Metabolic Response Induced by Methyl Jasmonate and Benzothiadiazole in Vitis vinifera cv. Monastrell Seedlings

This study evaluates the effects of the elicitors methyl jasmonate (MeJ) and benzothiadiazole (BTH) on the synthesis of phenolic compounds in Vitis vinifera cv. Monastrell seedlings over 72 h. Results show that both elicitors induce the accumulation of stilbenes and phenolic acids, essential compounds in plant defence against pathogens. Specifically, MeJ significantly increased the levels of astringin, T-resveratrol, and miyabenol C, known for their antifungal properties, indicating a rapid and effective activation of plant defences. Discriminant analysis revealed that MeJ and BTH markedly altered the phenolic profile, highlighting their role in modulating defence responses. However, their combined application exhibited antagonistic effects on some compounds, suggesting an adaptive metabolic response. The defence response was transient, with peak concentrations observed within the first 24 h, followed by down-regulation, optimising the plant’s energy resources. These findings suggest that MeJ and BTH can enhance the resistance of the Monastrell variety, potentially reducing pesticide use in sustainable viticulture. Further studies are needed to assess their long-term effects under field conditions, considering environmental variables and optimal application rates.