ROS Homeostasis in Abiotic Stress Tolerance in Plants

Abstract

Climate change-induced abiotic stress results in crop yield and production losses. These stresses result in changes at the physiological and molecular level that affect the development and growth of the plant. Reactive oxygen species (ROS) is formed at high levels due to abiotic stress within different organelles, leading to cellular damage. Plants have evolved mechanisms to control the production and scavenging of ROS through enzymatic and non-enzymatic antioxidative processes. However, ROS has a dual function in abiotic stresses where, at high levels, they are toxic to cells while the same molecule can function as a signal transducer that activates a local and systemic plant defense response against stress. The effects, perception, signaling, and activation of ROS and their antioxidative responses are elaborated in this review. This review aims to provide a purview of processes involved in ROS homeostasis in plants and to identify genes that are triggered in response to abiotic-induced oxidative stress. This review articulates the importance of these genes and pathways in understanding the mechanism of resistance in plants and the importance of this information in breeding and genetically developing crops for resistance against abiotic stress in plants.

Keywords: ROS reactive genes; antioxidative; environmental stresses; enzymatic and non-enzymatic enzymes; hormones; signaling.

Figure 1

A diagrammatic representation of the processes in the chloroplast during stress where reactive oxygen species (ROS) is produced through inhibition of CO₂, and low water levels are due to stress. The electron transport chain (ETC) in the photosystem (PS) is the main source of ROS in chloroplast.

Figure 2

The process of redox in the mitochondria. Any form of stress causes alleviation in ROS due to ATP synthesis, leading to a reduction in the ubiquinone pool (UQ) pool. Several enzymes work together to manage ROS levels in mitochondria.

Figure 3

The process of redox in peroxisome during stress. Xanthine oxidases convert xanthine and hypoxanthine to uric acid and O₂⁻, while the proximal membrane produces O₂⁻ via NADH and Cytb.

Figure 4

The processes involved in the production and control of ROS in different organelles within a plant system. The above is observed during stress response in plants. All these organelles are collectively responsible at maintaining ROS homeostasis in the cell.

Figure 5

The pathway taken from the time of stimulus to the activation of genes downstream and the genes involved in the regulation of this pathway.