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Poster

Session: Session 2 Presenting Authors at Posters (Evens)

P-402 - Cold primes plant immunity via plastid ascorbate peroxidases

Thursday, July 17, 2025
13:30 - 15:15  
Location: Confex Hall 3
Plant Regulation of biotic and abiotic stress – trade-offs
Environmental conditions shape a plant’s capabilities during interactions with microbes. We investigated whether and how plants benefit from a single 24-hour cold exposure (4°C) during subsequent infections with biotrophic or necrotrophic pathogens. This cold pretreatment effectively primed Arabidopsis thaliana Col-0 for enhanced resistance against the virulent pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) for several days. Cold exposure also enhanced resistance to the necrotrophic fungus Botrytis cinerea when infection occurred immediately after treatment. Although not shared by all Arabidopsis accessions, this phenomenon was also observed in Valerianella locusta. To clarify molecular components of cold-enhanced pathogen resistance, we investigated the role of chloroplast-associated ascorbate peroxidases (APX). Knockout mutants lacking stromal APX (sAPX) or thylakoid-bound APX (tAPX) failed to exhibit pronounced cold-induced resistance. Interestingly, sAPX and tAPX play distinct roles in cold priming for pathogen defence. For instance, cold-pretreated Col-0 and tapx lines exhibited enhanced reactive oxygen species (ROS) production in response to B. cinerea, whereas sapx plants showed increased B. cinerea-triggered ROS even without prior cold exposure. Our findings highlight the role of plastid peroxidases in cold-induced immune memory against bacterial and fungal pathogens and deepen our understanding of how abiotic changes, such as cold, influence plant immunity.