Signaling Pathway of Reactive Oxygen Species in Crop Plants Under Abiotic Stress

Global climate change is linked with various abiotic stresses like drought, salt, temperature, and heavy metals, which can rigorously affect growth, development, and physiological functioning and ultimately cause yield reduction of crops. Environmental stresses pose oxidative damage in plants due to the denaturation of structural and functional proteins. Oxidative damage is usually triggered by reactive oxygen species (ROS), for example, singlet oxygen, hydrogen peroxide, superoxide ions, and hydroxyl radical. As a defense mechanism, parallel cellular responses and cell signaling pathways are activated in plants for controlling the level of these reactive oxygen species. This cellular signaling induces the development of new metabolic pathways by synthesizing low-weight metabolites and by modifications in phytohormonal levels. It is well established by now that the role of ROS under abiotic stresses is very significant for crop plants. More importantly, there is a potential of increasing stress tolerance of crop plants by manipulation of ROS. However, their responses can vary according to stress conditions and crop species. The current chapter enlightens the roles of ROS under abiotic stresses and their significance as major signals for maintaining cellular homeostasis and improving plant survival under harsh environmental conditions.