title: The genetic basis of anoxygenic photosynthetic arsenite oxidation.
abstract: 'Photoarsenotrophy', the use of arsenite as an electron donor for anoxygenic photosynthesis, is thought to be an ancient form of phototrophy along with the photosynthetic oxidation of Fe(II), H2S, H2and NO2-. Photoarsenotrophy was recently identified from Paoha Island's (Mono Lake, CA) arsenic-rich hot springs. The genomes of several photoarsenotrophs revealed a gene cluster, arxB2AB1CD, where arxA is predicted to encode for the sole arsenite oxidase. The role of arxA in photosynthetic arsenite oxidation was confirmed by disrupting the gene in a representative photoarsenotrophic bacterium, resulting in the loss of light-dependent arsenite oxidation. In situ evidence of active photoarsenotrophic microbes was supported by arxA mRNA detection for the first time, in red-pigmented microbial mats within the hot springs of Paoha Island. This work expands on the genetics for photosynthesis coupled to new electron donors and elaborates on known mechanisms for arsenic metabolism, thereby highlighting the complexities of arsenic biogeochemical cycling.
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.
authors.forename: Jaime
authors.initials: J
authors.lastname: Hernandez-Maldonado
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Sanchez-Sedillo
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.
authors.forename: Brendon
authors.initials: B
authors.lastname: Stoneburner
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.
authors.forename: Alison
authors.initials: A
authors.lastname: Boren
authors.affiliation: US Geological Survey, 345 Middlefield Road Menlo Park, CA, 94025, USA.
authors.forename: Laurence
authors.initials: L
authors.lastname: Miller
authors.affiliation: US Geological Survey, 345 Middlefield Road Menlo Park, CA, 94025, USA.
authors.forename: Shelley
authors.initials: S
authors.lastname: McCann
authors.affiliation: US Geological Survey, 2730 N. Deer Run Road, Carson City, NV, 89701, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rosen
authors.affiliation: US Geological Survey, 345 Middlefield Road Menlo Park, CA, 94025, USA.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Oremland
authors.affiliation: Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.
authors.forename: Chad W
authors.initials: CW
authors.lastname: Saltikov
mesh_terms: D001151:Arsenic / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism*; D020587:Ectothiorhodospira / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D045482:Hot Springs / Q000382:microbiology*; D060106:Lakes / Q000382:microbiology; D008027:Light; D005810:Multigene Family / Q000235:genetics; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D018053:Arsenites; D012333:RNA, Messenger; D010088:Oxidoreductases; C078179:arsenite oxidase; C015001:arsenite; D001151:Arsenic