Ash dieback epidemic in Europe: How can molecular technologies help?

The fungal pathogen  Hymenoscyphus fraxineus that infects European ash (Fraxinus excelsior) has caused a huge epidemic and cost millions of trees their lives. Downie describes the employment of molecular techniques to trace the origin of the fungus in Europe, and describes how the fungal life cycle contributes to pathogen diversity.  He also describes the associative transcriptomics approach that has been used to identify genetic markers linked to pathogen susceptibility. By sequencing RNA from individuals with varying levels of susceptibility, changes in gene expression levels (GEMs, gene expression markers) and SNPs (single nucleotide polymorphisms) correlated with lower susceptibility were identified.  The author observes that associated transcriptomics can be useful for combating other pests, including the insect pest emerald ash borer (Agrilus planipennis). PLOS Pathogens 10.1371/journal.ppat.1006381