This phylogenetic tree shows relatedness to the rest of the Rhizobiaceae family based on 16s rRNA gene sequences.

It performs atmospheric nitrogen fixation for the plants and in exchange it receives organic carbon through the process of rhizodeposition.

[3] The extent of the mutualism may be dependent upon soil pH, as it was thought that acidity can constrain Sinorhizobium medicae.

Current thinking is that acid resistance, particularly in strain WSM419, can be transferred on plasmids.

The SRDI554 strain is highly halotolerant, making it an ideal inoculum for the salt-tolerant pasture legume Melilotus siculus (messina).