Genetic exploration of β -glucan content in barley grains through GWAS and RNA-sequencing approaches

Rapid advancements in molecular-level studies have highlighted significant changes and challenges in plant genetic studies. The current research on barley germplasm in China has shed light on the genetic mechanisms behind β-glucan content. In this study, the genotypic variation for 260 barley accessions was examined, with mean β-glucan values ranging from 3.22% to 5.48% across five environments. A genome-wide association study (GWAS) using a general linear model (GLM) identified 55 significant SNP markers on chromosomes 1 H, 3 H, 4 H, 5 H, 6 H, and 7 H, explaining 7.35% to 15.94% of the observed phenotypic variation. Transcriptome sequencing was performed on two contrasting germplasms, revealed 1,880 and 1,160 differentially expressed genes (DEGs) at 14 and 28 days post-anthesis, respectively, with pathways enriched in starch and sucrose metabolism, linking them to β-glucan variation. A new gene, newGene_23124 (1 H), was identified with a functional annotation as a beta-D-glucan exohydrolase was identified as a strong candidate gene. GWAS results identified foundglycosyltransferase family protein genes, HORVU.MOREX.r3.1HG0057970 (1 H), and HORVU.MOREX.r3.3HG0279880 (3 H), which are involved in β-glucan synthesis and cell wall formation. Additionally, the genes HORVU.MOREX.r3.4HG0337820 (4 H) and HORVU.MOREX.r3.5HG0431360 (5 H), encoding for UDP-glycosyltransferase family proteins, were also identified. Furthermore, HORVU.MOREX.r3.7HG0651610 (7 H), encoding a glycosyl hydrolase family 10 protein, was found to influence β-glucan content. In addition to these, several other genes were investigated. Overall, this research provides new insights into the genetic regulation of β-glucan content in barley and lays the foundation for breeding programs aimed at nutritional improvement of the crop.

The online version contains supplementary material available at 10.1007/s11032-025-01625-6.