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

## TL;DR

This review explores how transcription factors regulate key processes in barley that affect malting and brewing quality, offering new targets for improving barley through genetic methods.

## Contribution

The paper identifies transcription factor networks as central regulators of malting quality traits, providing a framework for targeted genome editing and breeding.

## Key findings

- Transcription factors like MYB, DOF, and bZIP regulate starch and β-glucan metabolism during malting.
- Hormone-responsive TF modules control germination timing and enzyme activity, impacting malt quality.
- Multi-omics approaches reveal genome editing targets to improve fermentability and brewing performance.

## Abstract

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.

•TF networks regulate starch mobilization and β-glucan breakdown, shaping malting efficiency.•Regulatory hubs identified as key drivers of malt extract yield and overall fermentability.•Hormone-responsive TF modules orchestrate germination timing and enzyme induction dynamics•Genome editing targets revealed to enhance malting quality and brewing performance outcomes.

TF networks regulate starch mobilization and β-glucan breakdown, shaping malting efficiency.

Regulatory hubs identified as key drivers of malt extract yield and overall fermentability.

Hormone-responsive TF modules orchestrate germination timing and enzyme induction dynamics

Genome editing targets revealed to enhance malting quality and brewing performance outcomes.