Insights into Biotic Stress Management by Plants Using Phenolic Compounds

Plants are sessile in nature and are not able to escape from various pathogens including bacteria, fungi, viruses, nematodes, insects, weeds, and herbivores which cause biotic stress. These agents can right away deprive host by absorbing their nutrients and lead to plants’ death. In this way, it could be the major reason of pre/postharvest crop loss. Plants counter biotic stress through different strategies or defense mechanisms including resistant genes and antioxidant defense system. Plants sense external stimuli by sensors present on cell membrane or cytoplasm, and it transfers to nucleus and ultimately activates signal transduction machinery. When the plant is under any kind of stress, there is the excessive reactive oxygen species (ROS) or reactive nitrogen species (RNS) production, and their homeostasis is very necessary to prevent from oxidative damage. Phenolics are a group of plant secondary metabolites that contain one or more hydroxy derivatives of benzene rings and have an ideal structure to scavenge ROS. Phenolics protect the plant by binding to the cell wall, deposition of lignin to interrupt the entry of pathogens, and conversion of simplex phenolics to complex under stress. This chapter will highlight the role, functions, targets, and mode of action of various phenolics in amelioration of biotic stress.