Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA.
Sci Total Environ. 2021 Aug 1;780:146558. doi: 10.1016/j.scitotenv.2021.146558. Epub 2021 Mar 18.
The first and limiting step of nitrification is catalyzed by ammonia-oxidizing archaea (AOA) and bacteria (AOB). Recently, complete ammonia oxidizers (comammox Nitrospira) have been discovered to perform complete nitrification in one cell, yet their role in soil nitrification is still unclear. This study investigated the abundance and contribution of aerobic ammonia oxidizers in typical soil habitats, and assessed the role of comammox Nitrospira in ammonia-oxidizing communities. The results showed that comammox Nitrospira were dominant in 70% of the samples and their abundance displayed a significant positive correlation with nitrification potential. The median amoA gene transcription level of comammox Nitrospira exceeded that of AOA and AOB in in-situ soils. The abundance of comammox Nitrospira was negatively correlated with soil pH, dominating in 84% of soil samples with pH < 6.17. The results challenge the role of AOA and AOB in soils, highlighting the importance of comammox Nitrospira in soil nitrification, especially in acid soils. This work supports better understanding and regulation of the soil nitrogen cycle.
硝化作用的第一步和限速步骤是由氨氧化古菌（AOA）和细菌（AOB）催化的。最近，人们发现完全氨氧化菌（comammox Nitrospira）能够在一个细胞中完成完全硝化作用，但它们在土壤硝化作用中的作用仍不清楚。本研究调查了典型土壤生境中好氧氨氧化菌的丰度和贡献，并评估了 comammox Nitrospira 在氨氧化群落中的作用。结果表明，comammox Nitrospira 在 70%的样本中占优势，其丰度与硝化潜能呈显著正相关。原位土壤中 comammox Nitrospira 的 amoA 基因转录水平中位数超过了 AOA 和 AOB。comammox Nitrospira 的丰度与土壤 pH 呈负相关，在 pH<6.17 的土壤样本中占 84%。这些结果挑战了 AOA 和 AOB 在土壤中的作用，强调了 comammox Nitrospira 在土壤硝化作用中的重要性，尤其是在酸性土壤中。这项工作有助于更好地理解和调控土壤氮循环。
