Reactive Oxygen Species and Plant Disease Resistance

Plants may successfully limit or even kill pathogens at least in part by eliciting spatial patterns of ROS production in different parts of invaded plant cells, e.g., the cell wall and plasma membrane. Recent research also suggests a significant contribution to plant disease resistance by ROS-mediated processes in the plant cuticle and intracellular organelles. The role of temporal patterns (i.e., proper timing) of ROS accumulation in eliciting an effective plant disease resistance is also discussed. Essentially, defense against pathogens could be very effective if it is a rapid, symptomless process, eliminating the pathogen in due time and not overusing resources of the plant, a process likely mediated by ROS. On the other hand, a delayed and failed attempt by the host to elicit resistance may result in massively stressed plant tissues and a partial or almost complete loss of control over pathogen invasion. Thus, it seems that when plants encounter pathogens they need to defend themselves simultaneously against biotic and abiotic stresses (i.e., pathogen accumulation and excessive cell/tissue death) by turning on two different types of—partially overlapping—signaling pathways that may function in parallel. Very recent interesting data suggest a pivotal role of autopropagating ROS waves in these signaling processes.