Echeveste Medrano Maider J, Su Guangyi, Blattner Lucas A, Leão Pedro, Sánchez-Andrea Irene, Jetten Mike S M, Welte Cornelia U, Zopfi Jakob
Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University (RIBES), Nijmegen, the Netherlands.
Department of Environmental Sciences, University of Basel, Basel, Switzerland.
Environ Microbiol. 2025 Jul;27(7):e70133. doi: 10.1111/1462-2920.70133.
The greenhouse gas methane is an important contributor to global warming, with freshwater sediments representing important potential methane sources. Anaerobic methane-oxidising archaea mitigate methane release into the atmosphere by coupling the oxidation of methane to the reduction of extracellular electron acceptors or through interspecies electron transfer with microbial partners. Understanding their metabolic flexibility and microbial interactions is crucial to assess their role in global methane cycling. Here, we investigated anoxic sediments of the meromictic freshwater Lake Cadagno (Switzerland), where 'Ca. Methanoperedens' co-occur with a specific sulphate-reducing bacterium, with metagenomics and long-term incubations. Incubations were performed with different electron acceptors, revealing that manganese oxides supported highest CH oxidation potential but enriched for 'Ca. Methanoperedens' phylotypes that were hardly present in the inoculum. Combining data from the inoculum and incubations, we obtained five 'Ca. Methanoperedens' genomes, each harbouring different extracellular electron transfer pathways. In a reconstructed Desulfobacterota QYQD01 genome, we observed large multi-heme cytochromes, type IV pili, and a putative loss of hydrogenases, suggesting facultative syntrophic interactions with 'Ca. Methanoperedens'. This research deepens our understanding of the metabolic flexibility and potential interspecific interactions of 'Ca. Methanoperedens' in freshwater lakes.
温室气体甲烷是全球变暖的一个重要促成因素，淡水沉积物是重要的潜在甲烷来源。厌氧甲烷氧化古菌通过将甲烷氧化与细胞外电子受体的还原相耦合，或通过与微生物伙伴进行种间电子转移，减少甲烷向大气中的释放。了解它们的代谢灵活性和微生物相互作用对于评估它们在全球甲烷循环中的作用至关重要。在这里，我们利用宏基因组学和长期培养方法，研究了瑞士喀达诺半混合淡水湖的缺氧沉积物，其中“Ca. Methanoperedens”与一种特定的硫酸盐还原细菌共同存在。在不同电子受体存在的情况下进行培养，结果表明氧化锰支持最高的CH氧化潜力，但富集了接种物中几乎不存在的“Ca. Methanoperedens”系统发育型。结合接种物和培养的数据，我们获得了5个“Ca. Methanoperedens”基因组，每个基因组都含有不同的细胞外电子转移途径。在一个重建的脱硫杆菌QYQD01基因组中，我们观察到大型多血红素细胞色素、IV型菌毛以及推测的氢化酶缺失，这表明它与“Ca. Methanoperedens”存在兼性共生相互作用。这项研究加深了我们对淡水湖泊中“Ca. Methanoperedens”的代谢灵活性和潜在种间相互作用的理解。
