Ore Genesis Research Unit, Project Team for Development of New-generation Research Protocol for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa 237-0061, Japan.
Research and Development Center for Submarine Resources, JAMSTEC, Yokosuka, Kanagawa 237-0061, Japan.
Environ Microbiol. 2018 Feb;20(2):862-877. doi: 10.1111/1462-2920.14032. Epub 2018 Jan 10.
Deep-sea massive sulfide deposits remaining after ceasing of hydrothermal activity potentially provide energy for a chemosynthetic ecosystem in the dark, cold marine environments. Although yet-uncultivated bacteria in the phylum Nitrospirae and the class Deltaproteobacteria are known to dominate the microbial communities of sulfide deposits at and below the seafloor, their metabolic capabilities remain largely elusive. Here, we reveal the metabolic potential of these yet-uncultivated bacteria in hydrothermally inactive sulfide deposits collected at the Southern Mariana Trough by seafloor drilling. Near-complete genomes of the predominant bacterial members were recovered from shotgun metagenomic sequences. The genomic capabilities for CO and N fixation suggest that these bacteria are primary producers in the microbial ecosystem. Their genomes also encode versatile chemolithotrophic energy metabolisms, such as the oxidation of H , sulfide and intermediate sulfur species including thiosulfate, all of which can be supplied by chemical reactions between seawater and metal sulfides. Notably, the presence of genes involved in thiosulfate oxidation in Nitrospirae and Deltaproteobacteria genomes is unusual. Our study strongly support the presence of a chemosynthetic ecosystem fuelled by the Earth's internal energy in the deep-sea massive sulfide deposits, and illustrates the unexpected metabolic capability of known bacterial taxonomic groups.
深海热液活动停止后留下的块状硫化物矿床，有可能为深海黑暗、寒冷环境中的化能合成生态系统提供能量。尽管在海底和海底以下的硫化物矿床中，硝化螺旋菌门（Nitrospirae）和δ变形菌纲（Deltaproteobacteria）尚未培养的细菌是微生物群落的主要优势菌，但它们的代谢能力在很大程度上仍然难以捉摸。在这里，我们通过海底钻探，揭示了在马里亚纳海槽采集的热液不活跃硫化物矿床中这些尚未培养的细菌的代谢潜力。从鸟枪法宏基因组序列中获得了主要细菌成员的近乎完整的基因组。基因组中 CO 和 N 固定的能力表明，这些细菌是微生物生态系统中的初级生产者。它们的基因组还编码了多种化能自养能量代谢途径，如 H 、硫化物和包括硫代硫酸盐在内的中间硫物种的氧化，这些都可以通过海水和金属硫化物之间的化学反应来提供。值得注意的是，硝化螺旋菌门和δ变形菌纲基因组中与硫代硫酸盐氧化相关的基因的存在是不寻常的。我们的研究强烈支持了在深海块状硫化物矿床中存在一个由地球内部能量驱动的化能合成生态系统，并说明了已知细菌分类群的出人意料的代谢能力。
