptomycin resistant derivative of strain 2011. Plant symbiotic bacterium. This organism, much like other Rhizobia, forms a symbiotic relationship with a leguminous plant, in this case the alfalfa plant (Medicago sativa). Expression of nodulation genes results in production of a nodulation signal which the plant cell recognizes inducing root nodule formation. The plant cell provides carbon compounds for the bacterium to grow on.