A chloroplast protein, PORC, undergoes heat-induced condensation and enhances thermotolerance in Arabidopsis

ABSTRACT: This project explores the role of chloroplast stress granules (cpSGs), specialized biomolecular condensates that form within chloroplasts under environmental stress, in enhancing plant resilience to heat. Focusing on the chlorophyll biosynthesis enzyme PROTOCHLOROPHYLLIDE OXIDOREDUCTASE C (PORC) in Arabidopsis thaliana, we demonstrate that PORC dynamically localizes to cpSGs in response to both acute (42°C) and prolonged (35°C) heat stress. Although PORC transcription remains heat-insensitive, its protein condenses into discrete puncta inside chloroplasts under elevated temperatures in a reversible and translation-dependent manner. Disruption of PORC function results in impaired thermotolerance, while overexpression enhances photosynthetic recovery, Photosystem II efficiency, and post-stress plant growth. Proteomic analyses of PORC-containing cpSGs reveal enrichment of photosynthetic proteins and stress-responsive factors, indicating that cpSGs function as protective hubs during heat stress. This study uncovers a novel mechanism of chloroplast stress adaptation and suggests that targeting cpSG dynamics and PORC activity could be a promising strategy for developing heat-resilient crops in the face of global climate challenges.

INSTRUMENT(S):

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

SUBMITTER: Peng Liu  

LAB HEAD: Monika Chodasiewicz

PROVIDER: PXD065110 | Pride | 2026-05-25

REPOSITORIES: Pride