Antifungal activity of rimocidin and a new rimocidin derivative BU16 produced by Streptomyces mauvecolor BU16 and their effects on pepper anthracnose

AimsThe objective of this study was to explore antifungal metabolites targeting fungal cell envelope and to evaluate the control efficacy against anthracnose development in pepper plants. Methods and ResultsA natural product library comprising 3000 microbial culture extracts was screened via an adenylate kinase (AK)-based cell lysis assay to detect antifungal metabolites targeting the cell envelope of plant-pathogenic fungi. The culture extract of Streptomyces mauvecolor strain BU16 displayed potent AK-releasing activity. Rimocidin and a new rimocidin derivative, BU16, were identified from the extract as active constituents. BU16 is a tetraene macrolide containing a six-membered hemiketal ring with an ethyl group side chain instead of the propyl group in rimocidin. Rimocidin and BU16 showed broad-spectrum antifungal activity against various plant-pathogenic fungi and demonstrated potent control efficacy against anthracnose development in pepper plants. ConclusionsAntifungal metabolites produced by S.mauvecolor strain BU16 were identified to be rimocidin and BU16. The compounds displayed potent control efficacy against pepper anthracnose. Significance and Impact of the StudyRimocidin and BU16 would be active ingredients of disease control agents disrupting cell envelope of plant-pathogenic fungi. The structure and antifungal activity of rimocidin derivative BU16 is first described in this study.