Cross-talk between the two-component regulatory systems NodVW and NwsAB ofBradyrhizobium japonicum

The protein products of the Bradyrhizobium japonicum gene pairs nodVW and nwsVW are members of the bacterial two-component regulatory systems. While NodW and NwsB exhibit all of the characteristics of the response-regulator class, NodV and NwsA contain the conserved domain of the sensor-kinase family. Overexpression of the nwsB gene results in complementation of the nodulation defect of a nodW mutant. We report here that the NwsB protein, unlike the overproduced NodW protein, requires NodV or NwsA for its function. This shows that cross-talk occurs between NwsAB and NodVW, in that NodV appears to activate NwsB.