Open AccessArsenite oxidase gene diversity among C hloroflexi and P roteobacteria from E l T atio G eyser F ield, C hile
Author(s) -
Engel Annette Summers,
Johnson Lindsey R.,
Porter Megan L.
Publication year - 2013
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/1574-6941.12030
Subject(s) - biology , arsenite , chloroflexi (class) , arsenic , firmicutes , phylogenetic diversity , phylogenetic tree , gene , arsenate , proteobacteria , genetics , 16s ribosomal rna , ecology , materials science , metallurgy
Arsenic concentrations (450–600 μmol L −1 ) at the E l T atio G eyser F ield in northern C hile are an order of magnitude greater than at other natural geothermal sites, making E l T atio an ideal location to investigate unique microbial diversity and metabolisms associated with the arsenic cycle in low sulfide, > 50 °C, and circumneutral p H waters. 16 S r RNA gene and arsenite oxidase gene ( aio A ) diversities were evaluated from biofilms and microbial mats from two geyser‐discharge stream transects. Chloroflexi was the most prevalent bacterial phylum at flow distances where arsenite was converted to arsenate, corresponding to roughly 60 °C. Among aio A ‐like gene sequences retrieved, most had homology to whole genomes of C hloroflexus aurantiacus , but others were homologous to alphaproteobacterial and undifferentiated beta‐ and gammaproteobacterial groups. No D einococci , T hermus , A quificales , or C hlorobi aio A ‐like genes were retrieved. The functional importance of amino acid sites was evaluated from evolutionary trace analyses of all retrieved aio A genes. Fifteen conserved residue sites identified across all phylogenetic groups highlight a conserved functional core, while six divergent sites demonstrate potential differences in electron transfer modes. This research expands the known distribution and diversity of arsenite oxidation in natural geothermal settings, and provides information about the evolutionary history of microbe–arsenic interactions.