Calcium carbonate(CaCO_3) application is widely used to ameliorate soil acidification. To counteract soil and bacterial community response to CaCO_3 application in an acidic paddy soil in southern China, a field exper...Calcium carbonate(CaCO_3) application is widely used to ameliorate soil acidification. To counteract soil and bacterial community response to CaCO_3 application in an acidic paddy soil in southern China, a field experiment was conducted with four different dosages of CaCO_3 addition, 0, 2.25, 4.5 and 7.5 tons/ha, respectively. After one seasonal growth of rice, soil physicochemical properties, soil respiration and bacterial communities were investigated. Results showed that soil p H increased accordingly with increasing dose of CaCO_3 addition, and 7.5 tons/ha addition increased soil p H to neutral condition. Moderate dose of CaCO_3 application(4.5 tons/ha) significantly increased soil dissolved organic carbon(DOC) and dissolved organic nitrogen(DON) content, enhanced soil respiration, while the excessive CaCO_3 application(7.5 tons/ha) decreased these soil properties. High-throughput sequencing results illustrated that moderate dose of CaCO_3 application increased the richness and alpha diversity of soil bacterial community. Compared with control, the relative abundance of Anaerolineaceae family belonging to Chloroflexi phylum increased by 38.7%, 35.4% and 24.5% under 2.25, 4.5 and 7.5 tons/ha treatments, respectively.Redundancy analysis(RDA) showed that soil p H was the most important factor shaping soil bacterial community. The results of this study suggest that proper dose of CaCO_3 additions to acid paddy soil in southern China could have positive effects on soil properties and bacterial community.展开更多
Paddy soils are potential hotspots of combined contamination with arsenic(As) and antibiotics, which may induce co-selection of antibiotic resistance genes(ARGs) and As biotransformation genes (ABGs), resulting in dis...Paddy soils are potential hotspots of combined contamination with arsenic(As) and antibiotics, which may induce co-selection of antibiotic resistance genes(ARGs) and As biotransformation genes (ABGs), resulting in dissemination of antimicrobial resistance and modification in As biogeochemical cycling. So far, little information is available for these coselection processes and specific patterns between ABGs and ARGs in paddy soils. Here, the16S rRNA amplicon sequencing and high-throughput quantitative PCR and network analysis were employed to investigate the dynamic response of ABGs and ARGs to As stress and manure application. The results showed that As stress increased the abundance of ARGs and mobile genetic elements (MGEs), resulting in dissemination risk of antimicrobial resistance. Manure amendment increased the abundance of ABGs, enhanced As mobilization and methylation in paddy soil, posing risk to food safety. The frequency of the co-occurrence between ABGs and ARGs, the host bacteria carrying both ARGs and ABGs were increased by As or manure treatment, and remarkably boosted in soils amended with both As and manure. Multidrug resistance genes were found to have the preference to be co-selected with ABGs, which was one of the dominant co-occurring ARGs in all treatments, and manure amendment increased the frequency of Macrolide-Lincosamide-Streptogramin B resistance(MLSB) to co-occur with ABGs. Bacillus and Clostridium of Firmicutes are the dominant host bacteria carrying both ABGs and ARGs in paddy soils. This study would extend our understanding on the co-selection between genes for antibiotics and metals, also unveil the hidden environmental effects of combined pollution.展开更多
Electrotrophs are microbes that can receive electrons directly from cathode in a microbial electrolysis cell(MEC).They not only participate in organic biosynthesis,but also be crucial in cathode-based bioremediation.H...Electrotrophs are microbes that can receive electrons directly from cathode in a microbial electrolysis cell(MEC).They not only participate in organic biosynthesis,but also be crucial in cathode-based bioremediation.However,little is known about the electrotrophic community in paddy soils.Here,the putative electrotrophs were enriched by cathodes of MECs constructed from five paddy soils with various properties using bicarbonate as an electron acceptor,and identified by 16S rRNA-gene based Illumina sequencing.The electrons were gradually consumed on the cathodes,and 25%–45% of which were recovered to reduce bicarbonate to acetic acid during MEC operation.Firmicutes was the dominant bacterial phylum on the cathodes,and Bacillus genus within this phylum was greatly enriched and was the most abundant population among the detected putative electrotrophs for almost all soils.Furthermore,several other members of Firmicutes and Proteobacteria may also participate in electrotrophic process in different soils.Soil pH,amorphous iron and electrical conductivity significantly influenced the putative electrotrophic bacterial community,which explained about 33.5% of the community structural variation.This study provides a basis for understanding the microbial diversity of putative electrotrophs in paddy soils,and highlights the importance of soil properties in shaping the community of putative electrotrophs.展开更多
