Discovery of natural rosin-based preservative candidates to control Phytophthora capsici for postharvest disease management of solanaceae vegetables

Abstract

To mitigate the postharvest harm of pathogens on solanaceous vegetables, a series of natural rosin-1,2,4-triazole derivatives (totally 24) have been designed and developed. In vivo fungicidal activity evaluation showed that Co. 5 f could inhibit the growth of Phytophthora capsici (EC50 = 0.22 mg/L). In vivo activity suggested that Co. 5 f presented certain protective effect on bell pepper (64.93 % – 32.68 %) and tomato (91.93 % – 67.85 %) fruit. Additionally, Co. 5 f prevented declines in both weight and ascorbic acid levels and reduced the malondialdehyde content of bell peppers and tomato, suggesting its efficacy in vegetable preservation during storage. The physiological research revealed that Co. 5 f disrupted the mycelial cell membrane, accelerated the accumulation of reactive oxygen species, and decreased the enzyme activity of peroxidase (POD) and catalase (CAT) protein activities. Subsequently, quantum chemical calculations and molecular docking successfully predicted the active site of Co. 5 f. Metabolomics was then employed to elucidate the mechanism of physiological disorders, suggesting that differential metabolites were primarily enriched in the biosynthesis of amino acid and secondary metabolites. Transcriptomics was also utilized to further uncover the mechanism of mycelial metabolic disorders, revealing that differential genes were primarily enriched in the biosynthesis of secondary metabolites and amino acid. Additionally, the integration of physiology, metabolomics, transcriptomics, and computer-aided drug design unveiled the action mechanism of Co. 5 f against P. capsici, indicating that the regulation of POD and CAT biosynthesis involved six core genes, while the regulation of ARG, HIS, and TRP biosynthesis involved four core genes. Finally, the expression of these ten core genes was validated using quantitative real-time polymerase chain reaction (qRT-PCR). In summary, the above research integrated physiology, metabolomics, transcriptomics and computer-aided drug design to reveal the action mechanism of Co. 5 f, providing a certain theoretical support for the postharvest disease management of bell pepper and tomato fruit.