title: Abiotic and biotic factors responsible for antimonite oxidation in Agrobacterium tumefaciens GW4.
abstract: Antimonite [Sb(III)]-oxidizing bacteria can transform the toxic Sb(III) into the less toxic antimonate [Sb(V)]. Recently, the cytoplasmic Sb(III)-oxidase AnoA and the periplasmic arsenite [As(III)] oxidase AioAB were shown to responsible for bacterial Sb(III) oxidation, however, disruption of each gene only partially decreased Sb(III) oxidation efficiency. This study showed that in Agrobacterium tumefaciens GW4, Sb(III) induced cellular H2O2content and H2O2degradation gene katA. Gene knock-out/complementation of katA, anoA, aioA and anoA/aioA and Sb(III) oxidation and growth experiments showed that katA, anoA and aioA were essential for Sb(III) oxidation and resistance and katA was also essential for H2O2resistance. Furthermore, linear correlations were observed between cellular H2O2and Sb(V) content in vivo and chemical H2O2and Sb(V) content in vitro (R2= 0.93 and 0.94, respectively). These results indicate that besides the biotic factors, the cellular H2O2induced by Sb(III) also catalyzes bacterial Sb(III) oxidation as an abiotic oxidant. The data reveal a novel mechanism that bacterial Sb(III) oxidation is associated with abiotic (cellular H2O2) and biotic (AnoA and AioAB) factors and Sb(III) oxidation process consumes cellular H2O2which contributes to microbial detoxification of both Sb(III) and cellular H2O2.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Jingxin
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Birong
authors.initials: B
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Manman
authors.initials: M
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Gejiao
authors.initials: G
authors.lastname: Wang
mesh_terms: D016960:Agrobacterium tumefaciens / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D000965:Antimony / Q000378:metabolism*; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism
chemical_list: C061374:antimonite; D000965:Antimony; D006861:Hydrogen Peroxide; D010544:Peroxidases