洋底深部真菌反硝化产N2新途径及原位作用模拟

真菌是洋底深部生物圈的主要真核生物，是洋底生态系统食物链的重要一环。由于对其研究起步较晚且纯培养菌株有限，人们对洋底深部真菌多样性、分布及其在驱动元素循环中的作用知之甚少。我们近期研究发现，一株栖息于洋底1.6km深的曲霉具有在厌氧条件下反硝化产N2能力，完全不同于目前已知的以N2O为终产物的真菌反硝化过程，但目前尚不清楚该菌株反硝化产N2机理，也不了解洋底深部是否存在更多的反硝化真菌及其在氮循环中的作用。本项目拟运用多维组学、基因编辑等手段，解析洋底深部曲霉的反硝化作用机理；通过检测已获得的27种69株洋底深部真菌的反硝化能力，阐明洋底深部反硝化真菌的多样性；采用模拟原位环境培养含反硝化真菌的洋底沉积物样品，探究反硝化真菌在驱动洋底深部氮循环中的作用。该项目的实施，不仅有望揭示新的反硝化真菌类群及机理，还可能诠释真菌适应洋底极端环境的新机制，从而提出真菌驱动地球氮循环的研究新方向。

Fungi are the main eukaryotes in deep subseafloor biosphere and an important part of the food chain in the subseafloor ecosystem. Due to the late start of its research and the limited pure culture strains, little is known about the diversity, distribution and the role in driving element cycle of deep subseafloor fungi. Our recent study found that a strain of Aspergillus species inhabiting at a depth of 1.6 km below seafloor has the ability to denitrify and produce N2 under anaerobic conditions, which is completely different from the currently known denitrifying process of fungi with N2O as the end product. However, the denitrification mechanism of N2 production by this strain is not clear, and whether there are more denitrifying fungi and their roles in the deep subseafloor nitrogen cycle remains unknown. This project intends to analyze the denitrification mechanism of Aspergillus sp. in deep subseafloor by means of multi-dimensional omics and gene editing technology. The diversity of denitrifying fungi in deep subseafloor was elucidated by measuring the denitrification ability of 27 deep subseafloor fungal species (69 strains). The sediment samples containing denitrifying fungi were cultured in simulated in-situ environment to investigate the role of denitrifying fungi in driving nitrogen cycle in deep subseafloor environment. The implementation of this project is expected to reveal not only new denitrifying fungi and mechanisms, but also new mechanisms for fungi to adapt to the extreme subseafloor environment, so as to propose a new direction for the study of fungi driving the nitrogen cycle in the earth.