ROS modulation in crop plants under drought stress

Plants being sessile organism have evolved mechanisms that help them survive, adapt, or tolerate drought stress. During drought stress enhanced reactive oxygen species (ROS) production is inevitable; the phytotoxic levels of ROS are detrimental leading to cellular damage and death. However, at low concentration, they act as key signaling molecule by triggering various stress-responsive pathways and initiating cross-talk among these pathways. These are fine-tuned by the ROS producing enzymes and the ROS scavenging enzymes and antioxidant system for their removal, thus modulating intracellular ROS concentration and maintaining the redox status of the cell. ROS are linked to sensing and activation of ABA, other hormones, respiratory burst oxidase homologs (RBOH) and Ca2+ fluxes and is likely to be involved both upstream and downstream of the ABA-dependent/independent signaling pathways under drought stress. Thus, modulating ROS levels provides an opportunity to enhance tolerances of crop plants under drought and various other abiotic stress conditions.