Evidence for hydrogen oxidation and metabolic plasticity in widespread deep-sea sulfur-oxidizing bacteria
Evidence for hydrogen oxidation and metabolic plasticity in widespread deep-sea sulfur-oxidizing bacteria
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DOI：
10.1073/pnas.1215340110
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发表时间：
2013-01-02
影响因子：
11.1
通讯作者：
Dick, Gregory J.
中科院分区：
文献类型：
--
作者：
Anantharaman, Karthik;Breier, John A.;Dick, Gregory J.
热液喷口是一个众所周知的能源，为深海的化学合成提供动力。最近的研究表明，微生物的化学合成也令人惊讶地遍布整个黑暗的海洋，甚至在远离喷口的地方也是一个重要的二氧化碳汇。氨和硫已被确定为这种化学合成的潜在电子供体，但它们不能完全解释在远洋水柱中测得的暗初级生产率。在这里，我们使用宏基因组和元转录组学分析表明，深海人口的SUP 05组的未培养的硫氧化Gammaproteobacteria，这是丰富的广泛和多样化的海洋环境，包含和高度表达的基因编码组1镍，铁氢化酶的H-2氧化。在热液羽流和加州湾的深沃茨中，两个共存的SUP 05种群的近完整基因组的重建使详细的种群特异性元转录组学分析成为可能，揭示了基因内容和转录丰度的动态模式。涉及H-2和硫氧化的基因的SUP 05转录本在这些电子供体富集的热液羽流中最丰富。相比之下，第二个氢化酶在背景深海样品中有更丰富的转录本。再加上生物能模型的结果表明，H-2氧化可以显着贡献的SUP 05能源预算，这些发现揭示了H-2作为一个关键的能源在深海的潜在重要性。这项研究还强调了SUP 05的基因组可塑性，这使得这个广泛分布的群体能够根据当地的地球化学条件优化其能量代谢（电子供体和受体）。
Hydrothermal vents are a well-known source of energy that powers chemosynthesis in the deep sea. Recent work suggests that microbial chemosynthesis is also surprisingly pervasive throughout the dark oceans, serving as a significant CO2 sink even at sites far removed from vents. Ammonia and sulfur have been identified as potential electron donors for this chemosynthesis, but they do not fully account for measured rates of dark primary production in the pelagic water column. Here we use metagenomic and metatranscriptomic analyses to show that deep-sea populations of the SUP05 group of uncultured sulfur-oxidizing Gammaproteobacteria, which are abundant in widespread and diverse marine environments, contain and highly express genes encoding group 1 Ni, Fe hydrogenase enzymes for H-2 oxidation. Reconstruction of near-complete genomes of two cooccurring SUP05 populations in hydrothermal plumes and deep waters of the Gulf of California enabled detailed population-specific metatranscriptomic analyses, revealing dynamic patterns of gene content and transcript abundance. SUP05 transcripts for genes involved in H-2 and sulfur oxidation are most abundant in hydrothermal plumes where these electron donors are enriched. In contrast, a second hydrogenase has more abundant transcripts in background deep-sea samples. Coupled with results from a bioenergetic model that suggest that H-2 oxidation can contribute significantly to the SUP05 energy budget, these findings reveal the potential importance of H-2 as a key energy source in the deep ocean. This study also highlights the genomic plasticity of SUP05, which enables this widely distributed group to optimize its energymetabolism (electron donor and acceptor) to local geochemical conditions.