基金supported by the Special Fund for AgroScientific Research in the Public Interest(No.201403015)the National Natural Science Foundation of China(No.21677157)the National Key Research and Development Program(Nos.2017YFD0801502 and 2018YFD0800202)
文摘Calcium carbonate(CaCO_3) application is widely used to ameliorate soil acidification. To counteract soil and bacterial community response to CaCO_3 application in an acidic paddy soil in southern China, a field experiment was conducted with four different dosages of CaCO_3 addition, 0, 2.25, 4.5 and 7.5 tons/ha, respectively. After one seasonal growth of rice, soil physicochemical properties, soil respiration and bacterial communities were investigated. Results showed that soil p H increased accordingly with increasing dose of CaCO_3 addition, and 7.5 tons/ha addition increased soil p H to neutral condition. Moderate dose of CaCO_3 application(4.5 tons/ha) significantly increased soil dissolved organic carbon(DOC) and dissolved organic nitrogen(DON) content, enhanced soil respiration, while the excessive CaCO_3 application(7.5 tons/ha) decreased these soil properties. High-throughput sequencing results illustrated that moderate dose of CaCO_3 application increased the richness and alpha diversity of soil bacterial community. Compared with control, the relative abundance of Anaerolineaceae family belonging to Chloroflexi phylum increased by 38.7%, 35.4% and 24.5% under 2.25, 4.5 and 7.5 tons/ha treatments, respectively.Redundancy analysis(RDA) showed that soil p H was the most important factor shaping soil bacterial community. The results of this study suggest that proper dose of CaCO_3 additions to acid paddy soil in southern China could have positive effects on soil properties and bacterial community.
基金supported by the National Natural Science Foundation of China (Nos. 41991332, 41977323 and 42090063)。
文摘Paddy soils are potential hotspots of combined contamination with arsenic(As) and antibiotics, which may induce co-selection of antibiotic resistance genes(ARGs) and As biotransformation genes (ABGs), resulting in dissemination of antimicrobial resistance and modification in As biogeochemical cycling. So far, little information is available for these coselection processes and specific patterns between ABGs and ARGs in paddy soils. Here, the16S rRNA amplicon sequencing and high-throughput quantitative PCR and network analysis were employed to investigate the dynamic response of ABGs and ARGs to As stress and manure application. The results showed that As stress increased the abundance of ARGs and mobile genetic elements (MGEs), resulting in dissemination risk of antimicrobial resistance. Manure amendment increased the abundance of ABGs, enhanced As mobilization and methylation in paddy soil, posing risk to food safety. The frequency of the co-occurrence between ABGs and ARGs, the host bacteria carrying both ARGs and ABGs were increased by As or manure treatment, and remarkably boosted in soils amended with both As and manure. Multidrug resistance genes were found to have the preference to be co-selected with ABGs, which was one of the dominant co-occurring ARGs in all treatments, and manure amendment increased the frequency of Macrolide-Lincosamide-Streptogramin B resistance(MLSB) to co-occur with ABGs. Bacillus and Clostridium of Firmicutes are the dominant host bacteria carrying both ABGs and ARGs in paddy soils. This study would extend our understanding on the co-selection between genes for antibiotics and metals, also unveil the hidden environmental effects of combined pollution.
基金supported by the National Natural Science Foundation of China(Nos.41430858 and 41601242)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDB15020201 and XDB15020302)the National Key Research and Development Program(No.2017YFD0801502)
文摘Electrotrophs are microbes that can receive electrons directly from cathode in a microbial electrolysis cell(MEC).They not only participate in organic biosynthesis,but also be crucial in cathode-based bioremediation.However,little is known about the electrotrophic community in paddy soils.Here,the putative electrotrophs were enriched by cathodes of MECs constructed from five paddy soils with various properties using bicarbonate as an electron acceptor,and identified by 16S rRNA-gene based Illumina sequencing.The electrons were gradually consumed on the cathodes,and 25%–45% of which were recovered to reduce bicarbonate to acetic acid during MEC operation.Firmicutes was the dominant bacterial phylum on the cathodes,and Bacillus genus within this phylum was greatly enriched and was the most abundant population among the detected putative electrotrophs for almost all soils.Furthermore,several other members of Firmicutes and Proteobacteria may also participate in electrotrophic process in different soils.Soil pH,amorphous iron and electrical conductivity significantly influenced the putative electrotrophic bacterial community,which explained about 33.5% of the community structural variation.This study provides a basis for understanding the microbial diversity of putative electrotrophs in paddy soils,and highlights the importance of soil properties in shaping the community of putative electrotrophs.
