Project description:European common ash, Fraxinus excelsior L., is currently threatened by Ash dieback (ADB) caused by the fungus, Hymenoscyphus fraxineus. To detect and identify metabolites that may be products of pathways important in contributing to resistance against H. fraxineus we performed untargeted metabolomic profiling on leaves from selected F. excelsior individuals showing strong tolerance or susceptibility to H. fraxineus. We identified sets of "features" [small molecules] that enabled strong discrimination between tolerant or susceptible genotypes of F. excelsior. Strikingly, tolerant F. excelsior lines exhibited low levels of iridoid glycosides, known anti-feeding deterrents. As Europe is threatened by Emerald Ash Borer (Agrilus planipennis), an invasive wood boring beetle native to East Asia that has devastated North American ash, our study raises the question whether selection for resistance to H. fraxineus leads to ecological trade-offs that result in susceptibility to emerging pests such as emerald ash borer.
