Physical and biochemical characterization of a competition and nodulation defective mutant of Azorhizobium caulinodans ORS571

The competitive ability of Azorhizobium caulinodans strain ORS571 was assessed using induced mutagenesis, which resulted in isolation of two mutants that were either defective in symbiotic properties or in competition for nodulation of Sesbania rostrata. One of the mutants was non-nodulating whereas the other one exhibited reduced competitiveness when inoculated along with the parent strain. Further characterization revealed that the non-nodulating mutant exhibited altered protein and lipopolysaccharide (LPS) profiles and the absence of flagella