The process of nitrite-dependent anaerobic methane oxidation (n-damo) catalysed by Candidatus Methylomirabilis oxyfera (M. oxyfera)-like bacteria is a novel pathway in regulating methane (CH₄) emissions from paddy fields. Nitrogen fertilization is essential to improve rice yields and soil fertility; however, its effect on the n-damo process is largely unknown. Here, the potential n-damo activity, abundance and community composition of M. oxyfera-like bacteria were investigated in paddy fields under three long-term (32 years) fertilization treatments, i.e. unfertilized control (CK), chemical fertilization (NPK) and straw incorporation with chemical fertilization (SNPK). Relative to the CK, both NPK and SNPK treatments significantly (p < 0.05) increased the potential n-damo activity (88%–110%) and the abundance (52%–105%) of M. oxyfera-like bacteria. The variation of soil organic carbon (OrgC) content and inorganic nitrogen content caused by the input of chemical fertilizers and straw returning were identified as the key factors affecting the potential n-damo activity and the abundance of M. oxyfera-like bacteria. However, the community composition and diversity of M. oxyfera-like bacteria did not change significantly by the input of fertilizers. Overall, our results provide the first evidence that long-term fertilization greatly stimulates the n-damo process, indicating its active role in controlling CH₄ emissions from paddy fields.

中文翻译：

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亚硝酸盐依赖性厌氧甲烷氧化菌的潜在活性、丰度和群落组成对水稻土长期施肥的响应

由Candidatus Methylomirabilis oxyfera ( M. oxyfera ) 样细菌催化的亚硝酸盐依赖性厌氧甲烷氧化 (n-damo) 过程是调节稻田甲烷 (CH _{4 ) 排放的新途径。}施氮肥对于提高水稻产量和土壤肥力至关重要；然而，它对 n-damo 过程的影响在很大程度上是未知的。在这里， M的潜在 n-damo 活动、丰度和群落组成。氧化酶在三种长期（32 年）施肥处理下，即不施肥对照（CK）、化学施肥（NPK）和秸秆掺入化学施肥（SNPK），对稻田中的类细菌进行了调查。相对于 CK，NPK 和 SNPK 处理均显着 ( p  < 0.05) 增加了潜在的 n-damo 活性 (88%–110%) 和M的丰度 (52%–105%) 。oxyfera类细菌。化肥投入和秸秆还田引起的土壤有机碳（OrgC）含量和无机氮含量的变化被确定为影响潜在n-damo活性和M丰度的关键因素。氧化酶-样细菌。但是，M的社区组成和多样性。oxyfera样细菌没有因施肥而发生显着变化。总的来说，我们的结果提供了长期施肥极大地刺激 n-damo 过程的第一个证据，表明它在控制稻田CH _{4排放方面的积极作用。}