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 impact of trichothecenes on a broad range of genotypes, 18 spring wheat lines (Triticum aestivum) were inoculated with two Fusarium graminearum strains, the genetically modified GzT40 strain, which could not produce trichothecene, and the wild parental Gz3639 strain. During 3 weeks of observation, the two fungal strains showed extreme differences in aggressiveness in all but three 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 confirms earlier findings that trichothecenes are a principal determinant of F. graminearum aggressiveness on most spring wheat cultivars. Therefore, trichothecenes may serve as a useful screening tool in programs breeding for resistance to Fusarium head blight of wheat.