Li Hu, Weng Bo-Sen, Huang Fu-Yi, Su Jian-Qiang, Yang Xiao-Ru
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, 361021, China.
Appl Microbiol Biotechnol. 2015 Jul;99(14):6113-23. doi: 10.1007/s00253-015-6488-2. Epub 2015 Mar 7.
Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrogen cycling. However, the effects of environmental factors on the activity, abundance, and diversity of AOA and AOB and the relative contributions of these two groups to nitrification in paddy soils are not well explained. In this study, potential nitrification activity (PNA), abundance, and diversity of amoA genes from 12 paddy soils in Southern China were determined by potential nitrification assay, quantitative PCR, and cloning. The results showed that PNA was highly variable between paddy soils, ranging from 4.05 ± 0.21 to 9.81 ± 1.09 mg NOx-N kg(-1) dry soil day(-1), and no significant correlation with soil parameters was found. The abundance of AOA was predominant over AOB, indicating that AOA may be the major members in aerobic ammonia oxidation in these paddy soils. Community compositions of AOA and AOB were highly variable among samples, but the variations were best explained by pH. AOA sequences were affiliated to the Nitrosopumilus cluster and Nitrososphaera cluster, and AOB were classified into the lineages of Nitrosospira and Nitrosomonas, with Nitrosospira being predominant over Nitrosomonas, accounting for 83.6 % of the AOB community. Moreover, the majority of Nitrosomonas was determined in neutral soils. Canonical correspondence analysis (CCA) analysis further demonstrated that AOA and AOB community structures were significantly affected by pH, soil total organic carbon, total nitrogen, and C/N ratio, suggesting that these factors exert strong effects on the distribution of AOB and AOA in paddy soils in Southern China. In conclusion, our results imply that soil pH was a key explanatory variable for both AOA and AOB community structure and nitrification activity.
氨氧化古菌（AOA）和细菌（AOB）在氮循环中发挥着重要作用。然而，环境因素对AOA和AOB的活性、丰度及多样性的影响，以及这两类菌群对稻田土壤硝化作用的相对贡献尚未得到很好的阐释。在本研究中，通过潜在硝化作用测定、定量PCR和克隆技术，对中国南方12个稻田土壤中amoA基因的潜在硝化活性（PNA）、丰度及多样性进行了测定。结果表明，稻田土壤间的PNA差异很大，范围为4.05±0.21至9.81±1.09 mg NOx-N kg(-1) 干土日(-1)，且未发现与土壤参数有显著相关性。AOA的丰度高于AOB，这表明AOA可能是这些稻田土壤好氧氨氧化的主要成员。AOA和AOB的群落组成在样本间差异很大，但这种差异最好由pH来解释。AOA序列隶属于亚硝化侏儒菌簇和亚硝化球形菌簇，AOB则被分类为亚硝化螺菌属和亚硝化单胞菌属谱系，其中亚硝化螺菌属占主导地位，占AOB群落的83.6%。此外，大多数亚硝化单胞菌存在于中性土壤中。典范对应分析（CCA）进一步表明，AOA和AOB群落结构受pH、土壤总有机碳、总氮和碳氮比的显著影响，这表明这些因素对中国南方稻田土壤中AOB和AOA的分布有强烈影响。总之，我们的结果表明土壤pH是AOA和AOB群落结构及硝化活性的关键解释变量。
