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 m...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.展开更多
Microbial activities impact arsenic （As） transformation in mine tailings substantially, yet little is understood on the functional diversity of As metabolism genes. This study explored this issue using a metagenomic...Microbial activities impact arsenic （As） transformation in mine tailings substantially, yet little is understood on the functional diversity of As metabolism genes. This study explored this issue using a metagenomic approach coupled by a local BLASTN procedure established in our recent studies. An assembled metagenome, recovered from hypersaline and sulfidic mine tailings, was screened for As metabolism genes aioA, arrA, arsC and arsM. This was done using a local BLASTN procedure against databases of the As metabolism genes built in this study. Putative As metabolism genes detected in the assembled metagenome included 11 arsM, 20 arsC and 1 arrA full-length sequences. Together with the rRNA-based phylogenetic profiling results, a picture depicting microbial As cycling in the tailings to the genus level was obtained. It was found that most of the dominant genera in the tailings potentially harboured the genes for As reduction and/or methylation. In particular, a typical pyrite-eater present in the tailings, Thioalkalivibrio sp., was found to harbour not only arsC and arsM, but also arrA. These results highlight the unexpected diversity of As metabolism genes in the tailings, especially considering the extremely low species diversity therein. The microbial As cycling picture established here has potential use for guiding the purposeful manipulation of As biogeochemistry in the railings.展开更多
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)+3 种基金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).
文摘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.
基金financially supported by The University of Queensland Postdoctoral Fund and Mount Isa Mines, Glencore Ltd. (formerly Xstrata Copper Ltd.), Australia
文摘Microbial activities impact arsenic （As） transformation in mine tailings substantially, yet little is understood on the functional diversity of As metabolism genes. This study explored this issue using a metagenomic approach coupled by a local BLASTN procedure established in our recent studies. An assembled metagenome, recovered from hypersaline and sulfidic mine tailings, was screened for As metabolism genes aioA, arrA, arsC and arsM. This was done using a local BLASTN procedure against databases of the As metabolism genes built in this study. Putative As metabolism genes detected in the assembled metagenome included 11 arsM, 20 arsC and 1 arrA full-length sequences. Together with the rRNA-based phylogenetic profiling results, a picture depicting microbial As cycling in the tailings to the genus level was obtained. It was found that most of the dominant genera in the tailings potentially harboured the genes for As reduction and/or methylation. In particular, a typical pyrite-eater present in the tailings, Thioalkalivibrio sp., was found to harbour not only arsC and arsM, but also arrA. These results highlight the unexpected diversity of As metabolism genes in the tailings, especially considering the extremely low species diversity therein. The microbial As cycling picture established here has potential use for guiding the purposeful manipulation of As biogeochemistry in the railings.
