Transcriptional networks shaping malting quality in barley: From grain development to brewing performance

Barley (Hordeum vulgare L.) is a cornerstone of the malting and brewing industry, yet the molecular regulation of its key quality traits remains incompletely understood. While the biochemical mechanisms governing starch metabolism, storage protein turnover, β-glucan remodeling, and hydrolytic enzyme activity are well characterized, the transcriptional networks orchestrating these processes during grain development and germination remain less defined. This review hypothesises that transcription factors (TFs) serve as central regulatory hubs, integrating hormonal signals with metabolic pathways to modulate malting quality. Advances in functional genomics, transcriptomics, and network biology increasingly support this model, highlighting the roles of MYB (e.g., GAMYB), DOF, bZIP, NAC, WRKY, and AP2/ERF TFs in regulating starch biosynthesis, endosperm protein dynamics, cell wall degradation, and enzyme induction, particularly under gibberellin-abscisic acid crosstalk. Multi-omics integration, weighted gene co-expression network analysis, and natural allelic variation have identified key regulatory modules associated with malt extract yield, fermentability, free amino nitrogen, and wort viscosity. These insights offer promising targets for genome editing, predictive breeding, and synthetic modulation of malting pathways. By linking TF biology to critical brewing performance traits, this review presents a mechanistic framework for leveraging these findings to develop climate-resilient barley cultivars with consistent and enhanced malting quality, paving the way for innovations in malting science.