ARS | Publication request: TRICHOTHECENE MYCOTOXINS PLAY A ROLE IN VIRULENCE OF GIBBERELLA EAR ROT OF CORN

Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 24, 1998
Publication Date: N/A

Technical Abstract: Trichothecene-producing and -nonproducing Fusarium graminearum strains were tested for their ability to cause Gibberella ear rot in replicate field trials at two locations in 1996. This was accomplished by inoculating Zea mays ears with transgenic F. graminearum strains in which the trichothecene biosynthetic pathway had been knocked out via the specific disruption of the trichodiene synthase gene. A derivative revertant strain in which trichothecene production had been restored through recombination was also used. A silk channel inoculation method was employed at both the Ontario and Illinois test sites. In addition, a kernel puncture method was used at the Ontario location. Harvested corn was analyzed for visual disease severity, yield, deoxynivalenol (DON) concentration, and fungal biomass either by ergosterol quantitation and/or fungal DNA quantitation by means of PCR. The trichothecene-nonproducing strains were still pathogenic but less virulent on corn than the trichothecene-producing progenitor and revertant strains, as assayed by most parameters. This suggests that the trichothecenes act as virulence factors to enhance the aggressiveness of F. graminearum on corn.