Dual Oxygen-Responsive Control by RegSR of Nitric Oxide Reduction in the Soybean Endosymbiont .

To investigate the role of the RegSR-NifA regulatory cascade in the oxygen control of nitric oxide (NO) reduction in the soybean endosymbiont . We have performed an integrated study of expression and NO reductase activity in , , , , and mutants in response to microoxia (2% O) or anoxia. An activating role of RegR and NifA was observed under anoxia.