Zhang Weipeng, Tian Ren-Mao, Sun Jin, Bougouffa Salim, Ding Wei, Cai Lin, Lan Yi, Tong Haoya, Li Yongxin, Jamieson Alan J, Bajic Vladimir B, Drazen Jeffrey C, Bartlett Douglas, Qian Pei-Yuan
Division of Life Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.
Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
mSystems. 2018 Apr 10;3(3). doi: 10.1128/mSystems.00009-18. eCollection 2018 May-Jun.
Amphipods are the dominant scavenging metazoan species in the Mariana Trench, the deepest known point in Earth's oceans. Here the gut microbiota of the amphipod Hirondellea gigas collected from the Challenger and Sirena Deeps of the Mariana Trench were investigated. The 11 amphipod individuals included for analyses were dominated by , of which a nearly complete genome was successfully recovered (designated CDP1). Compared with previously reported free-living strains, CDP1 has a highly reduced genome. Genome alignment showed deletion of the trimethylamine -oxide (TMAO) reducing gene cluster in CDP1, suggesting that the "piezolyte" function of TMAO is more important than its function in respiration, which may lead to TMAO accumulation. In terms of nutrient utilization, the bacterium retains its central carbohydrate metabolism but lacks most of the extended carbohydrate utilization pathways, suggesting the confinement of to the host gut and sequestration from more variable environmental conditions. Moreover, CDP1 contains a complete formate hydrogenlyase complex, which might be involved in energy production. The genomic analyses imply that CDP1 may have developed adaptive strategies for a lifestyle within the gut of the hadal amphipod H. gigas. As a unique but poorly investigated habitat within marine ecosystems, hadal trenches have received interest in recent years. This study explores the gut microbial composition and function in hadal amphipods, which are among the dominant carrion feeders in hadal habitats. Further analyses of a dominant strain revealed genomic features that may contribute to its adaptation to the amphipod gut environment. Our findings provide new insights into animal-associated bacteria in the hadal biosphere.
端足类动物是马里亚纳海沟（地球海洋中已知最深的地方）中占主导地位的食腐后生动物物种。在此，对从马里亚纳海沟的挑战者深渊和塞壬深渊采集的巨型深渊端足虫的肠道微生物群进行了研究。用于分析的11个端足类动物个体主要由 组成，其中成功获得了一个近乎完整的基因组（命名为CDP1）。与先前报道的自由生活菌株相比，CDP1的基因组高度简化。基因组比对显示CDP1中三甲胺氧化物（TMAO）还原基因簇缺失，这表明TMAO的“压力溶质”功能比其在呼吸中的功能更重要，这可能导致TMAO积累。在营养利用方面，该细菌保留了其核心碳水化合物代谢，但缺乏大多数扩展的碳水化合物利用途径，这表明 局限于宿主肠道并与更多可变的环境条件隔离开来。此外，CDP1包含一个完整的甲酸氢化酶复合体，这可能参与能量产生。基因组分析表明，CDP1可能已经为适应超深渊端足虫巨型深渊端足虫肠道内的生活方式而发展出了适应性策略。作为海洋生态系统中一个独特但研究较少的栖息地，超深渊海沟近年来受到了关注。本研究探索了超深渊端足类动物的肠道微生物组成和功能，它们是超深渊栖息地中占主导地位的食腐动物之一。对一个优势菌株的进一步分析揭示了可能有助于其适应端足类动物肠道环境的基因组特征。我们的发现为超深渊生物圈中与动物相关的细菌提供了新的见解。
