Biology subjects

Shewry, P. R.

Publications and source records attributed to Shewry, P. R..

3 recordsLinked to original sources

bioRxiv2026

Genetic architecture of soluble arabinoxylan fibre in elite genotypes of bread wheat revealed by genome-wide association analysis

Dietary fibre intake remains below recommended levels, and increasing fibre content of widely consumed white wheat flour (derived from the starchy endosperm) represents a scalable strategy to improve public health. In wheat starchy endosperm, arabinoxylan (AX) is the dominant fibre component, with the water-extractable (WE) fraction being particularly beneficial to health. We assembled an Elite Fibre Panel (EFP) of 384 elite modern wheat genotypes from UK commercial breeding programmes and quantified the content of WE-AX in wholemeal, as a proxy for soluble AX in white flour, across two UK field environments. Wholemeal WE-AX, showed substantial quantitative variation and moderate genotype-by-environment interaction, with a broad-sense heritability of 0.68. Genome-wide association analyses using 6,791 SNPs identified seven loci associated with WE-AX content. The strongest and most stable effects were mapped to major loci on chromosomes 1B and 6B, previously implicated in AX regulation, while additional loci of smaller and sometimes environment-dependent effect were detected on chromosomes 3A, 5B, and 7A. Favourable alleles increased WE-AX content by [~]5-15% and combined additively. LD-defined intervals contained several high-confidence candidate genes involved in cell-wall biosynthesis, remodelling and post-depositional modification, including PER1, a validated regulator of arabinoxylan cross-linking, together with genes encoding a UTP-glucose-1-phosphate uridylyltransferase, trichome birefringence-like proteins and xyloglucan endotransglucosylase/hydrolases. These findings demonstrate that substantial gains in soluble AX can be achieved by pyramiding favourable alleles already segregating within elite germplasm, providing a practical route for breeding wheat with enhanced dietary fibre content and improved nutritional quality. Key messageMultiple additive loci controlling soluble arabinoxylan content were identified in elite wheat germplasm, enabling marker-assisted breeding for increased dietary fibre in white flour.

genomics↗

bioRxiv2023

A high soluble-fibre allele in wheat encodes a defective cell wall peroxidase responsible for dimerization of ferulate moieties on arabinoxylan

Increasing dietary fibre (DF) intake is an important target to improve health and an attractive strategy for this is to increase the fibre content of staple foods, particularly white bread which is the staple food in many countries. DF in wheat white flour is derived principally from the endosperm cell wall polysaccharide arabinoxylan (AX) and the water-extractable form of this (WE-AX) accounts for the majority of soluble dietary fibre (SDF), which is believed to confer particular health benefits. We previously identified QTLs for soluble dietary fibre (SDF) on 1B and 6B chromosomes in wheat in biparental populations. Here we show that the 6B high SDF allele encodes a peroxidase protein (PER1-v) with a single missense compared to the more common low SDF form (PER1). Wheat lines with the natural PER1-v allele and with an induced knock-out mutation in PER1 showed similar characteristics of reduced dimerization of ferulate associated with water-extractable WE-AX. Decreased ferulate dimerization is associated with decreased cross-linking of the WE-AX chains and increased solubility of AX. Transiently expressed PER1_RFP fusion driven by native promoter in wheat endosperm was shown to localise to cell walls whereas PER1-v_RFP did not; we therefore propose that PER1-v lacks capacity to dimerise AX ferulate in vivo due to mis-localisation. PER1 is the first peroxidase reported to be responsible for oxidative coupling of ferulate on AX, a key process in all grass cell walls. Understanding its role and the effect of variants on AX properties offers a route to control the properties of wheat DF in the human diet.

plant biology↗

bioRxiv2021

Subcellular dynamics studies reveal how tissue-specific distribution patterns of iron are established in developing wheat grains

Understanding iron trafficking in plants is key to enhancing the nutritional quality of crops. Due to the difficulty of imaging iron in transit, little is known about iron translocation and distribution in developing seeds. A novel approach, combining 57Fe isotope labelling and NanoSIMS, was used to visualize iron translocation dynamics at the subcellular level in wheat grain, Triticum aestivum L. We were able to track the main route of iron from maternal tissues to the embryo through different cell types. Further evidence for this route was provided by genetically diverting iron into storage vacuoles, as confirmed by histological staining and TEM-EDS. Virtually all iron was found in intracellular bodies, indicating symplastic rather than apoplastic transport. Aleurone cells contained a new type of iron body, highly enriched in 57Fe, and most likely represents iron-nicotianamine being delivered to phytate globoids. Correlation with tissue-specific gene expression provides an updated model of iron homeostasis in cereal grains with relevance for future biofortification efforts.

plant biology↗