Role of Salicylic Acid in Enhancing Resistance and Metabolic Stability in Moth bean Against Cercospora Leaf Spot

Abstract

The present study investigates the role of salicylic acid (SA) in inducing systemic resistance and biochemical modulation in moth bean (Vigna aconitifolia) against Cercospora leaf spot disease caused by Cercospora canescens. In vitro assays confirmed a dose-dependent inhibition of C. canescens mycelial growth, with 200 μg mL-¹ SA achieving 95% inhibition. Moth bean seeds (var. RMO-2251) were treated with varying concentrations of SA (50, 100, 150, and 200 μg mL-1) through seed soaking and foliar application under pot conditions. The 200 μg mL-¹ concentration of SA was found most effective, recording the lowest disease intensity (17.55%) and highest disease control (63.02%). Biochemical analyses revealed significant enhancement in phenol and protein contents in SA-treated plants, particularly under disease stress, indicating an activated defense mechanism. Diseased tissues treated with 200 μg mL-¹ SA showed the highest phenol (6.11 mg g-¹) and protein content (20.53 mg g-¹). In contrast, infection led to a reduction in total sugars and malic acid; however, higher SA concentrations mitigated this decline, supporting improved metabolic stability. These results underscore the potential of salicylic acid, particularly at 200 μg mL-¹, as an effective chemical elicitor for enhancing disease resistance and physiological resilience in moth bean under biotic stress. The findings suggest that SA could be explored as a component of sustainable disease-management strategies for moth bean.