呼吸代谢多样性在植物干旱适应性中的作用机制研究

Glucose-6-phosphate dehydrogenase (G6PDH) and alternative oxidase (AOX) exist commonly in plants. It has been reported that G6PDH and AOX were involved in environmental stresses. Recent findings imply that G6PDH and AOX play roles in plant resistance to drought stress. However, the mechanism of G6PDH and AOX involved in responses to drought stress remains unknown. Our recent work demonstrated that G6PDH and AOX are the main pathways in responses to drought stress. On basis of our previous works, the mechanism and relationship of G6PDH and AOX in responses to drought stress will be investigated in wheat and soybean by using physiology and biochemistry, cell biology and molecular biology methods. Furthermore, the possible cooperation mechanism of G6PDH and AOX and signaling cascade networks in resistance to drought stress will be also explored. This project is the exploration and innovation of plant responses to drought stress from the perspective of respiratory and metabolic diversity, which can uncover the role of respiratory and metabolic diversity in plant adaptation to the environment and has important theoretical significance and potential applications to the molecular mechanism of plant resistance to environmental stresses.

葡萄糖-6-磷酸脱氢酶（G6PDH）与交替氧化酶（AOX）在植物中广泛存在。G6PDH与AOX参与了植物对环境胁迫的响应。近来的研究结果显示，G6PDH和AOX均与植物抗旱性有关；然而，国内外对于G6PDH与AOX响应干旱胁迫的作用机制还未见报道。我们最近的研究结果表明，磷酸戊糖途径和AOX途径是对干旱胁迫作出响应的主要途径。因此，本项目拟在前期研究工作基础上，以小麦和大豆为材料，运用生理生化、细胞生物学和分子生物学的手段系统研究G6PDH与AOX在植物干旱适应性中的调节作用及联系，并进一步揭示G6PDH和AOX在植物干旱适应性中相互协作机制及调控的抗旱信号级联网络途径。本项目是从呼吸代谢多样性这一视角对植物响应干旱胁迫作用机制的探索和创新，为阐明呼吸代谢多样性在植物对环境的高度协调适应性中的作用提供理论依据，并对植物抗逆境分子机理的研究具有重要的理论意义和潜在的应用价值。

葡萄糖-6-磷酸脱氢酶（G6PDH）是戊糖磷酸途径限速酶，交替氧化酶（AOX）是交替途径（抗氰呼吸）末端氧化酶。有研究表明，G6PDH和AOX参与了植物对环境胁迫的响应。本项目关注的核心科学问题是G6PDH和AOX在植物干旱适应性中的作用机制及其相互协作关系。该研究利用生理生化、细胞生物学、分子生物学等方法，取得了以下主要研究成果：（1）揭示了ABA和H2O2介导的胞质G6PDH通过调节抗坏血酸-谷胱甘肽还原系统来维持体内的氧化还原平衡，从而增强植物对干旱的适应性；（2）阐明了NO介导的AOX途径通过消耗由光合作用产生的过量还原当量来避免叶绿体活性氧的过量产生，从而增强植物对干旱的适应性；（3）揭示了G6PDH介导的硝酸还原酶依赖的NO是G6PDH和AOX在植物干旱适应性中的协作衔接点。该项目的完成揭示了G6PDH和AOX在植物干旱适应性中的作用机制，并查明了两者之间的内在协作关系，为阐明呼吸代谢多样性在植物对环境的高度协调适应性机制提供理论依据，对抗旱性农作物品种的筛选具有潜在的应用价值。