ROS-dependent signaling and redox subcellular changes triggered by flg22 in Arabidopsis

CISLAGHI AP, ; ALVAREZ ME

Congreso; RAFV Conference XXXIII Argentinian meeting of Plant Physiology; 2021

In plants, perception of pathogen-associated molecular patterns (PAMPs) by surface-localized pattern recognition receptors (PRRs) activates the NADPH oxidase RBOHD that functions as an essential regulator of reactive oxygen species (ROS) levels. This biotic stress increases the generation of ROS that need to be detoxified to avoid deleterious effects. However, at the same time ROS are exploited for redox signaling to induce defences. In recent years it has become (increasingly) clear that oxidative and reductive modifications are confined in a spatio-temporal manner. However, our understanding of how compartment-specific redox dynamics might operate in retrograde signaling and stress defense responses remains limited. Here we used the genetically encoded biosensors Grx1-roGFP2 to record dynamic changes in glutathione redox potential (EGSH) in cytosol and chloroplasts of Arabidopsis leaf discs treated with flg22. ROS production was monitored using a luminol-based assay. The oxidation of both intracellular probes gradually increased over time after flg22 treatment, succeeding apoplastic ROS accumulation. In contrast to the transient apoplastic ROS burst, we detected a prolonged oxidation in both cytosol and chloroplasts upon flg22 perception which may be affected by NADPH oxidase. Our results provide new insights on the interplay between apoplastic and intracellular ROS dynamics and highlight the importance of redox balance within organelles during plant immune response.