| Fusarium graminearum is a globally distributed fungal pathogen that causes disease in cereal crops such as wheat and barley and it also contaminates host plants with a secreted mycotoxin known as deoxynivalenol. Consumption of infected or contaminated cereal products is hazardous to animals, therefore, fungal infection and contamination cause major economic losses in agriculture industries worldwide. My thesis project focused on characterizing two positive regulators, Tri10 and Tri6, of the trichothecene biosynthesis pathway in F. graminearum. Gene expression profiling of Tri10Delta and Tri6 Delta mutant strains under DON-inducing conditions provided evidence that the regulatory roles of the two studied genes extend beyond the trichothecene biosynthesis pathway. They are potential regulators of another clustered secondary metabolic pathway, butenolide synthesis pathway, and also genes involved in primary metabolism. In contrast to a prior regulatory model of the trichothecene biosynthesis pathway, RNA transcript analysis demonstrated that regulation of Tri10 and Tri6 gene expressions are independent of each other. The distinct gene sets regulated by Tri10 and Tri6 indicate different, albeit overlapping, roles in regulating gene expression. |
