Adhikari Ashna, Park Sang-Wook
Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
Plants (Basel). 2023 Nov 1;12(21):3745. doi: 10.3390/plants12213745.
12-oxo-phytodienoic acid (OPDA) is a primary precursor of jasmonates, able to trigger autonomous signaling cascades that activate and fine-tune plant defense responses, as well as growth and development. However, its mechanism of actions remains largely elusive. Here we describe a dual-function messenger of OPDA signaling, reduced glutathione (GSH), that cross-regulates photosynthesis machinery and stress protection/adaptation in concert, optimizing plant plasticity and survival potential. Under stress conditions, the rapid induction of OPDA production stimulates GSH accumulation in the chloroplasts, and in turn leads to protein S-glutathionylation in modulating the structure and function of redox-sensitive enzymes such as 2-cysteine (Cys) peroxiredoxin A (2CPA), a recycler in the water-water cycle. GSH exchanges thiol-disulfides with the resolving Cys, while donating an electron (e, H) to the peroxidatic Cys, of 2CPA, which revives its reductase activity and fosters peroxide detoxification in photosynthesis. The electron flow protects photosynthetic processes (decreased total non-photochemical quenching, NPQ) and maintains its efficiency (increased photosystem II quantum yield, Φ). On the other hand, GSH also prompts retrograde signaling from the chloroplasts to the nucleus in adjusting OPDA-responsive gene expressions such as () and , and actuating defense responses against various ecological constraints such as salinity, excess oxidants and light, as well as mechanical wounding. We thus propose that OPDA regulates a unique metabolic switch that interfaces light and defense signaling, where it links cellular and environmental cues to a multitude of plant physiological, e.g., growth, development, recovery, and acclimation, processes.
12-氧代植物二烯酸（OPDA）是茉莉酸的主要前体，能够触发自主信号级联反应，激活并微调植物的防御反应以及生长和发育。然而，其作用机制在很大程度上仍然难以捉摸。在这里，我们描述了一种OPDA信号的双功能信使，即还原型谷胱甘肽（GSH），它协同交叉调节光合作用机制和胁迫保护/适应，优化植物的可塑性和生存潜力。在胁迫条件下，OPDA产生的快速诱导刺激叶绿体中GSH的积累，进而导致蛋白质S-谷胱甘肽化，从而调节氧化还原敏感酶如2-半胱氨酸（Cys）过氧化物酶A（2CPA）的结构和功能，2CPA是水-水循环中的一种循环剂。GSH与2CPA的解离Cys交换硫醇-二硫键，同时向其过氧化物酶Cys提供一个电子（e，H），从而恢复其还原酶活性并促进光合作用中的过氧化物解毒。电子流保护光合过程（总非光化学猝灭，NPQ降低）并维持其效率（光系统II量子产率，Φ增加）。另一方面，GSH还促使从叶绿体到细胞核的逆行信号传导，以调节OPDA响应基因的表达，如（）和，并启动针对各种生态胁迫的防御反应，如盐度、过量氧化剂和光照以及机械损伤。因此，我们提出OPDA调节一个独特的代谢开关，该开关连接光和防御信号，将细胞和环境线索与多种植物生理过程（如生长、发育、恢复和适应）联系起来。
