title: Metagenomic analysis revealed highly diverse microbial arsenic metabolism genes in paddy soils with low-arsenic contents.
abstract: Microbe-mediated arsenic (As) metabolism plays a critical role in global As cycle, and As metabolism involves different types of genes encoding proteins facilitating its biotransformation and transportation processes. Here, we used metagenomic analysis based on high-throughput sequencing and constructed As metabolism protein databases to analyze As metabolism genes in five paddy soils with low-As contents. The results showed that highly diverse As metabolism genes were present in these paddy soils, with varied abundances and distribution for different types and subtypes of these genes. Arsenate reduction genes (ars) dominated in all soil samples, and significant correlation existed between the abundance of arr (arsenate respiration), aio (arsenite oxidation), and arsM (arsenite methylation) genes, indicating the co-existence and close-relation of different As resistance systems of microbes in wetland environments similar to these paddy soils after long-term evolution. Among all soil parameters, pH was an important factor controlling the distribution of As metabolism gene in five paddy soils (p = 0.018). To the best of our knowledge, this is the first study using high-throughput sequencing and metagenomics approach in characterizing As metabolism genes in the five paddy soil, showing their great potential in As biotransformation, and therefore in mitigating arsenic risk to humans.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China.
authors.forename: Ke-Qing
authors.initials: KQ
authors.lastname: Xiao
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Hong Kong, China.
authors.forename: Li-Guan
authors.initials: LG
authors.lastname: Li
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Hong Kong, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China; University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China.
authors.forename: Si-Yu
authors.initials: SY
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Bao
authors.affiliation: Environmental Biotechnology Laboratory, Department of Civil Engineering, The University of Hong Kong, Hong Kong, China. Electronic address: zhangt@hku.hk.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China. Electronic address: ygzhu@rcees.ac.cn.
authors.forename: Yong-Guan
authors.initials: YG
authors.lastname: Zhu
mesh_terms: D001149:Arsenates; D001151:Arsenic / Q000032:analysis / Q000378:metabolism*; D018053:Arsenites; D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001711:Biotransformation; D005798:Genes, Bacterial; D064351:Genes, Microbial; D006801:Humans; D008745:Methylation; D012275:Oryza; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D001149:Arsenates; D018053:Arsenites; D012987:Soil; D012989:Soil Pollutants; C015001:arsenite; D001151:Arsenic; C025657:arsenic acid
keywords: Arsenic metabolism genes; Diversity; Metagenomic analysis; Paddy soil