State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu Province 210008, China.
School of Food and Bioengineering, Zhengzhou University of Light Industry, Zhengzhou, Henan Province 450002, China.
Nat Commun. 2016 Jun 1;7:11728. doi: 10.1038/ncomms11728.
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.
土壤是一种强大的温室气体甲烷的生物汇，其在大气中的浓度极低，约为 1.84 皮克每立方米。长期以来，人们一直认为尚未培养的甲烷消耗细菌是造成这种“高亲和力”甲烷氧化（HAMO）的原因。在这里，我们展示了一种源自稻田中传统甲烷营养菌的新兴 HAMO 活性。在低亲和力氧化高浓度甲烷的过程中，HAMO 活性很快被诱导出来。在 2 周内，活性逐渐丧失，但通过用高浓度甲烷冲洗土壤，可以反复获得活性。HAMO 活性的诱导仅在甲烷营养菌种群快速生长后发生，并且宏转录组关联研究表明，同时进行的高亲和力和低亲和力甲烷氧化是由已知的甲烷营养菌催化的，而不是由先前提出的大气甲烷氧化菌催化的。这些结果为周期性排水的生态系统中大气甲烷的吸收提供了证据，这些生态系统通常被认为是大气甲烷的来源。
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