Enhancement of nitrogen fixation with Bradyrhizobium japonicum mutants

摘要

A prototrophic revertant of a Bradyrhizobium japonicum tryptophan auxotroph was isolated and found to fix more nitrogen symbiotically than wild-type bacteria. The increase in nitrogen fixation is due to an increase in nodule mass because of an increase in nodule number. The physiological basis for this improved symbiosis appears to be an alteration of the tryptophan biosynthetic pathway.