Wheat Resistances to Fusarium Root Rot and Head Blight Are Both Associated with Deoxynivalenol- and Jasmonate-Related Gene Expression.

Fusarium graminearum is a major pathogen of wheat causing Fusarium head blight (FHB). Its ability to colonize wheat via seedling root infection has been reported recently. Our previous study on Fusarium root rot (FRR) has disclosed histological characteristics of pathogenesis and pathogen defense that mirror processes of spike infection. Therefore, it would be interesting to understand whether genes relevant for FHB resistance are induced in roots. The concept of similar-acting defense mechanisms provides a basis for research at broad Fusarium resistance in crop plants. However, molecular defense responses involved in FRR as well as their relation to spike resistance are unknown. To test the hypothesis of a conserved defense response, a candidate gene expression study was conducted to test the activity of selected prominent FHB defense-related genes in seedling roots, adult plant roots, spikes, and shoots. FRR was examined at seedling and adult plant stages to assess age-related pattern of disease and pathogen resistance. This study offers first evidence for a significant genetic overlap in root and spike defense responses, both in local and distant tissues. The results point to plant development-specific rather than organ-specific determinants of resistance, and suggest roots as an interesting model for studies on wheat-Fusarium interactions.