“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, H2, and 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.
|Title||The genetic basis of anoxygenic photosynthetic arsenite oxidation|
|Authors||Jamie Hernandez-Maldonado, Benjamin Sanchez-Sedillo, Brendon Stoneburner, Alison Boren, Laurence G. Miller, Shelley McCann, Michael R. Rosen, Ronald S. Oremland, Chad W. Saltikov|
|Publication Subtype||Journal Article|
|Series Title||Environmental Microbiology|
|Record Source||USGS Publications Warehouse|
|USGS Organization||National Research Program - Western Branch|