title: A major chemotaxis gene cluster in Azospirillum brasilense and relationships between chemotaxis operons in alpha-proteobacteria.
abstract: Azospirillum brasilense shows chemotaxis to a variety of nutrients and oxygen. Genes encoding the central signal transduction pathway in chemotaxis were identified by phenotypic complementation of generally non-chemotactic mutants. Sequencing of a DNA fragment, which complemented two different mutants, revealed a region of five open reading frames translated in one direction and encoding homologs of known genes comprising excitation and adaptation pathways for chemotaxis in other bacterial species. The major chemotaxis gene cluster appears to be essential for all known behavioral responses that direct swimming motility in A. brasilense. Phylogenetic and genomic analysis revealed three groups of chemotaxis operons in alpha-proteobacterial species and assigned the A. brasilense operon to one of them. Interestingly, operons that are shown to be major regulators of behavior in several alpha-proteobacterial species are not orthologous.
authors.affiliation: Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, B-3001, Heverlee, Belgium.
authors.forename: Dieter
authors.initials: D
authors.lastname: Hauwaerts
authors.forename: Gladys
authors.initials: G
authors.lastname: Alexandre
authors.forename: Subrata K
authors.initials: SK
authors.lastname: Das
authors.forename: Jos
authors.initials: J
authors.lastname: Vanderleyden
authors.forename: Igor B
authors.initials: IB
authors.lastname: Zhulin
mesh_terms: D020561:Alphaproteobacteria / Q000235:genetics* / Q000502:physiology; D015806:Azospirillum brasilense / Q000235:genetics* / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002633:Chemotaxis / Q000235:genetics* / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009876:Operon; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins