The ROS wave as a central catalyst of systemic acclimation and stress tolerance in plants.

Plants survive in environments where stress conditions fluctuate rapidly and unpredictably and their survival depends on their ability to transform local stress perception into coordinated whole-plant acclimation. Among the systemic signaling mechanisms studied to date, the 'reactive oxygen species (ROS) wave' has appeared as a fundamental process linking local stress perception to whole-plant acclimation. Initially defined as a self-propagating burst of ROS mediated by the plasma membrane enzyme RESPIRATORY BURST OXIDASE HOMOLOG D, the ROS wave is now recognized as one component of a highly integrated signaling network that dynamically interacts with calcium, electrical, hydraulic, redox, hormonal and other signaling molecules (i.e., gasotransmitters). Recent work has reshaped this view by revealing how different systemic signaling components interact with the ROS wave to mount stress-specific systemic responses and coordinate systemic acquired acclimation. Furthermore, ROS-dependent signals were found to propagate between neighboring plants, contributing to stress resilience at the community level. Here, we discuss recent advances that transformed our understanding of the ROS wave from an isolated signaling mechanism to a central regulator within an interconnected systemic signaling network.