基于荧光定量PCR技术分析草海沉积物中氨氧化古菌和细菌的空间分布特征

Spatial Distribution Characteristics of Ammonia-oxidizing Archaea and Ammonia-oxidizing Bacteria in Caohai Sediments Based on Fluorescence Quantitative PCR

【目的】探明贵州草海表层沉积物中氮循环微生物的丰度、群落结构及其分布规律,为研究湖泊沉积物氮循环机理和开展湖泊生态修复提供理论参考。【方法】通过实时荧光定量PCR技术测定不同季节草海表层沉积物中氨氧化古菌(AOA)与氨氧化细菌(AOB)的丰度,同时测定沉积物、间隙水及上覆水体理化因子,分析各环境因子对AOA amoA和AOB amoA的分布影响。【结果】AOA amoA和AOB amoA基因丰度分别为7.81×103~4.11×106 copies/g和3.50×10^(2)~8.11×10^(4) copies/g,amoA拷贝数在各采样区域差异显著,具有空间分布特征,湖岸带AOA amoA与AOB amoA基因丰度较低。草海沉积物中AOA/AOB为2.3~181.4。草海沉积物整体有机质含量为65.57~436.30 g/kg,总磷为3.870~5.640 g/kg,全氮为0.585~1.252 g/kg;间隙水氨氮和硝酸盐氮浓度分别为0.283~2.082 mg/L和0.007~0.060 mg/L。【结论】AOA在草海氨氧化过程发挥主要作用。AOA amoA基因丰度受有机质和总氮影响,AOB amoA基因丰度受溶解氧和总磷影响。

【Objective】The abundance,community structure and distribution rules of nitrogen cycle microorganisms in Caohai surfacial sediment of Guizhou were explored,which provided the theoretical references for studying the nitrogen cycle mechanism of lake sediments and remedying lake ecology.【Method】The abundance of ammonia-oxidizing archaea(AOA)and ammonia-oxidizing bacteria(AOB)in Caohai surfacial sediments in different seasons was determined by realtime fluorescence quantitative PCR technology.Meanwhile,the physicochemical factors in the sediments,pore water and overlying water were determined,and the effects of various environmental factors on the distribution of AOA amoA and AOB amoA were analyzed.【Result】The abundance of AOA amoA gene and AOB amoA gene was 7.81×103 copies/g–4.11×106 copies/g and 3.50×10^(2) copies/g–8.11×10^(4) copies/g.The amoA copy number varied significantly in each sampling region,showing spatial distribution characteristics.The abundance of AOA amoA and AOB amoA genes was low in the lakeshore zone.The AOA/AOB in Caohai sediments ranged from 2.3 to 181.4.In addition,the overall organic matter content,total phosphorus and total nitrogen of Caohai sediments was 65.57–436.30 g/kg,3.870–5.640 g/kg and 0.585–1.252 g/kg,respectively.The concentration of ammonia nitrogen and nitrate nitrogen in pore water were 0.283–2.082 mg/L and 0.007–0.060 mg/L,respectively.【Conclusion】AOA plays an important role in Caohai ammoxidation process.The abundance of AOA amoA gene is affected by organic matter and total nitrogen,while that of AOB amoA gene is affected by dissolved oxygen and total phosphorus.