Identification of the Key Transcription Factors Regulating the Expression of the Genes Associated with Barley Malt Quality during Malting.

Barley malt is produced through a malting process; it begins with steeping followed by germination and kilning, in which dramatic changes happen for a large number of physiological and biochemical traits in barley seeds. The objectives of this study were to comprehensively investigate the phenotypic changes during malting, and identify the key regulators that modulate the expression of genes associated with malt quality traits. The results showed that there was a significant positive correlation between gibberellic acid (GA) content and the activities of some hydrolytic enzymes, including α-amylases, β-amylases, and limit dextrinase (LD), and a significant negative correlation between GA and β-glucan content. Starch content had little change, but starch granules were pitted severely during malting. Weighted gene coexpression analysis (WGCNA) identified the genes associated with the greatest changes of the examined malt traits during malting. The correlation analysis and protein-protein interaction (PPI) analysis detected several key transcriptional factor (TF) regulating genes associated with malt quality. These genes and TFs regulating malting traits are potentially useful in barley breeding for malt quality improvement.