Reactive oxygen species function as signaling molecules in controlling plant development and hormonal responses.

Reactive oxygen species (ROS) serve as second messengers in plant signaling pathways to remodel plant growth and development. New insights into how enzymatic ROS-producing machinery is regulated by hormones or localized during development have provided a framework for understanding the mechanisms that control ROS accumulation patterns. Signaling-mediated increases in ROS can then modulate the activity of proteins through reversible oxidative modification of specific cysteine residues. Plants also control the synthesis of antioxidants, including plant-specialized metabolites, to further define when, where, and how much ROS accumulate. The availability of sophisticated imaging capabilities, combined with a growing tool kit of ROS detection technologies, particularly genetically encoded biosensors, sets the stage for improved understanding of ROS as signaling molecules.