脂类介导的丛枝菌根真菌对干旱胁迫的响应及脱落酸的调控机制

丛枝菌根（AM）真菌是重要的植物根系共生真菌，能提高植物对干旱胁迫的抗性，但是AM真菌自身对干旱胁迫的响应模式尚不清楚，尤其是干旱胁迫怎样影响丛枝（AM真菌的核心结构）的形成。脂类是植物运输给AM真菌的不可或缺的营养，逆境胁迫（如低pH）能抑制根系中AM真菌特异性的脂类合成和运输，从而抑制侵染（尤其是丛枝的形成）。因此，我们推测干旱胁迫也可能通过影响脂类代谢而调控AM真菌的侵染。此外，植物胁迫响应激素ABA能促进AM真菌产孢（积累着大量脂类）。基于此，本项目拟以番茄和AM真菌建立的共生体为研究材料，探讨不同AM真菌菌种的侵染对干旱胁迫的响应，解析干旱胁迫下共生体中脂类代谢（合成和运输）的动态变化及其与侵染的关系，揭示ABA在脂类介导的AM真菌侵染响应干旱胁迫中的调控作用和机制。研究结果有助于我们从AM真菌这个新视角理解共生体应对干旱胁迫的现象和分子生理机制，从而更好地利用AM真菌提高植物对干旱胁迫的抗性。

Arbuscuar mycorrhizal (AM) fungi are important symbiotic fungi in association with plant roots, and can promote plant resistance to drought stress. However, the response patterns of AM fungi themselves to drought stress are still unclear, especially the influence of drought stress on the formation of arbuscules (the core structures of AM fungi). Lipids are the indispensable nutrition which plants transfer to AM fungi. Adverse stresses (such as low pH) can inhibit the AM fungi-specific lipid biosynthesis and the transfer to AM fungi in roots, and therefore inhibit AM fungal colonization (particularly the formation of arbuscules). Consequently, we speculate that drought stress could regulate AM fungal colonization by affecting lipid metabolism. Moreover, the stress-responsive phytohormone ABA can promote the production of spores (in which a large amount of lipids are accumulated). Based on these, this project will take the symbionts of tomato and AM fungi as research materials to investigate the responses of different AM fungal species to drought stress in terms of colonization, to dissect the dynamics of lipid metabolism (including the biosynthesis and the transfer) in the symbionts under drought stress and its relation with AM fungal colonization, and to reveal the regulation and the mechanisms by ABA in the lipid-mediated responses of AM fungal colonization to drought stress. These results will facilitate our understanding of the responses of symbionts to drought stress and the molecular physiological mechanisms from a novel view of AM fungi, and therefore benefit the better application of AM fungi in promoting plant resistance to drought stress.