Dynamics of plant immune MAPK activity and ROS signaling in response to invaders

Plants show sequential immune responses, pattern-triggered immunity (PTI), followed by effector-triggered immunity (ETI). The long-lasting MAPK activity during ETI triggers activation of robust ROS burst mediated by an NADPH oxidase in plasma membrane, also in chloroplasts. Mining of hydrogen peroxide receptors, ROS sensor proteins seems important to elucidate the ROS-dependent cellular events. We also introduce live-imaging system of MAPK activity by producing FRET-based biosensor at the single cell and organelle levels. The observation of spatiotemporal MAPK activities in response to pathogen and herbivore attacks will provide new insights into the positioning of MAPK and ROS in the plant immunity. •MAPKs activate ROS bursts by NADPH oxidases during ETI.•MAPKs induce chloroplastic ROS burst during ETI.•Role of ROS sensor proteins on ROS signaling pathways during immune responses.•Live-imaging system of MAPK activity by FRET-based biosensor.