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

Aims: The 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 results: A 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.

Conclusions: Antifungal 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 study: Rimocidin 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.

Colletotrichum coccodes; anthracnose; antifungal agent; microbial metabolites; plant disease control; rimocidin.