Chloroplast Biogenesis in Plants Responding to Abiotic Stresses
摘要
The apparatus of the electron transport chain for photosynthesis process is made up of various protein complexes, such as photosystem II (PSII), Cytb6f, Plastocyanin (PC), Photosystem-I (PSI), and photoprotection-related proteins. These protein complexes are prone to damage due to different abiotic stresses and are continuously resynthesized to replace the damaged ones. Oxygenic photosynthesis uses sunlight, CO2, and water to produce food and oxygen for most life forms. In photosynthetic plants, chloroplasts are the primary reactive oxygen species (ROS)-producing sites, involving PSII and PSI, which hamper photosynthesis and cause photoinhibition. The plant may adjust its thylakoid membrane’s lipid content and structural configuration to more effectively dissipate excess energy (non-photochemical quenching), improve membrane fluidity, and optimize the photosynthetic process, thus preventing potential damage from abiotic stresses. Chloroplasts shift their orientation by migrating perpendicular to incident light when exposed to high light intensity. Chloroplast biogenesis and development require coordinated expression of genes encoded by the plastid and nuclear systems and are necessary for the growth of chloroplasts in higher plants. A new D1 protein is generated and placed inside PSII again after the damaged D1 protein in PSII is eliminated and broken down by specific proteases. These findings suggest that there is a specific pathway involved in chloroplast biogenesis after stress-induced damage. This insight could inform the development of more stable protein complexes of the photosynthetic electron transport chain through genetic engineering, which might increase the number of important constituents of core photosynthetic machinery, improving photosynthetic rates and helping the scientific community to better understand the mechanisms to boost photosynthetic efficiency and accelerate the stress tolerance techniques for crop improvement.