Conventional methanotrophs are responsible for atmospheric methane oxidation in paddy soils.
Conventional methanotrophs are responsible for atmospheric methane oxidation in paddy soils.
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传统的甲烷氧化菌是造成稻田土壤中大气甲烷氧化的原因
DOI：
10.1038/ncomms11728
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发表时间：
2016-06-01
影响因子：
16.6
通讯作者：
Jia Z
中科院分区：
文献类型：
--
作者：
Cai Y;Zheng Y;Bodelier PL;Conrad R;Jia Z
土壤是强温室气体甲烷的生物汇，大气中甲烷的浓度极低，为1.84 ppm。长期以来，尚未培养的甲烷消耗细菌被认为是这种“高亲和力”甲烷氧化（HAMO）的原因。在这里，我们显示了一个新兴的HAMO活动所产生的传统甲烷氧化菌在水稻土。高浓度甲烷的低亲和性氧化过程中迅速诱导HAMO活性。活性在2周内逐渐丧失，但可以通过用升高的甲烷冲洗土壤而反复恢复。HAMO活性的诱导只发生在甲烷氧化菌种群的快速增长之后，并且一个全元转录组关联研究表明，已知的甲烷氧化菌催化了同时发生的高亲和力和低亲和力甲烷氧化，而不是提议的新型大气甲烷氧化剂。这些结果提供了在周期性排水的生态系统中吸收大气甲烷的证据，这些生态系统通常被认为是大气甲烷的来源。 大气甲烷可以被土壤中的微生物消耗，但高亲和力甲烷氧化背后的机制仍然知之甚少。在这里，贾等人表明，已知的甲烷营养细菌是负责定期排水湿地生态系统中的大气甲烷吸收。
Soils serve as the biological sink of the potent greenhouse gas methane with exceptionally low concentrations of ∼1.84 p.p.m.v. in the atmosphere. The as-yet-uncultivated methane-consuming bacteria have long been proposed to be responsible for this ‘high-affinity' methane oxidation (HAMO). Here we show an emerging HAMO activity arising from conventional methanotrophs in paddy soil. HAMO activity was quickly induced during the low-affinity oxidation of high-concentration methane. Activity was lost gradually over 2 weeks, but could be repeatedly regained by flush-feeding the soil with elevated methane. The induction of HAMO activity occurred only after the rapid growth of methanotrophic populations, and a metatranscriptome-wide association study suggests that the concurrent high- and low-affinity methane oxidation was catalysed by known methanotrophs rather than by the proposed novel atmospheric methane oxidizers. These results provide evidence of atmospheric methane uptake in periodically drained ecosystems that are typically considered to be a source of atmospheric methane. Atmospheric methane may be consumed by microorganisms in soil, but the mechanisms behind high-affinity methane oxidization remain poorly understood. Here, Jia et al. show that known methanotrophic bacteria are responsible for atmospheric methane uptake in periodically drained wetland ecosystems.