Chapter 9 - Oxidative Stress and Leaf Senescence: Important Insights

Abstract

Senescence is a plant developmental process that encompasses the synchronized degradation of macromolecules and the relocation of nutrients out of the tissue into the rest of the developing organs of the plant. It is a kind of programmed cell death phase that occurs as the last stage of leaf development. Leaf senescence is one of the prime yield-limiting traits in agronomic crops, which reduces the nutritional value of most of the crops. While the plants undergo different developmental phases, they also have to cope with wide-spectrum internal and external stresses; hence, the capability to acclimatize to the metabolic and environmental deviations is crucial for endurance. This process leads to the imbalanced equilibrium between oxidative and antioxidative capacities of the plant, which creates a characteristic oxidative environment resulting in the production of reactive oxygen species (ROS) and their more toxic derivatives, which damage vital cellular components. A range of developmental and environmental signals lead to leaf senescence, catalyzed by multiple, cross-linking pathways, many of which overlay with oxidative stress-response signals. The concurrent strategic studies of oxidative stress and leaf senescence have provided significant information that can be utilized for the improvement of both qualitative and quantitative crop yield. This perception has made it possible to design a path for the manipulation of leaf senescence for agricultural improvement via a number of strategies, such as manipulations of plant hormonal system, in-leaf senescence-specific transcription factors, and translation initiation factors. Hence, genetic-, proteomic-, or transcriptomic-level manipulation for attaining controlled leaf senescing and a less harmful oxidative environment is considered to be a precise operation for the betterment of plants (especially crops). This chapter summarizes the latest progress on the signaling role of ROS during the senescing phase and manipulative strategies to control the oxidative stress-senescence-induced damage in plants.