Reactive Oxygen Signaling in Plants

Reactive oxygen species (ROS) control many different processes in plants, including growth, development, and response to biotic and abiotic stimuli. However, as toxic molecules ROS are also capable of causing cell injury or death. How this conflict is resolved in cells is largely unknown. Nonetheless, it is clear that the steady-state level of ROS in cells needs to be tightly regulated. In the flowering plant Arabidopsis thaliana, a network of more than 150 genes is involved in managing the level of ROS in cells. This network is highly dynamic and redundant, and encodes for ROS sensing, scavenging, and producing proteins. Although recent studies unraveled some of the key players of the ROS network, many questions related to its mode of regulation, its protective roles, and its modulation of signaling networks that control growth, development, and stress responses remain unanswered. This chapter gives an overview of the ROS network in plants and discusses its complexity and the challenges it poses for researchers attempting to study basic processes in plant biology.