The Barley Glycosyltransferase Gene KOB1 Implicated in β-Glucan Biosynthesis by a Genome-Wide Association Study

TL;DR

This study identifies the KOB1 gene in barley as a key player in β-glucan biosynthesis, which is important for food and feed quality.

Contribution

The study functionally characterizes KOB1, a glycosyltransferase gene, as a regulator of β-glucan content in barley.

Findings

Haplotype E of KOB1 is associated with higher grain β-glucan levels in barley.

Overexpression of KOB1 in rice increases grain β-glucan content significantly.

KOB1 is confirmed to play a critical role in β-glucan biosynthesis.

Abstract

β-glucan, a crucial trait in barley breeding programs, serves as a quality determinant of products intended for both human consumption and animal feed. Although genes involved in β-glucan synthesis have been reported, the genetic mechanisms regulating its accumulation in barley grain remain underexplored. In this study, we functionally characterized KOB1, a candidate gene identified from a genome-wide association study (GWAS) on barley seed β-glucan content, which encodes a glycosyltransferase. Haplotype analysis showed that haplotype E was associated with significantly elevated grain β-glucan levels compared to other haplotypes. Furthermore, overexpression of KOB1 in rice led to a significant increase in grain β-glucan content relative to the wild-type Zhonghua 11, confirming its critical role in β-glucan biosynthesis. Our findings establish the glycosyltransferase gene KOB1 as a valuable genetic resource for molecular breeding programs aimed at improving grain β-glucan content.

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