Nematode-antagonistic trichothecenes from Fusarium equiseti.

A strain of the fungus Fusarium equiseti isolated from soybean cyst nematode secretes nematode-antagonistic compounds. Bioassay-guided fractionation of an extract of the culture broth was undertaken to identify the compounds. Fractions were assayed for activity against a root-knot nematode (Meloidogyne incognita), a plant pathogen that attacks the roots of numerous plant species. Two trichothecene compounds were isolated that inhibited egg hatch and immobilized second-stage juveniles of this nematode: 4,15-diacetoxy-12,13-epoxy-3,7-dihydroxytrichothec-9-en-8-one (4,15-diacetylnivalenol) and 4,15-diacetoxy-12,13-epoxy-trichothec-9-en-3-ol (diacetoxyscirpenol). This is the first published report of these compounds affecting plant-parasitic nematodes.