Deep-sea hydrothermal plumes are considered natural laboratories for understanding ecological and biogeochemical interactions. Previous studies focused on interactions between microorganisms and inorganic, reduced hydrothermal inputs including sulfur, hydrogen, iron, and manganese. However, little is known about transformations of organic compounds, especially methylated, sulfur-containing compounds, and petroleum hydrocarbons. Here, we reconstructed nine gammaproteobacterial metagenome-assembled genomes, affiliated with Methanococcales, Methylophaga, and Cycloclasticus, from three hydrothermal ecosystems. We present evidence that these three groups have high transcriptional activities of genes encoding cycling of C₁-compounds, petroleum hydrocarbons, and organic sulfur in hydrothermal plumes. This includes oxidation of methanethiol, the simplest thermochemically-derived organic sulfur, for energy metabolism in Methanococcales and Cycloclasticus. Together with active transcription of genes for thiosulfate and methane oxidation in Methanococcales, these results suggest an adaptive strategy of versatile and simultaneous use of multiple available electron donors. Meanwhile, the first near-complete MAG of hydrothermal Methylophaga aminisulfidivorans and its transcriptional profile point to active chemotaxis targeting small organic compounds. Petroleum hydrocarbon-degrading Cycloclasticus are abundant and active in plumes of oil spills as well as deep-sea vents, suggesting that they are indigenous and effectively respond to stimulus of hydrocarbons in the deep sea. These findings suggest that these three groups of Gammaproteobacteria transform organic carbon and sulfur compounds via versatile and opportunistic metabolism and modulate biogeochemistry in plumes of hydrothermal systems as well as oil spills, thus contributing broad ecological impact to the deep ocean globally.

深海热液羽流被认为是了解生态和生物地球化学相互作用的天然实验室。以前的研究集中在微生物与无机物之间的相互作用，减少了热液输入，包括硫、氢、铁和锰。然而，人们对有机化合物的转化知之甚少，尤其是甲基化的含硫化合物和石油烃。在这里，我们从三个热液生态系统中重建了九个 gammaproteobacterial 宏基因组组装的基因组，这些基因组隶属于 Methanococcales、Methylophaga和Cycloclasticus 。_{我们提供的证据表明这三个组具有编码 C 1}循环的基因的高转录活性- 热液羽流中的化合物、石油烃和有机硫。这包括甲烷硫醇的氧化，这是最简单的热化学衍生的有机硫，用于甲烷球菌和Cycloclasticus的能量代谢。连同甲烷球菌中硫代硫酸盐和甲烷氧化基因的主动转录，这些结果表明了一种多功能和同时使用多个可用电子供体的适应性策略。同时，第一个近乎完整的热液甲基噬菌体 MAG及其转录谱指向针对小有机化合物的活性趋化性。石油烃降解旋回弹在溢油羽流和深海通风口中含量丰富且活跃，这表明它们是本土的并且有效地响应深海中碳氢化合物的刺激。这些发现表明，这三组伽玛变形菌通过多种机会性代谢转化有机碳和硫化合物，并调节热液系统羽流和溢油中的生物地球化学，从而对全球深海产生广泛的生态影响。