Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 6, 2000
Publication Date: N/A
Technical Abstract: New methods to control plant-parasitic nematodes are being sought to replace methyl bromide, which under international agreement is being phased out for agricultural use. We are isolating nematicidal compounds produced by fungus strains associated with root-dwelling nematodes. Bioassay-directed fractionation of an extract of Fusarium equiseti culture broth yielded the compounds 4,15-diacetylnivalenol and diacetoxyscirpenol, both trichothecenes. These compounds strongly inhibited in-vitro egg hatch and juvenile mobility of the root-knot nematode, Meloidogyne incognita. However, trichothecenes are toxic to a broad spectrum of organisms, including humans, limiting their potential usefulness as control agents for plant-parasitic nematodes. In addition to the Fusarium compounds, nematode-antagonistic compounds produced in the culture broth of a second fungus species are currently being purified. An Amberlite XAD-16 extract of the culture broth was fractionated using medium-pressure liquid chromatography with Toyopearl HW40 resin and silica gel, and the major components of the most biologically active fraction are being purified using reversed-phase HPLC. The identities of the nematode-antagonistic compounds from the second fungus species are yet to be determined. Identification of natural products from fungi associated with plant-parasitic nematodes can provide lead compounds for novel nematicides as well as increase our understanding of how nematode-antagonistic fungi affect their nematode associates.