在高光等胁迫条件下，蓝藻NADPH脱氢酶(NDH-1)复合体介导的环式电子流(NDH-CEF)途径扮演着极其重要的生理角色，甚至决定着蓝藻细胞的存活，但这一途径的分子调控机理及其在蓝藻抵御高光等胁迫中的作用机理尚不了解。我们最近的初步研究结果表明，NdhO的含量与NDH-CEF活性、NDH-1复合体组装效率均呈负相关。因此，本项目将首先揭示NdhO对NDH-CEF途径的负调控机理,并进一步阐明这一途径在抵御高光胁迫中的作用机理。最后，通过分子生物学、生理和生化等手段，筛选、分离和鉴定出新的调控因子，最终达到完善NDH-CEF途径的分子调控机理，并构建一个相对完善的NDH-CEF调控网络的目的。这些功能机理的揭示将增进人们对环境胁迫条件下蓝藻NDH-CEF重要生理功能的理解，为理解高等植物NDH-CEF在胁迫条件下的生理功能提供重要的理论参考。

Although cyanobacterial NADPH dehydrogenase (NDH-1) complex-dependent cyclic electron flow around photosystem I (NDH-CEF) pathway plays an extremely important physiological role under high light conditions, and may even cause death, little is unknown regarding the functional mechanism how the NDH-CEF pathway resists high light stress. Recently, our preliminary results indicated that the amount of NdhO negatively correlates with the activity of NDH-CEF and the assembly efficiency of NDH-1 complex. Thus, we first investigated the molecular mechanism how NdhO negatively regulates NDH-CEF in the cyanobacterium Synechocystis sp. strain PCC 6803. Further, we clarified the action mechanism of NDH-CEF during high light resistance. Finally, to improve the molecular mechanism of NDH-CEF and construct a relatively improved network diagram for the NDH-CEF regulation, we screened, isolated, and identified these novel regulatory factors by using the strategies of molecular biology, physiology and biochemistry. The discovery of these functional mechanisms will certainly increase our understanding the important physiological role of cyanobacterial NDH-CEF pathway under environmental stress conditions, and provide an important theory reference for understanding the physiological function of NDH-CEF in higher plants under stressful conditions.