Disentangling hydroxynitrile glucoside biosynthesis in a barley (Hordeum vulgare) metabolon provides access to elite malting barleys for ethyl carbamate-free whisky production.

Barley produces several specialized metabolites, including five α-, β-, and γ-hydroxynitrile glucosides (HNGs). In malting barley, presence of the α-HNG epiheterodendrin gives rise to undesired formation of ethyl carbamate in the beverage production, especially after distilling. Metabolite-GWAS identified QTLs and underlying gene candidates possibly involved in the control of the relative and absolute content of HNGs, including an undescribed MATE transporter.