Submitted to: American Society for Microbiology Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 12, 1996
Publication Date: N/A
Technical Abstract: The production of trichothecene toxins by Fusarium species represents a serious problem for U.S. agriculture. Our efforts to control trichothecene production on cereal crops have focused on understanding both the biosynthesis of trichothecenes and their role in plant diseases. We have shown that the trichothecene pathway genes are clustered. At least nine trichothecene pathway genes have been identified within a 23 Kb region of DNA, including genes encoding pathway enzymes, a transcription factor, and a possible transporter. To genetically isolate trichothecene production as a factor in wheat head scab (WHS) caused by F. graminearum we have used gene disruption to construct Tri5- mutants that are unable to produce trichothecenes. In extensive growth chamber and field trials using both spring and winter wheat varieties these Tri5- mutants caused less severe WHS than both Tri5+ revertant and wild-type trichothecene-producing strains of F. graminearum. The results strongly support a role for trichothecenes in Fusarium WHS. The identification of trichothecenes as virulence factors in this economically important disease indicates that improving wheat resistance to trichothecenes may provide improved resistance to Fusarium WHS.