Abstract text: Arabinoxylan (AX) is the major hemicellulose and dietary fibre (DF) in wheat endosperm. Increasing soluble dietary fibre (SDF) in wheat is a promising strategy to increase SDF intake for improved health. However, the specific genetic mechanisms underlying variations in SDF content in wheat remain poorly understood.

We have identified a high SDF allele on chromosome 6B, linked to a peroxidase gene variant with a single residue change (PER1-v), which is associated with reduced dimerisation of ferulate moieties on AX. The change causes the PER1-v protein to not localise properly in the plant cell wall, which showed reduced dimerisation of endosperm ferulate, consistent with a mechanism of decreased cross-linking in the cell wall that increases the amount of water-extractable AX.

The combination of RNA sequencing, genetic and biochemical analyses was employed to demonstrate that the PER1-v allele leads to decreased cross-linking in the cell wall, resulting in higher water-extractable AX.

The PER1-v variant is a perfect marker for breeding wheat varieties with enhanced SDF content, which could significantly contribute to healthier wheat-based foods with increased nutritional quality, and potentially reduce the risk of chronic diseases associated with low dietary fibre intake.

Mitchell et al., 2026, Plant Biotechnol. J