Secondary metabolites of Fusarium venenatum strains with deletions in the Tri5 gene encoding trichodiene synthetase

Abstract

We studied the secondary metabolites of a number of strains of F. venenatum, some of which had the gene for trichodiene synthetase deleted. Under optimum fermentation conditions, wild type isolates produced the trichothecenes diacetoxyscirpenol and related metabolites, isotrichodermin and isotricodermol, the modified trichothecenes sambucinol and apotrichothecene, the sesquiterpenes culmorin and culmorone and derivatives and trace amounts of the cyclic peptide enniatin B. These results are compared to metabolite production by other members of the section Discolor. Strains without trichodiene synthetase produced no trichothecenes or modified trichothecenes. In these strains, production of culmorin family compounds was greatly attenuated despite the elimination of an acetate-derived biosynthetic pathway. This was contrary to expectations. No other metabolites were produced by these strains evidenced by chemical or cytotoxicity analyses of fractionated extracts.

Key Words:

• chemotaxonomy
• trichothecenes