Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205 North Mathews Avenue, Urbana, IL, 61801, USA.
Nat Commun. 2017 Nov 15;8(1):1507. doi: 10.1038/s41467-017-01376-9.
Microbial communities drive biogeochemical cycles through networks of metabolite exchange that are structured along energetic gradients. As energy yields become limiting, these networks favor co-metabolic interactions to maximize energy disequilibria. Here we apply single-cell genomics, metagenomics, and metatranscriptomics to study bacterial populations of the abundant "microbial dark matter" phylum Marinimicrobia along defined energy gradients. We show that evolutionary diversification of major Marinimicrobia clades appears to be closely related to energy yields, with increased co-metabolic interactions in more deeply branching clades. Several of these clades appear to participate in the biogeochemical cycling of sulfur and nitrogen, filling previously unassigned niches in the ocean. Notably, two Marinimicrobia clades, occupying different energetic niches, express nitrous oxide reductase, potentially acting as a global sink for the greenhouse gas nitrous oxide.
微生物群落通过沿着能量梯度排列的代谢物交换网络驱动生物地球化学循环。随着能量产率变得有限，这些网络有利于共代谢相互作用，以最大化能量不平衡。在这里，我们应用单细胞基因组学、宏基因组学和元转录组学来研究丰富的“微生物暗物质”门 Marinimicrobia 的细菌种群，沿着明确的能量梯度进行研究。我们表明，主要 Marinimicrobia 进化分支的多样化似乎与能量产率密切相关，在分支更深的进化分支中，共代谢相互作用增加。其中一些进化分支似乎参与了硫和氮的生物地球化学循环，填补了海洋中以前未分配的生态位。值得注意的是，两个占据不同能量生态位的 Marinimicrobia 分支表达一氧化二氮还原酶，可能充当温室气体一氧化二氮的全球汇。
