Department of Soil Science, "Luiz de Queiroz" College of Agriculture, University of Sao Paulo, Avenida Padua Dias, 11, 13418-900 Piracicaba, SP, Brazil.
Federal University of Lavras, Department of Biology, Lavras, Brazil.
Microbiol Res. 2022 Dec;265:127178. doi: 10.1016/j.micres.2022.127178. Epub 2022 Sep 1.
Amazonian forest conversion into agricultural and livestock areas is considered one of the activities that contribute most to the emission of greenhouse gases, including methane. Biogenic methane production is mainly performed by methanogenic Archaea, which underscores the importance of understanding the drivers shaping microbial communities involved in the methane cycling and changes in methane metabolism. Here, we aimed to investigate the composition and structure of bacterial and archaeal communities in tropical soils in response to land-use changes, emphasizing the methanogenic communities. We collected soil samples from primary forest, pasture, and secondary forest of the Amazonian region and used a strategy based on the enrichment of the methanogenic community with three different methanogenic substrates followed by measurements of methane emission, quantification of mcrA gene copies by qPCR, and total 16 S rRNA gene sequencing (metataxonomics). We observed variations in the structure of bacterial and archaeal communities of soils under different uses. The richness of methanogenic communities was higher in pasture than forest soils and this richness remained during the incubation period, and as a consequence, the enrichment induced earlier methane emission in pastures-derived samples. Furthermore, pastures enrichments exhibited methanogenic archaea networks more complex than primary and secondary forests. In conclusion, pastures harbor a richer and more responsive methanogenic community than forest samples, suggesting that conversion of forest areas to pasture may boost methane emission.
亚马逊森林转化为农业和畜牧业用地被认为是导致温室气体排放（包括甲烷）的主要活动之一。生物成因的甲烷产生主要由产甲烷古菌完成，这突显了理解塑造参与甲烷循环和甲烷代谢变化的微生物群落的驱动因素的重要性。在这里，我们旨在研究热带土壤中细菌和古菌群落对土地利用变化的响应，重点研究产甲烷菌群落。我们从亚马逊地区的原始森林、牧场和次生林收集了土壤样本，并采用了一种基于三种不同产甲烷底物富集产甲烷群落的策略，然后测量甲烷排放、通过 qPCR 定量 mcrA 基因拷贝数，并进行 16S rRNA 基因测序（代谢组学）。我们观察到不同用途土壤中细菌和古菌群落结构的变化。牧场土壤中产甲烷菌群落的丰富度高于森林土壤，并且这种丰富度在培养期间保持不变，因此，在牧草地样本中，富集诱导更早的甲烷排放。此外，牧草地的富集显示出比原始林和次生林更复杂的产甲烷古菌网络。总之，牧场比森林样本拥有更丰富和更敏感的产甲烷菌群落，这表明将森林地区转化为牧场可能会增加甲烷排放。
