Fitness of Three Fusarium Pathogens on Oat Genotypes with different levels of resistance to Fusarium Head Blight.

Fusarium head blight (FHB) has become the most important disease affecting Canadian oat industry, which results in not only yield loss but also contaminates oat grains with mycotoxins that are harmful to human and livestock. Deoxynivalenol, produced mostly by Fusarium graminearum, is usually the main trichothecene found in oat grains. However recent surveys in western Canada have indicated that multiple Fusarium species, including F. poae, F. graminearum and F. sporotrichiolodies, could be found in commercial oat fields. The complexity of Fusarium species affecting oat has raised the concern that whether additional mycotoxins could be detected in oat grains and the effectiveness of resistance deployed in current varieties to different Fusarium species. It is also unclear that whether the competition among Fusarium species during the infection will have any impact on the production of mycotoxins. In this study, we evaluate the response of ten oat genotypes to three Fusarium pathogens, including F. poae, F. graminearum and F. sporotrichiolodies. oat plants are inoculated with isolates from different Fusarium species, separately or in combinations. Fusarium DNA in infected plants is quantified using qPCR and mycotoxins produced by these Fusarium isolates in contaminated grains are evaluated. Our preliminary study indicates that F. poae might have a synergistic effect on the virulence of F. graminearum and its production of mycotoxins during the infection process suggesting that F. poae might play an important role in FHB disease complex affecting oat and post a serious threat to Canadian oat industry.