Plant NADPH Oxidases

Reactive oxygen species (ROS) are signaling molecules that play important roles in many processes in plants, including development, immunity, and acclimation to different environmental stimuli. The intensity, duration and localization of ROS signals are determined by a delicate equilibrium between ROS production, scavenging, and transport mechanism within the ROS network. Within this network of genes, plant NADPH oxidases (NOXs), or respiratory burst oxidase homologues (RBOHs), comprise a small, but highly important, conserved gene family that generates ROS. RBOH-generated ROS drive signaling cascades regulating key cellular processes, tissue specific programs, and systemic responses via cell-to-cell communication. In addition, RBOH proteins serve as regulatory hubs for calcium signaling and other secondary messengers, such as NO. In this chapter we summarize the current understanding of the activity, regulation and different roles of RBOH proteins in plants.