Gallic Acid: Role in Plant Defense Mechanisms Against Stress

Gallic acid, a naturally occurring phenolic compound, plays a pivotal role in enhancing plant defense mechanisms against abiotic and biotic stresses. This chapter explores the benefits of exogenous application of gallic acid to improve plant resilience, growth, and productivity under stressful conditions. Under abiotic stresses such as drought, salinity, extreme temperatures, and heavy metal toxicity, gallic acid mitigates oxidative damage, stabilizes cellular membranes, and modulates ion homeostasis. In biotic stress contexts, it exhibits antimicrobial activity, triggers induced systemic resistance (ISR), and alters secondary metabolite production to strengthen plant immunity. Mechanistic insights reveal gallic acid’s influence on gene expression, hormonal signaling, and possibly epigenetic regulation. Its application in biostimulants, nanotechnology-enabled delivery, and seed priming shows promise in sustainable agriculture. Future research should optimize its practical use and explore synergistic effects with other bioactives.