Redox-dependent interaction between thaumatin-like protein and β-glucan influences malting quality of barley

Significance The process of malting in the making of beer is under fine biological regulation. Here, we report the dissection of a malting quality quantitative trait locus (QTL) known for its association with variation in the yield of β-glucan and malt extract. A key gene, HvTLP8 , has been identified in the QTL2 region that is expressed differentially in barley malt and feed varieties, based on analyses of both mRNA and protein. The present finding that the affinity of recombinant HvTLP8 for insoluble barley β-glucan is redox-dependent suggests a key role for redox in the malting process. This discovery represents a significant step forward in understanding the biochemistry of malting.