Abstract

Black spot disease causes significant yield and quality loss in Brassica vegetables. Therefore, developing effective management strategies is imperative to ensure both productivity and marketable quality in Chinese cabbage cultivation. We surveyed and isolated 396 Alternaria strains from infected Brassica vegetables, and confirmed that A. brassicae is the most pathogenic one. By screening and identifying the resistant and susceptible lines of Chinese cabbage, we performed a the widely targeted metabolomic analysis to explore the metabolic profiling of Chinese cabbage leaf samples in response to A. brassicae infection via a time course experiment. Coumarin-3-carboxylic acid and dicumarol were identified and functionally validated as effective antifungal compounds in vitro and in vivo assays, by activating the phenylpropanoid pathway. Furthermore, cinnamic acid of phenylpropanoid pathway was functionally validated to strongly inhibit the growth of the A. brassicae by in vitro assay. The extensive dataset of candidate metabolic compounds provided valuable insights for exploring A. brassicae - Brassica vegetables interactions, facilitating the for developing green pesticides and disease-resistant cultivars.