Xin Guang-Yuan, Li Lu-Ping, Wang Peng-Tao, Li Xin-Yue, Han Yuan-Ji, Zhao Xiang
State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China.
Stress Biol. 2022 Dec 1;2(1):50. doi: 10.1007/s44154-022-00066-x.
To cope with fluctuating light conditions, terrestrial plants have evolved precise regulation mechanisms to help optimize light capture and increase photosynthetic efficiency. Upon blue light-triggered autophosphorylation, activated phototropin (PHOT1 and PHOT2) photoreceptors function solely or redundantly to regulate diverse responses, including phototropism, chloroplast movement, stomatal opening, and leaf positioning and flattening in plants. These responses enhance light capture under low-light conditions and avoid photodamage under high-light conditions. NON-PHOTOTROPIC HYPOCOTYL 3 (NPH3) and ROOT PHOTOTROPISM 2 (RPT2) are signal transducers that function in the PHOT1- and PHOT2-mediated response. NPH3 is required for phototropism, leaf expansion and positioning. RPT2 regulates chloroplast accumulation as well as NPH3-mediated responses. NRL PROTEIN FOR CHLOROPLAST MOVEMENT 1 (NCH1) was recently identified as a PHOT1-interacting protein that functions redundantly with RPT2 to mediate chloroplast accumulation. The PHYTOCHROME KINASE SUBSTRATE (PKS) proteins (PKS1, PKS2, and PKS4) interact with PHOT1 and NPH3 and mediate hypocotyl phototropic bending. This review summarizes advances in phototropic growth and chloroplast movement induced by light. We also focus on how crosstalk in signaling between phototropism and chloroplast movement enhances weak light capture, providing a basis for future studies aiming to delineate the mechanism of light-trapping plants to improve light-use efficiency.
为了应对光照条件的波动，陆生植物进化出了精确的调控机制，以帮助优化光捕获并提高光合效率。在蓝光触发的自磷酸化作用下，激活的向光素（PHOT1和PHOT2）光感受器单独或冗余发挥作用，以调节多种反应，包括植物的向光性、叶绿体运动、气孔开放以及叶片定位和扁平化。这些反应在弱光条件下增强光捕获，并在强光条件下避免光损伤。非向光性下胚轴3（NPH3）和根向光性2（RPT2）是在PHOT1和PHOT2介导的反应中起作用的信号转导子。NPH3是向光性、叶片扩展和定位所必需的。RPT2调节叶绿体积累以及NPH3介导的反应。叶绿体运动的NRL蛋白1（NCH1）最近被鉴定为一种与PHOT1相互作用的蛋白，它与RPT2冗余发挥作用，介导叶绿体积累。光敏色素激酶底物（PKS）蛋白（PKS1、PKS2和PKS4）与PHOT1和NPH3相互作用，并介导下胚轴向光性弯曲。本综述总结了光诱导的向光性生长和叶绿体运动的研究进展。我们还关注向光性和叶绿体运动信号之间的相互作用如何增强弱光捕获，为未来旨在阐明植物光捕获机制以提高光利用效率的研究提供基础。
