CYCLOSPORINE-C IS THE MAIN ANTIFUNGAL COMPOUND PRODUCED BY ACREMONIUM-LUZULAE

A strain of Acremonium luzulae (Fuckel) W. Gams was selected in screen ing new microorganisms for biological control of fruit postharvest dis eases, especially gray and blue mold diseases on apples and strawberri es, This strain manifests a very strong activity against a large numbe r of phytopathogenic fungi, In this work, the product responsible for this antifungal activity was isolated from modified Sabouraud dextrose broth cultures of A. luzulae. It was purified to homogeneity by rever se-phase column chromatography. On the basis of UV, infrared, and H-1 and C-13 nuclear magnetic resonance spectra, mass spectral analysis, a nd the amino acid composition of the acid hydrolysates, the antibiotic was determined to be cyclosporin C. Cyclosporin C showed a broad-spec trum activity against filamentous phytopathogenic fungi but no activit y against bacteria or yeasts, Its antifungal activity is only fungista tic. In contrast to Tolypocladium inflatum, another cyclosporin-produc ing strain, A, luzulae, did not produce additional cyclosporins, This was confirmed by in vivo-directed biosynthesis.