Nitrogen-fixing bacterium. Sinorhizobium meliloti 1021

Sinorhizobium meliloti strain 1021. Streptomycin resistant derivative of strain 2011. This strain carries 2 megaplasmids, pSymA and pSymB. Nitrogen fixation functions and nodulation genes are found on pSymA. The second plasmid encodes a number of transport systems, including many ABC-type transporters. This organism does not have a type III secretion system like the other Rhizobia but does have a type IV secretion system.