Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany.
Institute of Soil Science and Land Evaluation, Soil Biology Department, University of Hohenheim, Stuttgart, Germany.
ISME J. 2022 Jul;16(7):1788-1797. doi: 10.1038/s41396-022-01229-4. Epub 2022 Apr 6.
Soil CH fluxes are driven by CH-producing and -consuming microorganisms that determine whether soils are sources or sinks of this potent greenhouse gas. To date, a comprehensive understanding of underlying microbiome dynamics has rarely been obtained in situ. Using quantitative metatranscriptomics, we aimed to link CH-cycling microbiomes to net surface CH fluxes throughout a year in two grassland soils. CH fluxes were highly dynamic: both soils were net CH sources in autumn and winter and sinks in spring and summer, respectively. Correspondingly, methanogen mRNA abundances per gram soil correlated well with CH fluxes. Methanotroph to methanogen mRNA ratios were higher in spring and summer, when the soils acted as net CH sinks. CH uptake was associated with an increased proportion of USCα and γ pmoA and pmoA2 transcripts. We assume that methanogen transcript abundance may be useful to approximate changes in net surface CH emissions from grassland soils. High methanotroph to methanogen ratios would indicate CH sink properties. Our study links for the first time the seasonal transcriptional dynamics of CH-cycling soil microbiomes to gas fluxes in situ. It suggests mRNA transcript abundances as promising indicators of dynamic ecosystem-level processes.
土壤 CH 通量受产生和消耗 CH 的微生物驱动，这些微生物决定了土壤是这种强效温室气体的源还是汇。迄今为止，很少有在原位获得对潜在微生物组动态的全面了解。使用定量宏转录组学，我们旨在将 CH 循环微生物组与两年草地土壤中全年的净地表 CH 通量联系起来。CH 通量变化非常大：两个土壤在秋季和冬季均为净 CH 源，而在春季和夏季则为汇。相应地，每克土壤中甲烷菌 mRNA 的丰度与 CH 通量很好地相关。在春季和夏季，当土壤作为净 CH 汇时，甲烷氧化菌与甲烷菌的 mRNA 比值较高。CH 吸收与 USCα和γ pmoA 和 pmoA2 转录物的比例增加有关。我们假设甲烷菌转录物丰度可用于近似估算草地土壤的净地表 CH 排放变化。较高的甲烷氧化菌与甲烷菌的比值表明具有 CH 汇性质。我们的研究首次将 CH 循环土壤微生物组的季节性转录动态与原位气体通量联系起来。它表明 mRNA 转录物丰度是动态生态系统级过程的有前途的指标。
