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United States Department of Agriculture

Agricultural Research Service

Title: Fungal Natural Products Toxic to the Root-Knot Nematode

Authors
item Nitao, James
item Meyer, Susan
item Chitwood, David

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 1999
Publication Date: N/A

Technical Abstract: The root-knot nematode Meloidogyne incognita is a major pest throughout the world, attacking over 700 species of crops, grasses, pasture plants, shrubs, and trees. The imminent ban of the widely used nematicide methyl bromide in the U.S. will severely restrict control options for this destructive plant parasite in agricultural systems. As part of our search for biorational alternatives, we are isolating fungal natural products that reduce root-knot nematode egg hatch and larval mobility in vitro. Amberlite XAD gel was used to extract culture broths of Fusarium equiseti and a second fungal species. Nematode-antagonistic compounds in the Fusarium extract were separated from polar constituents by partitioning between water-methanol and ethyl acetate. Fractionation of the ethyl acetate extract on a series of silica gel chromatography columns produced fractions that reduced egg hatch by 66% when tested at 50 micro g/ml. Components of the active Fusarium fractions are being purified with reversed-phase HPLC. The XAD extract of the second fungal species yielded a methanol-soluble fraction that reduced egg hatch by 40% when tested at 250 micro g/ml. Further bioassay-directed separation of the methanol-soluble fraction with reversed-phase column chromatography is expected to yield a more potent fraction.

Last Modified: 12/20/2014
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