Temporal Metabolomic Dynamics of Methyl Jasmonate-Induced Reprogramming in Vitis vinifera L. cv. Tempranillo Leaves

Methyl jasmonate (MeJA) is a defence-related phytohormone that triggers metabolic reprogramming in grapevines and modulates pathways associated with stress responses and secondary metabolism. However, the temporal organisation of leaf metabolic responses following MeJA elicitation remains insufficiently characterised. In this study, an untargeted metabolomic approach based on UPLC-QTOF-MS was applied to investigate the time-resolved metabolic response of Vitis vinifera L. cv. Tempranillo leaves following foliar application of 10 mM MeJA under controlled greenhouse conditions. Leaf samples were collected at 0, 3, 6, 18, 24, and 48 h post-treatment. After quality filtering, 2552 metabolite features were detected, of which 40 discriminant features met stringent statistical criteria (maximum fold change ≥ 2 and p ≤ 0.05). Putative annotation according to Metabolomics Standards Initiative guidelines (MSI levels 2–3) revealed modulation of several metabolite classes, including carbohydrate-derived conjugates, terpenoid-related metabolites, hydroxycinnamic acid derivatives, and flavonoid-associated compounds. Temporal profiling revealed structured and non-monotonic metabolic responses characterised by rapid early changes between 3 and 6 h, followed by delayed accumulation patterns peaking around 24 h. Early phases were mainly associated with carbohydrate-related metabolites, suggesting rapid redistribution of carbon resources after elicitor perception. These results indicate that MeJA-induced metabolic adjustment in Tempranillo leaves occurs through temporally differentiated response phases rather than a uniform metabolic shift, providing a time-resolved metabolomic framework for interpreting elicitor-driven defence responses in grapevine.