Influence of Fusarium isolates on the expression of barley genes related to plant defense and malting quality

• Barley gene expression is altered by Fusarium infection both before harvest and during malting.
• Genes important for future malting quality are altered shortly after Fusarium infection.
• This study increases understanding of barley transcriptional responses to Fusarium.
• Effective Fusarium control is important to secure high quality malt.

Fusarium head blight (FHB) is a significant fungal disease of barley implicated in various brewing-related disorders and could further influence the expression of genes related to malting quality. The aim of our research was to improve understanding of barley gene regulation in FHB-infected grain over time, starting from the onset of infection on flowering spikes, right up to preparation of finished malt. Two two-rowed spring barley varieties (Grace and Scarlett) were infected with species-specific spore suspensions of Fusarium culmorum, Fusarium avenaceum, Fusarium langsethiae, or Fusarium sporotrichioides under greenhouse conditions. We selected a subset of barley gene candidates related to plant defense and to malting quality traits for our gene expression analyses. We further complemented this by measuring the Fusarium DNA content in the same samples. Our work demonstrates that gene expression is indeed altered by Fusarium infection both before harvest and during malting. This includes increased expression of plant defense genes and differential expression of malting-related genes, in particular the two β-amylase genes, α-amylase and α-amylase/trypsin inhibitor. This research increases the understanding of transcriptional changes in barley grain in response to different Fusarium species and emphasizes the importance of Fusarium control before harvest for securing high quality malt.