水稻土Fe(Ⅱ)氧化耦合NO_3^-还原的微生物变化

Shifts of microbial communities during Fe(Ⅱ) oxidation coupled to nitrate reduction in paddy soil

利用不同驯化条件(Soil、Soil+Fe(Ⅱ)、Soil+NO_3^-和Soil+Fe(Ⅱ)+NO_3^-)对华南水稻土进行中性厌氧条件下的富集培养,探究淹水期水稻土亚铁(Fe(Ⅱ))氧化和硝酸盐(NO_3^-)还原过程,及此过程中微生物群落的变化.结果表明,在Soil+Fe(Ⅱ)处理中,亚铁不能发生自然氧化.只有在Soil+Fe(Ⅱ)+NO_3^-处理中,Fe(Ⅱ)才能被氧化成Fe(Ⅲ);同时,Fe(Ⅱ)的存在减慢了NO_3^-的还原.利用高通量测序技术表征微生物群落组成随培养时间的变化,结果表明,Soil+Fe(Ⅱ)和Soil处理的微生物群落组成没有显著差异.在Soil+NO_3^-处理中,Pseudogulbenkiania、Flavobacterium和Rhodocyclus属成为优势菌群.在Soil+Fe(Ⅱ)+NO_3^-处理中,Zoogloea、Geothrix、Sunxiuqinia和Vulcanibacillus等属成为优势菌群,主要包括硝酸盐还原菌、Fe(Ⅱ)氧化菌和Fe(Ⅲ)还原菌.

A paddy soil which was collected from South China was cultivated in different treatments(Soil,Soil+Fe(II),Soil+NO3-and Soil+Fe(II)+NO3-)at circumneutral pH under anoxic conditions.The objectives were to investigate thetransformations of Fe(II)and nitrate as well as the shifts of composition and diversity of microbial communities duringthese processes.The results revealed that Fe(II)could not be oxidized in the treatment of Soil+Fe(II),but only be oxidizedin the treatment of Soil+Fe(II)+NO3-.Meanwhile,the presence of Fe(II)slowed down the NO3-reduction.Illumina highthroughput sequencing was used to profile the diversity and abundance of microbial communities over time.The resultsshowed that no significant difference of microbial communities between treatments of Soil+Fe(II)and Soil.Pseudogulbenkiania,Flavobacterium and Rhodocyclus gradually became the dominant genera in the treatment ofSoil+NO3-.Zoogloea,Geothrix,Sunxiuqinia and Vulcanibacillus were the most abundant genera in the treatment ofSoil+Fe(II)+NO3-,which was a mixture of nitrate reducers,Fe(II)oxidizers and Fe(III)reducers.