Frontiers in Plant-Soil Interaction | 2021
Biotic stresses on plants: reactive oxygen species generation and antioxidant mechanism
Abstract
Abstract During the course of growth and development, plants encounter many biotic stressors (pathogens and herbivores), which affect crop productivity to a larger extent. Biotic stresses lead to various physiological, biochemical, molecular, and metabolic alterations in plants. One of the crucial changes, that is observed in response to pest and pathogen attack, is the generation of reactive oxygen species (ROS). The primary sites of ROS generation are chloroplast, mitochondria, and peroxisomes, but during stress, ROS are also generated at secondary sites, which include endoplasmic reticulum, cell wall, cell membrane, and apoplast. ROS includes free radicals (O2•−, OH•) as well as nonradicals (H2O2, 1O2). A high concentration of ROS leads to oxidative stress and causes lipid peroxidation, chlorophyll damage, redox imbalance, and nucleic acid and protein degradation. Therefore in order to reduce the deleterious effects of ROS, plants have developed antioxidant mechanisms. However, a low/moderate level of ROS also act as a signaling molecule and interact with other signaling compounds and activate plant defense/tolerance mechanisms.