Relevance of the antioxidative mechanism during plant-microbe interaction

Abstract

Various cellular oxidation processes occur in the plant cell for its growth, development, and adaptation to stress. These oxidation reactions produce reactive oxygen species (ROS) as their normal by-products. Normal functioning of the plant cell is defined by its ability in sustaining the subtle balance between ROS generation and scavenging. The interaction between plants and microbes induces oxidative stress by the overproduction of ROS due to breaching this delicate balance. This oxidative stress leads to substantial cellular damage due to protein degradation, lipid peroxidation, nucleic acid oxidation as well as programmed cell death, facilitating the pathogen to optimize its tissue colonization and nutrient uptake. In response, the plant cells protect themselves by counteracting against these toxic oxygen intermediates by deploying both nonenzymatic as well as enzymatic components of antioxidants. Hence, eventually, an increment in antioxidant activity can be anticipated as a notable indicator for stress management in plant microbe interaction, for example, H2O2 elimination by catalase, superoxide ion reduction by SOD, lignification, suberification, and polymerization of hydroxy-proline-rich glycoproteins, regulation of cell wall elongation by POXs and PAL being the primary enzymes of the phenylpropanoid pathway, antioxidants are involved in healing of wound in addition to resistance reaction against pathogens in plant microbe interaction, to name a few. In this milieu, this chapter presents a brief introduction to antioxidants, the mechanism of operation in plants, its dynamics under abiotic and biotic stress in general and microbial interaction, in particular, along with its role in protecting plants against phytopathogens. © 2023 Elsevier Inc. All rights reserved.