Fungichromin: a substance from Streptomyces padanus with inhibitory effects on Rhizoctonia solani.

Streptomyces padanus strain PMS-702 is an antagonist of Rhizoctonia solani AG-4, the causal agent of damping-off of cabbage. Treatment of cabbage seeds with the culture filtrate of S. padanus strain PMS-702 was effective in reducing the incidence of damping-off of cabbage. The major active ingredient from the culture filtrate of S. padanus strain PMS-702 was purified by silica gel column chromatography and identified as the polyene macrolide, fungichromin, by NMR and mass spectral data. Bioassay studies showed that fungichromin had a strong antifungal activity against R. solani AG-4, and its minimum inhibitory concentration (over 90% inhibition) was found to be 72 microg/mL. This is the first report of fungichromin from S. padanus as an active ingredient for the control of Rhizoctonia damping-off of cabbage.