The Plant NADPH Oxidase RBOHD Mediates Rapid Systemic Signaling in Response to Diverse Stimuli

Reactive oxygen species produced by RBOHD mediate rapid, long-distance stress signals in plants. Sending Out an ROS Local stresses, such as the damage caused by an insect on one leaf, can produce signals that are transmitted systemically to distant parts of the plant that are not directly injured or stressed. These signals help the plant acclimate to environmental stress or defend against pathogens. Miller et al. show that the gene RbohD, which encodes a plant NADPH oxidase that generates reactive oxygen species, is critical for rapid systemic signaling in response to wounding, heat, cold, intense light, or increased salinity. Cell-to-cell communication and long-distance signaling play a key role in the response of plants to pests, mechanical wounding, and extreme environmental conditions. Here, we report on a rapid systemic signal in Arabidopsis thaliana that traveled at a rate of 8.4 centimeters per minute and was dependent on the respiratory burst oxidase homolog D (RbohD) gene. Signal propagation was accompanied by the accumulation of reactive oxygen species (ROS) in the extracellular spaces between cells and was inhibited by the suppression of ROS accumulation at locations distant from the initiation site. The rapid systemic signal was triggered by wounding, heat, cold, high-intensity light, and salinity stresses. Our results reveal the profound role that ROS play in mediating rapid, long-distance, cell-to-cell propagating signals in plants.