深海贻贝是深海热液和冷泉中的优势生物，共生是其适应深海独特环境的关键。深海热液区高重金属环境为研究双壳类环境适应机制提供有利的平台。由于深海样品的难获取和培养，国内外对深海贻贝重金属适应机制的研究不深入且未突出共生菌的作用。本研究以西太平洋化能生态系统中的优势种 — 平端深海偏顶蛤为研究对象，基于前期建立的深海贻贝活体取样和长期培养体系，结合室内实验和野外调查开展深海贻贝重金属适应机制的研究。室内实验基于构建的携带和非携带共生菌的深海贻贝群体，从生理、细胞、分子水平比较二者在重金属胁迫下响应规律，利用转录组测序，筛选与重金属胁迫相关的关键基因和通路；野外调查探索深海贻贝体内共生菌含量与环境重金属浓度的关系，探讨不同含量的共生菌在生理、细胞和分子水平对深海贻贝在重金属环境长期暴露下的影响，剖析共生菌的作用。本研究将从共生的角度推进对深海生物环境适应性的解析，丰富对深海特殊生命过程的认知，为深海共生体系研究提供理论基础。

Deep-sea mussels of the genus Bathymodiolus are one of the dominant macroorganisms in deep-sea ecosystems including hydrothermal vents and cold seeps. The Bathymodiolus mussels succeed reaching high biomasses in these harsh conditions thanks to chemosynthetic, carbon-fixing bacterial symbionts located in their gill tissue. Characterized by high levels of heavy metals in the vent fluids, hydrothermal fields are regarded as natural platforms to study the environmental adaption and evolution of the bivalves. However, due to the difficulties in sampling and cultivation of the deep-sea mussels, research on metal adaption of the Bathymodiolus mussels remains limited, and the roles of their symbiotic bacteria are unclear. In the present study, by combining deep-sea environmental detection and sampling, and in-door experiments, we will use the deep-sea mussel Bathymodiolus platifrons, widely distributed in the chemosynthetic ecosystems of the Western Pacific, as a toxicological model to investigate the response of deep-sea macroorganism to heavy metal toxicity and explain their adaption strategies under extreme environment. Firstly, we aim to conduct in-door experiments to systematically characterize the effects of heavy metals on the physiological, cellular and molecular levels of the symbiont-containing and symbiont-free mussels, then causal genes and pathways responsible for heavy metal resistance and stress responses will be identified through gene expression profiles. In addition, by deep-sea environmental detection and sampling, we will explain the relationship between symbiotic bacteria content and the metal levels from different sampling locations (vents and seeps), by analysis of metal accumulation, antioxidant enzyme activity, cellular structural changes, and expression of the selected genes of Bathymodiolus mussels from different locations, we will figure out the effects of the content of symbiotic bacteria on the Bathymodiolus mussels under metal exposure from physiological, cellular and molecular aspects, the roles of symbiotic bacteria will then be evaluated. This work will further reveal underlying adaption mechanisms of deep-sea mussels to metal envrionment from symbiotic aspect, enrich our knowledge of the special life process in the deep sea, and also provide model theoretical basis for the study of deep-sea endosymbiosis.