Impact of trichothecenes on Fusarium head blight [Fusarium graminearum] development in spring wheat (Triticum aestivum)

Fusarium head blight pathogens (Fusarium spp.) produce trichothecenes that have been demonstrated to play a role in the pathogenesis. To test the impa ct of trichothecenes on a broad range of genotypes, 18 spring wheat lines ( Triticum aestivum) were inoculated with two Fusarium graminearum strains, t he genetically modified GzT40 strain, which could not produce trichothecene , and the wild parental Gz3639 strain. During 3 weeks of observation, the t wo fungal strains showed extreme differences in aggressiveness in all but t hree of wheat genotypes tested. While the GzT40 mutant did not spread into the rachis, the wild-type strain quickly spread in the spike. This work con firms earlier findings that trichothecenes are a principal determinant of F . graminearum aggressiveness on most spring wheat cultivars. Therefore, tri chothecenes may serve as a useful screening tool in programs breeding for r esistance to Fusarium head blight of wheat.