Chanhong Kim is a Principal Investigator at the Center for Excellence in Molecular Plant Sciences (CEMPS), Chinese Academy of Sciences (CAS) (www.cemps.ac.cn) with a distinguished international research career in molecular plant sciences, focusing on chloroplast-mediated retrograde signaling and plant stress responses. With prior positions at ETH Zurich and Cornell University, his research uncovers how chloroplasts detect environmental cues and initiate stress signaling to the nucleus, contributing to cellular homeostasis and stress adaptation. His group has elucidated the roles of ROS, tryptophan oxidation, and hormone interactions in these pathways, and recently identified key chloroplast thermosensors linked to plant thermal tolerance.

Abstract of the talk: Chloroplasts are both the primary sites of photosynthesis and major sources of reactive oxygen species (ROS) in plant cells. Under fluctuating environmental conditions, ROS-mediated oxidative modifications of chloroplast macromolecules, particularly photosynthetic proteins, play a dual role in cellular stress responses. While excessive oxidation leads to photodamage and protein degradation, moderate levels of oxidative modifications serve as regulatory switches that influence protein function, repair, and homeostasis. Recent studies highlight how these modifications impact protein turnover, quality control mechanisms, and retrograde signaling pathways that communicate chloroplast status to the nucleus. Understanding these processes provides critical insights into plant stress tolerance and adaptive responses. This seminar will discuss emerging findings on ROS-driven modifications of chloroplast proteins and their implications for photoprotection, chloroplast proteostasis, and the coordination of cellular stress responses.