The Induction of Disease Resistance by Scopolamine and the Application of Extract Against Potato ( L.) Late Blight.

Late blight, caused by , is a devastating disease of potato. Our previous work illustrated that scopolamine, the main bioactive substance of extract, exerts direct inhibitory effects on , but it is unclear whether scopolamine and extract can boost resistance to late blight in potato. In this study, . is used to infect scopolamine-treated potato pieces and leaves, as well as whole potatoes. We found that scopolamine-treated potato is resistant to . both in vitro and in vivo. The treatment of 4.5 g/L scopolamine reduces the lesion size of whole potato to 54% compared with the control after 20 d of the infection of . The disease-resistant substance detection based on the kit method shows that scopolamine triggers the upregulation of polyphenoloxidase, peroxidase, superoxide dismutase activities, and HO contents in potato tubers, and the decline of phenylalanine ammonia lyase and catalase activity. A total of 1682 significantly differentially expressed genes were detected with or without scopolamine treatment through high-throughput transcriptome sequencing and the DESeq2 software (version 1.24.0), including 705 upregulated and 977 downregulated genes. Scopolamine may affect the genes functioning in the cell wall, membrane and the plant-pathogen interaction. The addition of extract could directly inhibit the mycelial growth of . on rye plate medium. In addition, . was found to be resistant to late blight in potato pieces treated with extract. extract can also be utilized in combination with the chemical fungicide Infinito in field experiments to lessen late blight symptoms and enhance potato yield. To our knowledge, this is the first study to detect the induction of disease resistance by scopolamine, and it also explores the feasibility of extract in potato disease resistance.