Journal of Plant Pathology (2003) 85, p. 278 (Covarelli et al.)

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L. Covarelli, A.S. Turner and P. Nicholson (2003)
Effect of fungicides on deoxynivalenol biosynthesis in vitro and expression of tri genes in the head blight pathogen Fusarium culmorum
Journal of Plant Pathology 85 (4), 278-278
X Meeting, Italian Society for Plant Pathology (oral presentation)
Abstract: Liquid media containing different nitrogen sources (1.65 gl-1 ammonium sulphate, 0.75 gl-1 urea, 2.125 gl-1 sodium nitrate), 10 gl-1 of glucose and nitrogen free Vogel's medium, were assayed in order to identify a defined medium for optimal production of the trichothecene mycotoxin deoxynivalenol (DON) in vitro by F. culmorum and to investigate, in such a medium, the effect of some fungicides on DON production and on the regulation of the trichothecene biosynthesis pathway by studying Tri5 and Tri6 gene expression. The effect of sub-lethal concentrations of the fungicides azoxystrobin, trifloxystrobin, kresoxim-methyl (strobilurines) and tebuconazole (a triazole), on biosynthesis (DON) by Fusarium culmorum was studied. Trifloxystrobin and azoxystrobin significantly reduced the accumulation of DON in the culture medium. Kresoxim-methyl and tebuconazole did not significantly reduce the accumulation of DON although levels were lower than those in non-amended cultures. Post-inoculation addition of trifloxystrobin significantly reduced the accumulation of DON when added to cultures prior to the onset of trichothecene biosynthesis. The expression of Tri6 and Tri5 genes, assayed by RT-PCR, showed that trifloxystrobin was acting through inhibiting the initiation of trichothecene biosynthesis. This study provides new information on the regulation of DON biosynthesis and the effect of selected fungicides on mycotoxin production in F. culmorum. However, care must be taken in extrapolating the information from such in vitro studies to field situations.
Database assignments for author(s): Paul Nicholson, Lorenzo Covarelli

Research topic(s) for pests/diseases/weeds:
control - general
molecular biology - genes

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Fusarium culmorum