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Detection of a key Hg methylation gene, hgcA , in wetland soils
Author(s) -
Schaefer J. K.,
Kronberg R.M.,
Morel F. M. M.,
Skyllberg U.
Publication year - 2014
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12136
Subject(s) - swamp , wetland , temperate climate , biology , methylation , ecology , soil water , abundance (ecology) , gene , genetics
Summary The corrinoid protein, HgcA has been shown to be essential for Hg methylation in anaerobic bacteria. We investigated the diversity of hgcA from temperate and tropical wetland soils where Hg methylation is demonstrated. Sequences obtained from both environments clustered with those from the δ‐P roteobacteria , C hloroflexi and M ethanomicrobia with significant overlap in hgcA phylogeny between libraries. Clear differences in hgcA distribution were observed between two highly contrasting sites within a tropical wetland in E verglades N ational P ark, USA . hgcA sequences obtained from the northern site clustered primarily with those of methanogens, while sequences from the estuarine site clustered primarily with sulphate‐reducing bacteria and syntrophs in the δ‐P roteobacteria . Libraries obtained from soils collected from a temperate swamp in Sweden were dominated by hgcA sequences within the δ‐P roteobacteria with hgcA sequences clustering primarily with iron reducers in the upstream portion of the swamp and with sulphate reducers in the downstream portion of the swamp. Interestingly, enrichments prepared from the lower portion of this temperate wetland contained a high abundance of hgcA sequences clustering with methanogens. This first report on hgcA diversity in environmental samples suggests a role in Hg methylation for various phenotypic groups in different portions of wetlands.