Abiotic Stress, Generation of Reactive Oxygen Species, and Their Consequences

Plants are exposed to a multitude of environmental stresses like drought, salinity, cold, heat, UV-B rays and heavy metal toxicity which severely impair plant development and reduce crop production. Reactive oxygen species (ROS) are produced in excess as by-products of physiological metabolism when the plant system is exposed to any kind of such stress. The enzymatic and ROS scavenging activity of SOD was discovered at least 45 years ago by J.M. McCord and I. Friovich in the year 1969. This discovery has ushered worldwide researches in the field of ROS biology. High accumulation of ROS in cells disrupts the overall homeostasis and triggers large scale oxidative damages resulting in widespread organelle damages and cell death. In course of the evolution, plants have developed multifarious complex signal transduction pathways which can combat the severe effects of abiotic stresses by maintaining ROS at a non-toxic level. Researchers have also identified crucial regulatory components which aid in manipulating the ROS levels to enhance stress tolerance in crops, which are socially and economically beneficial worldwide. In this book chapter, we have summarized the different players of ROS signaling and the various approaches adopted in plant oxidative stress biology to generate crops, sustainable even at sub-optimal conditions.