Agrobacterium tumefaciens has homologues of chemotaxis genes of the alpha-subgroup of proteobacteria, which include orf1, orf2, cheY1, cheA, cheR, cheB, cheY2, orf9, and orf10 and organized in one operon [Wright et al. A chemotaxis cluster from Agrobacterium tumefaciens. Gene 1998;220:83-9]. Two mutants of A. tumefaciens were created by in-frame deletions of cheB and cheR using suicide vector, pK18mobsacB. The chemosensory behaviour of mutants studied on swarm plates and in blind-well chemotaxis assay toward acetosyringone. Under the conditions tested, both CheR and CheB were essential for normal chemotaxis.
