Jasmonic Acid-Mediated Defense in Vicia faba: Alleviating Fungicide-Induced Oxidative Stress

Abstract

Plants are constantly subjected to various environmental stressors that significantly impede their growth and limit agricultural productivity. These stressors are classified as abiotic (such as extreme temperatures, drought, salinity, radiation, and heavy metals) and biotic (including fungi, bacteria, viruses, nematodes, and herbivores). To counter these challenges, plants have developed sophisticated defense mechanisms that involve sensing stress signals, activating signaling cascades, and initiating cellular responses. In agricultural settings, plants frequently face combined stress conditions, intensifying damage and reducing yields. Among the most damaging biotic agents are fungi and oomycetes, which are responsible for substantial global crop losses. The faba bean (Vicia faba L.), a widely cultivated legume, is highly susceptible to various fungal diseases such as rust, chocolate spot, ascochyta blight, leaf spots, and root rot complexes, often resulting in severe defoliation and yield decline. Disease management traditionally involves resistant crop varieties, improved cultural practices, and the extensive use of fungicides like mancozeb. While fungicides such as mancozeb effectively suppress pathogens, their overuse leads to oxidative stress due to the accumulation of reactive oxygen species (ROS), which disrupt cellular homeostasis. Plants mitigate oxidative damage through robust antioxidant systems comprising enzymatic (SOD, CAT, POD) and non-enzymatic (ascorbate, glutathione, carotenoids) components. Plant growth regulators (PGRs), particularly jasmonic acid (JA), have emerged as critical tools in enhancing plant resilience by strengthening antioxidant defenses and regulating stress responses. JA modulates stress adaptation by interacting with other phytohormones and regulating key physiological processes, thereby offering a promising, eco-friendly strategy to reduce the adverse impacts of both environmental stress and chemical treatments.