光合作用过程中，H+和带电离子的跨膜转移形成跨类囊体膜质子梯度ΔpH和跨膜电位Δψ。二者是ATP合酶驱动力，通过推动H+经ATP合酶泵出维持囊腔酸度，促进光合作用。波动光环境下，植物快速调节∆ψ大小散失过饱和光能或者减少能量损失，是进行光保护和维持光能利用效率所必需的。虽然Δψ调节对光合作用至关重要，但是参与调控的分子基础和作用机理尚不清楚。项目前期筛选到一个Δψ缺失突变体nam1，是研究Δψ调节分子机制的理想材料。本项目拟开展以下工作：(1)分析NAM1调节Δψ的光响应动力学特征；(2)利用遗传学和电生理学技术探讨NAM1与Δψ调节因子AtBest和KEA3的相关性以及对二者活性的影响，揭示NAM1调节∆ψ的分子机理；(3)构建nam1相关的∆ψ调节缺陷突变体，分析光胁迫下突变体的光合特征，阐明Δψ调节的生理学意义。本项目的研究结果将为深入研究植物调节光合作用适应自然光环境提供新观点。

Photosynthetic electron transport accompanied by accumulation of protons in the thylakoid lumen and translocation of charged ions, resulting in a charge difference across the thylakoid membrane, leading to a membrane potential (ΔΨ) and a proton concentration gradient (ΔpH). Both of them are driving force for ATP synthesis, driving the ATP synthase to pump out H+ from thylakoid lumen. Therefore, acidification of the thylakoid lumen are regulated to a certain level to promote the photosynthesis. Under fluctuating light conditions, Δψ is quickly modulated to dissipate excess light energy or prevent energy waste, which is essential for activating photoprotection and maintaining high light efficiency. Although Δψ regulation is crucial for photosynthesis, but the molecular basis and related mechanisms of Δψ regulation are still unclear. In this project, we isolated an Arabidopsis mutant nam1 with a serious defect in Δψ regulation, which is an ideal material for studying Δψ regulation. According to the problems and shortcomings in the current research, the following research objectives and strategies will be used in this work. (1) we will analyze the dynamics characteristics of Δψ regulated by NAM1 in response to various light intensity; (2) To investigate the molecular mechanism of NAM1 in regulating Δψ, we will use genetic and electrophysiology techniques to determine the correlation of NAM1 with AtBest and KEA3, and the effects on their ion transport activity; (3) To elucidate the physiological function of Δψ regulation, we will construct nam1-related mutants and determine their photosynthetic characteristics under light stress. These results will provide new insights into the molecular mechanisms of photosynthesis regulation in improving plant fitness under natural light environment.