Untargeted Metabolomics of Brassica oleracea under Oleamide Supplementation: Resistance-Associated Changes

Oleamide, a fatty acid amide with potential bioactive properties against Xanthomonas campestris pv. campestris (Xcc), was evaluated for its impact on the metabolome of Brassica oleracea. Susceptible 'Early Big' plants at six weeks of age were pretreated with 60 µM oleamide. Twenty-four hours after treatment, plants were inoculated with Xcc race 1 either in the morning (AM) or evening (PM), and leaf tissue was collected 24 hours post-inoculation for untargeted metabolomic analysis. Oleamide supplementation induced substantial shifts in the metabolic profile compared to untreated plants, with pronounced effects in pathways associated with defense responses. Time-of-day-dependent variation in metabolite accumulation was also observed. These results indicate that oleamide modulates the metabolic landscape of B. oleracea, promoting early defense-related metabolic reprogramming during infection.