Folic Acid: Boosting Stress Adaptation in Plants

Folic acid (FA), a member of the B-group vitamins, plays a critical role in plant development and environmental stress resilience. Under abiotic stresses—such as drought, salinity, heavy metals, and temperature extremes—and biotic challenges including pathogen infections and pest attacks, FA has emerged as a bioactive molecule regulating stress perception and defense activation. FA contributes to DNA synthesis and repair, redox regulation, amino acid metabolism, and methylation pathways. Recent findings highlight its role in enhancing antioxidant enzyme activities, modulating the expression of stress-related genes, stabilizing cellular structures, and supporting systemic resistance. Furthermore, FA appears to interact with phytohormonal signaling and nutrient transporters under stress. This chapter presents a comprehensive examination of FA’s molecular, physiological, and agronomic impacts under complex environmental conditions. It also explores the potential of exogenous FA applications as a low-cost, scalable solution to support crop productivity and sustainable agriculture.