蓝藻hPRP1在高光胁迫中下调光系统I的分子机制研究

Down-regulation of photosystem I (PSI) is an important mechanism for cyanobacterial cells to adapt high light conditions, but its understanding remains elusive. Recently, hPRP1 was found to interact with NDH-1 and PSI, and its absence failed to meet the down-regulation of PSI under high light conditions, thereby generating a serious high light-sensitive phenotype. This project will first reveal the physiological function of hPRP1 in conditions of high light using the methods of physiology and biochemistry. Further, we will clarify the interrelationship of hPRP1 with NDH-1-PSI supercomplex and its components NDH-1 and PSI using the methods of biochemistry and reverse genetics. Subsequently, we will reveal the molecular mechanism of PSI down-regulation during high light stresses via analyzing data of such interrelationship. Finally, we will screen, isolate and identify these novel members involved in high light-dependent down regulation of PSI using the strategies of molecular biology, physiology and biochemistry，we will reveal the molecular mechanism how they down-regulates PSI during high light stresses and we will ultimately construct a relatively improved regulatory network of high light-dependent PSI down-regulation. These achievements will certainly increase our understanding of the high light adaptation mechanism in cyanobacteria and provide an important theory reference for understanding the adaptation mechanism in higher plants.

下调光系统I（PSI）是蓝藻细胞适应高光胁迫条件的重要机制之一，但人们对它的了解尚不够。最近，我们发现了一个hPRP1与NDH-1和PSI存在蛋白互作，并且在高光胁迫中，它的缺失导致下调PSI的机制失效，出现严重的高光敏感表型。本项目拟将首先通过生理生化等手段，揭示hPRP1在高光胁迫中的重要生理功能；再通过生化和反向遗传学等技术，在高光胁迫条件下，澄清hPRP1与NDH-1-PSI，以及它的组分NDH-1和PSI之间的相互关系，从而阐明hPRP1在高光胁迫中下调PSI的分子机制；最后，通过分子生物学、生理和生化等手段，筛选、分离和鉴定出高光依赖性下调PSI的新成员，并揭示出它们在高光胁迫中下调PSI的分子机制；最终构建一个相对完善的高光依赖性下调PSI的调控网络。这些研究成果必将增进人们对蓝藻高光适应机制的理解，也为理解高等植物高光适应机制提供重要的理论参考。

下调光系统I（PSI）是蓝藻细胞适应高光胁迫条件的重要机制之一，但人们对它的了解尚不够。通过本项目的开展，我们鉴别出一个在高光下参与下调PSI的蛋白因子hPRP1，它的缺失导致下调PSI的机制失效，加剧氧化胁迫，导致严重的高光敏感表型；hPRP1的积累同时依赖于PSI和NDH-1的稳定，从而揭示了hPRP1调控PSI的分子机制。此外，我们还鉴定到另一个相关蛋白因子并对它的功能进行了探究，由此构建并完善高光依赖性下调PSI的调控网络。这一调控网络的构建必将增进人们对蓝藻适应高光胁迫的功能机制的理解，也为理解高等植物高光适应机制提供重要的理论参考。