| Abstract |
: |
Colonies of Fusarium oxysporum f. sp. narcissi in dual culture with Minimedusa polyspora were overgrown, with the contents of the hyphae showing coagulation and vacuolation followed by cell death. Lysis ensued after development of numerous small holes in the hyphae followed by rapid disintegration of the walls. Minimedusa also directly entwined hyphae of F. oxysporum by means of short side branches which developed appressorium-like attachment structures and wall penetration pegs. Whilst hyphae of Minimedusa were not seen to grow intracellularly they were observed within the remains of dead hyphae of Fusarium. Neutral red staining indicated that Fusarium hyphae were apparently killed prior to contact between the two fungi. Bioautography and NMR studies on culture 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. |
