P-423 - The interaction between photorespiration and plant immunity

Plants are constantly exposed to a variety of pathogens and insect pests, and have evolved sophisticated immune systems to detect and defend against these threats. This defense mechanism involves numerous biological and metabolic pathways. While primary metabolic processes like photosynthesis have been shown to be downregulated during defense responses, the regulation of photorespiration remains largely unexplored. In this study, we subjected wild-type Arabidopsis Col-0 plants to low CO₂ conditions, which promote photorespiration flux. We collected samples at 1 hour and 8 hours post CO₂ shift and analyzed their transcriptomic data. By comparing these samples with those maintained under ambient CO₂ conditions, we observed that the 1-hour samples exhibited a greater number of differentially expressed genes (DEGs) compared to the 8-hour samples. This suggests that the low CO₂ shift induces an initial stress response at 1 hour, followed by acclimation at 8 hours post-shift. Notably, the DEGs in the 1-hour samples were enriched in several defense-related Gene Ontology (GO) terms. Additionally, KEGG pathway enrichment analysis revealed the involvement of key defense pathways, including plant-pathogen interactions and the MAPK signaling pathway. Further transcriptomic analyses are underway to deepen our understanding of the role of photorespiration in plant immunity. Overall, our findings highlight a close and robust interaction between photorespiration and plant immune responses.