THE ANTIFUNGAL PROPERTIES OF MINIMEDUSA-POLYSPORA

Colonies of Fusarium oxysporum f. sp. narcissi in dual culture with Mi nimedusa polyspora were overgrown, with the contents of the hyphae sho wing coagulation and vacuolation followed by cell death. Lysis ensued after development of numerous small holes in the hyphae followed by ra pid disintegration of the walls. Minimedusa also directly entwined hyp hae of F. oxysporum by means of short side branches which developed ap pressorium-like attachment structures and wall penetration pegs. Whils t hyphae of Minimedusa were not seen to grow intracellularly they were observed within the remains of dead hyphae of Fusarium. Neutral red s taining indicated that Fusarium hyphae were apparently killed prior to contact between the two fungi. Bioautography and NMR studies on cultu re filtrates of Minimedusa revealed five antifungal triene compounds, of which one was a polyacetylene component, thereby providing further evidence for antibiosis as the primary mechanism of antagonism.