Reactive Oxygen Species Generation, Antioxidants and Regulating Genes in Crops under Abiotic Stress Conditions

Abstract

Among the abiotic stresses such as drought, cold, salt and heat causes reduce the plant growth and crop yield worldwide. Reactive oxygen species (ROS) i.e. hydrogen peroxide (H2O2), superoxide (O2 • –), hydroxyl radical (OH• – and singlet oxygen (1O2) are by products of metabolisms, and are specifically controlled by enzymatic and non-enzymatic antioxidant defense mechanisms. Under abiotic stress conditions, ROS are significantly accumulated, which reason oxidative damage and ultimately resulting in cell death. Recently, reported that, ROS have been also recognized as key players in the complex signaling network of plants stress responses. The involvement of reactive oxygen species (ROS) in signal transduction indicates that there must be synchronized function of network regulations to maintain the ROS at non-toxic levels, among ROS generation and ROS-scavenging pathways. Research evidence showed that ROS play vital roles in abiotic stress responses of crop plants for the activation of stress-response and defense pathways. More decisively, manipulating ROS levels offers an opportunity to improve plantstress tolerance towards abiotic stress conditions. This chapter presents an understanding to knowledge about homeostasis regulation of ROS in crop plants. In this chapter, we are summarizing the 144defense machinery i.e. enzymatic and non-enzymatic antioxidants, genes involved in abiotic stress tolerance of plants through ROS regulation. Comprehensive knowledge of ROS action and their regulation will enable to develop strategies to development of abiotic stress tolerance crop plants.