azorhizobium caulinodans azorhizobium caulinodans azorhizobium caulinodans is a species of bacteria that forms a nitrogen-fixing symbiosis with plants of the genus sesbania. the symbiotic relationship between sesbania rostrata and a. caulinodans lead to nitrogen fixing nodules in s. rostrata. bacterial chemotaxis plays an important role in establishing this symbiotic relationship. azorhizobium caulinodans scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: xanthobacteraceae genus: azorhizobium species: a. caulinodans binomial name azorhizobium caulinodansdreyfus et al. 1988 azorhizobium caulinodans is a genome and it contains chemotaxis gene clusters that are unique. it has five chemotaxis genes which are: chew(1), chew, chea, cher, and cheb. azorhizobium caulinodans controls the movements of flagella, and the chemotaxis signaling path in azorhizobium caulinodans helps with regulating biofilm formation.