Genetic Analysis of Toxin Production by Fungi
Certain plant pathogenic fungi produce toxins, secondary metabolites that have adverse effects on plants. The roles of fungal toxins in pathogenesis have rarely been critically evaluated. However, at least 15 species of fungi produce special types of toxic molecules called host-specific toxins (Yoder, 1980). These metabolites are toxic to susceptible hosts of the fungus but not to resistant plants or nonhosts. Host-specificity suggests, but does not prove, that these toxins play significant roles in pathogenesis. To date, the most persuasive argument that can be made in support of pathological roles for these toxins is based on conventional genetic analyses. Toxin production, in three cases at least, is correlated genetically with fungal pathogenicity or virulence.
KeywordsToxin Production Cosmid Vector Unique mRNAs Cyclic Tetrapeptide Southern Corn Leaf Blight
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