稻田NO3-还原耦合As(III)氧化过程及微生物群落特征

以华南稻田土壤为研究对象通过构建微宇宙体系，研究了淹水稻田自养硝酸盐还原耦合As（III）氧化过程及其微生物群落结构组成.结果表明，NO₃^-的添加促进了稻田土壤中As（III）的氧化，在未添加NO₃^-的处理（Soil+As（III））以及灭菌处理（Sterilized soil+As（III）+NO₃^-）中As（III）未发生明显的氧化；在Soil+As（III）+NO₃^-处理中，NO₃^-有少量被还原，而在Soil+NO₃^-处理中，NO₃^-没有被还原.通过16S rRNA高通量分析在NO₃^-还原耦合As（III）氧化体系中微生物群落结构特征，在Soil+As（III）+NO₃^-处理中shannon指数相对较低为8.19，土壤微生物群落多样性降低，其中在门水平上主要优势菌群为变形菌门Proteobacteria（33%）、绿弯菌门Chloroflexi（11%）、浮霉菌门Planctomycetes（12%）；在属水平上主要的优势菌属为Gemmatimonas（7.4%）以及少量的Singulisphaera、Thermomonas、Bacillus.NO₃^-的添加能够促进稻田土壤中自养As（III）氧化，并且影响着稻田土壤中微生物群落组成.

Nitrate reduction coupled with As(III) oxidation process and community structure analysis in flooded paddy soil

Paddy soil was collected from Southern China and used as an inoculum in a microcosm experiment. The microcosm experiment was used to study the process of autotrophic nitrate reduction coupled with As(III) oxidation and its microbial community structure in the flooded paddy field. As(III) was completely oxidized in As(III)+NO₃^- treatment, while no As(III) oxidation was observed in the As(III) amendment and the sterilization treatment (Sterilized soil+As(III)+NO₃^-). Meanwhile, a small amount of NO₃^- reduction was observed in As(III)+NO₃^- amendment and no NO₃^- reduction was observed in NO₃^- amendment. 16S rRNA-based high-throughput sequencing was used to investigate the microbial community structure in Soil+As(III)+NO₃^- treatment. Diversity of soil bacterial community was decreased and its Shannon index was 8.19in Soil+As(III)+NO₃^- treatment. The dominant bacteria at the phyla level were Proteobacteria (33%), Chloroflexi (11%), and Planctomycetes (12%), and the dominant genus were Gemmatimonas (7.4%), with few Singulisphaera、Thermomonas、Bacillus in Soil+As(III)+NO₃^- treatment. In summary, the addition of NO₃^- can promote the autotrophic As(III) oxidation and influences the microbial community composition in flooded paddy soil.