Chloroplast ROS and stress signaling

• Published in: Plant communications 2022-01, Vol.3 (1), p.100264-100264, Article 100264
• Main Authors: Li, Mengping, Kim, Chanhong
• Format: Article
• Language: English
• Subjects: 1O2; Arabidopsis - genetics; Arabidopsis - metabolism; Chloroplasts - genetics; Chloroplasts - metabolism; H2O2; operational retrograde signaling; oxidation; Oxidation-Reduction; proteostasis; Reactive Oxygen Species - metabolism; Review; ROS; Signal Transduction
• ISSN: 2590-3462; 2590-3462
• DOI: 10.1016/j.xplc.2021.100264

Chloroplasts overproduce reactive oxygen species (ROS) under unfavorable environmental conditions, and these ROS are implicated in both signaling and oxidative damage. There is mounting evidence for their roles in translating environmental fluctuations into distinct physiological responses, but their targets, signaling cascades, and mutualism and antagonism with other stress signaling cascades and within ROS signaling remain poorly understood. Great efforts made in recent years have shed new light on chloroplast ROS-directed plant stress responses, from ROS perception to plant responses, in conditional mutants of Arabidopsis thaliana or under various stress conditions. Some articles have also reported the mechanisms underlying the complexity of ROS signaling pathways, with an emphasis on spatiotemporal regulation. ROS and oxidative modification of affected target proteins appear to induce retrograde signaling pathways to maintain chloroplast protein quality control and signaling at a whole-cell level using stress hormones. This review focuses on these seemingly interconnected chloroplast-to-nucleus retrograde signaling pathways initiated by ROS and ROS-modified target molecules. We also discuss future directions in chloroplast stress research to pave the way for discovering new signaling molecules and identifying intersectional signaling components that interact in multiple chloroplast signaling pathways. Chloroplast-derived reactive oxygen species (ROS) cause oxidative damage to macromolecules. However, oxidation-/damage-associated signaling pathways and their interplay with other signaling pathways remain largely unexplored. This review focuses mainly on chloroplast-mediated signaling pathways elicited by ROS and ROS-modified target molecules and discusses their potential interplay with other known stress-related signaling pathways.