Yadav Ranay Mohan, Marriboina Sureshbabu, Zamal Mohammad Yusuf, Pandey Jayendra, Subramanyam Rajagopal
Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, India.
Front Plant Sci. 2023 Jul 7;14:1198474. doi: 10.3389/fpls.2023.1198474. eCollection 2023.
Light and nutrients are essential components of photosynthesis. Activating the signaling cascades is critical in starting adaptive processes in response to high light. In this study, we have used wild-type (WT), cyclic electron transport (CET) mutants like Proton Gradient Regulation (PGR) (), and to elucidate the actual role in regulation and assembly of photosynthetic pigment-protein complexes under high light. Here, we have correlated the biophysical, biochemical, and proteomic approaches to understand the targeted proteins and the organization of thylakoid pigment-protein complexes in the photoacclimation. The proteomic analysis showed that 320 proteins were significantly affected under high light compared to the control and are mainly involved in the photosynthetic electron transport chain, protein synthesis, metabolic process, glycolysis, and proteins involved in cytoskeleton assembly. Additionally, we observed that the cytochrome () expression is increased in the mutant to regulate proton motive force and ATPase across the thylakoid membrane. The increased Cyt function in could be due to the compromised function of chloroplast (cp) ATP synthase subunits for energy generation and photoprotection under high light. Moreover, our proteome data show that the photosystem subunit II (PSBS) protein isoforms (PSBS1 and PSBS2) expressed more than the Light-Harvesting Complex Stress-Related (LHCSR) protein in compared to WT and under high light. The immunoblot data shows the photosystem II proteins D1 and D2 accumulated more in and than WT under high light. In high light, CP43 and CP47 showed a reduced amount in under high light due to changes in chlorophyll and carotenoid content around the PSII protein, which coordinates as a cofactor for efficient energy transfer from the light-harvesting antenna to the photosystem core. BN-PAGE and circular dichroism studies indicate changes in macromolecular assembly and thylakoid super-complexes destacking in and due to changes in the pigment-protein complexes under high light. Based on this study, we emphasize that this is an excellent aid in understanding the role of CET mutants in thylakoid protein abundances and super-complex organization under high light.
光和营养物质是光合作用的重要组成部分。激活信号级联反应对于启动响应高光的适应性过程至关重要。在本研究中，我们使用了野生型（WT）、循环电子传递（CET）突变体，如质子梯度调节（PGR）（），以及 来阐明高光条件下光合色素 - 蛋白质复合物在调节和组装中的实际作用。在此，我们将生物物理、生化和蛋白质组学方法相结合，以了解光适应过程中靶向蛋白以及类囊体色素 - 蛋白质复合物的组织情况。蛋白质组学分析表明，与对照相比，高光条件下有320种蛋白质受到显著影响，主要参与光合电子传递链、蛋白质合成、代谢过程、糖酵解以及参与细胞骨架组装的蛋白质。此外，我们观察到在 突变体中细胞色素（） 的表达增加，以调节类囊体膜上的质子动力和ATP酶。 在 中细胞色素 功能的增加可能是由于叶绿体（cp）ATP合酶亚基在高光下能量生成和光保护功能受损所致。此外，我们的蛋白质组数据表明，在高光条件下，与野生型和 相比，光系统亚基II（PSBS）蛋白异构体（PSBS1和PSBS2）在 中的表达量高于光捕获复合体应激相关（LHCSR）蛋白。免疫印迹数据显示，在高光条件下，光系统II蛋白D1和D2在 和 中的积累量比野生型更多。在高光条件下，由于PSII蛋白周围叶绿素和类胡萝卜素含量的变化，CP43和CP47在 中的含量在高光下减少，PSII蛋白作为辅助因子协调从光捕获天线到光系统核心的有效能量转移。BN - PAGE和圆二色性研究表明，由于高光下色素 - 蛋白质复合物的变化， 和 中大分子组装和类囊体超复合体解堆叠发生了变化。基于这项研究，我们强调这对于理解CET突变体在高光下类囊体蛋白丰度和超复合体组织中的作用是一个极好的帮助。
