Arsenic methylation and microbial communities in paddy soils under alternating anoxic and oxic conditions  

作　　者：Jing Liu Rui Pei Runzeng Liu Chuanyong Jing Wenjing Liu 

机构地区：[1]Shandong Key Laboratory of Environmental Processes and Health,School of Environmental Science and Engineering,Shandong University,Qingdao 266237,China [2]State Key Laboratory of Environmental Chemistry and Ecotoxicology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China

出　　处：《Journal of Environmental Sciences》2025年第2期468-475,共8页环境科学学报(英文版)

基　　金：supported by the Shandong Province Natural Science Foundation of Major Basic Research Program (No.ZR2020ZD34);the Key Projects of the National Natural Science Foundation of China (No.42230706);the National Natural Science Foundation of China (No.42307164);the China Postdoctoral Science Foundation (Nos.2023TQ0191 and 2023M732060);the Shandong Postdoctoral Science Foundation (No.SDBX2023041);and the Qingdao Postdoctoral Science Foundation (No.QDBSH20230202052).

摘　　要：Arsenic(As)methylation in soils affects the environmental behavior of As,excessive accumulation of dimethylarsenate(DMA)in rice plants leads to straighthead disease and a serious drop in crop yield.Understanding the mobility and transformation of methylated arsenic in redox-changing paddy fields is crucial for food security.Here,soils including unarsenic contaminated(N-As),low-arsenic(L-As),medium-arsenic(M-As),and high-arsenic(H-As)soils were incubated under continuous anoxic,continuous oxic,and consecutive anoxic/oxic treatments respectively,to profile arsenic methylating process and microbial species involved in the As cycle.Under anoxic-oxic(A-O)treatment,methylated arsenic was significantly increased once oxygen was introduced into the incubation system.The methylated arsenic concentrations were up to 2-24 times higher than those in anoxic(A),oxic(O),and oxic-anoxic(O-A)treatments,under which arsenic was methylated slightly and then decreased in all four As concentration soils.In fact,the most plentiful arsenite S-adenosylmethionine methyltransferase genes(arsM)contributed to the increase in As methylation.Proteobacteria(40.8%-62.4%),Firmicutes(3.5%-15.7%),and Desulfobacterota(5.3%-13.3%)were the major microorganisms related to this process.These microbial increasedmarkedly and played more important roles after oxygen was introduced,indicating that they were potential keystone microbial groups for As methylation in the alternating anoxic(flooding)and oxic(drainage)environment.The novel findings provided newinsights into the reoxidation-driven arsenic methylation processes and the model could be used for further risk estimation in periodically flooded paddy fields.

关 键 词：Arsenic methylation Anoxic-oxic Straighthead disease arsM gene Microbial community 

分 类 号：X70[环境科学与工程—环境工程]