title: Mercury-methylating genes dsrB and hgcA in soils/sediments of the Three Gorges Reservoir.
abstract: Previous research found that the water-level fluctuating zone (WLFZ) of the Three Gorges Reservoir (TGR) was an Hg-sensitive area. However, little research has been conducted on the distribution of Hg-methylating microorganisms in this area. The goal of this research was to provide an initial description of the distribution of the dsrB (for sulfate-reducing bacteria) and hgcA (one gene confirmed for Hg methylation) genes. Different types of soil were selected to analyze the abundance of the dsrB and hgcA in different periods, in inundated soil (SI, ≤155 m, which becomes sediment during the wet period, SS) and in non-inundated soil (≥175 m, SN) from Shibao, a typical WLFZ of the TGR. A significant positive correlation was observed between dsrB and hgcA abundance and MeHg concentrations, suggesting that microorganisms with these genes contribute to Hg methylation. Principal component analysis (PCA) indicated that dsrB diversity was highest in SI, followed by SS; SS had the highest diversity of hcgA. Six phylogenetic trees were constructed and showed that more strains were present in SI than in SS. HgcA sequences in SS were confined to three evolutionarily distant clades, δ-Proteobacteria, a methanogen group, and a Clostridia group, which was relatively rare among most clades.
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.|Research Center of Bioenergy and Bioremediation, Southwest University, Chongqing, 400715, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Du
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.|Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing, 400715, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Ma
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.|Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing, 400715, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.|Research Center of Bioenergy and Bioremediation, Southwest University, Chongqing, 400715, China.
authors.forename: Xianzhu
authors.initials: X
authors.lastname: Dai
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.|Research Center of Bioenergy and Bioremediation, Southwest University, Chongqing, 400715, China.
authors.forename: Caiyun
authors.initials: C
authors.lastname: Yang
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China.|Research Center of Bioenergy and Bioremediation, Southwest University, Chongqing, 400715, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Luo
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China. dywang@swu.edu.cn.|Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing, 400715, China. dywang@swu.edu.cn.
authors.forename: Dingyong
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Resources and Environment, Southwest University, No. 2, Tiansheng Road, Beibei District, Chongqing, 400715, People's Republic of China. aigara@mail.ecc.u-tokyo.ac.jp.|Research Center of Bioenergy and Bioremediation, Southwest University, Chongqing, 400715, China. aigara@mail.ecc.u-tokyo.ac.jp.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D005798:Genes, Bacterial; D008628:Mercury / Q000378:metabolism*; D008745:Methylation; D010802:Phylogeny; D012987:Soil; D012988:Soil Microbiology; D012989:Soil Pollutants; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical
chemical_list: D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D014867:Water; D008628:Mercury
keywords: Mercury methylators; Soils/sediments; Water-level fluctuating zone; dsrB; hgcA