基于“双原位”体系的深海偏顶蛤与内共生菌间糖相关物质传递及代谢互作过程解析

深海偏顶蛤等大型生物与化能合成菌间的共生作用是有机体获取糖等营养物质、适应冷泉热液环境并形成化能生态系统的重要机制，介导了碳等生源要素在深海的生物转化及跨圈层流动。然而受样品及解析手段等限制，对宿主与共生菌间营养物质传递与代谢互作这一共生核心过程的认知仍严重欠缺。本研究拟基于深海原位实验及组织原位分析的“双原位”研究体系，聚焦深海偏顶蛤-化能合成菌共生体形成与维持的基础物质——糖相关物质，开展其在宿主与共生菌间传递及代谢互作过程研究：通过深海原位同位素标记实验结合保真取样与组织原位质谱成像分析，筛查参与宿主与共生菌糖代谢的互作物质；利用空间转录组等单细胞分析手段，明确相关物质的合成及跨膜传递机制；基于全景代谢组和全基因组分析，探讨相关物质在共生体物质代谢及深海适应中的作用。研究将深入阐释深海共生关系中物质传递与代谢互作过程，深化对深海生物极端环境适应机制的认知，为相关工作提供全新研究范式。

The symbiosis between megafauna and chemosynthetic bacteria has been suggested as a decisive factor in the establishment and prosperity of cold seeps and hydrothermal vents ecosystem by sheltering organisms from the harsh deep-sea environments and promoting the biotransformation and global transfer of biogenic elements such as carbon. However, as the key process beneath the symbiosis, how glucose-related metabolites were transferred between host and chemosynthetic symbionts and incorporated into the downstream metabolism has remained largely unknown due to various limitations. In this study, the aforesaid question will be investigated using a self-constructed protocol in Bathymodiolinae mussels. In detail, glucose-related metabolites that potentially involved in the host-symbiont transfer and interaction will be firstly screened by MALDI-MSI analysis using samples incubated in situ with 13C labelled methane and recovered in isobaric and isothermal way. Genes involved in the synthesis and reciprocal transfer of above metabolites will be investigated subsequently using spatial transcriptome and ISH/IHC analysis. Downstream metabolites and metabolic pathways that generated from the identified glucose-related metabolites will be surveyed at last by high throughput metabolic profiling methods (GC/LC-MS, CE-MS, lipidomics and target analysis) and whole genome analysis. Collectively, the present study will provide new insights into the glucose-related metabolic interaction between Bathymodiolinae mussels and chemosynthetic symbionts as well as an updated and effective method in similar studies. The results obtained in the present study will also deepen our understanding of the deep-sea adaptation mechanism along with the biotransformation and global transfer of biogenic elements in cold seeps and hydrothermal vents.