Identification of a major QTL and associated molecular marker for high arabinoxylan fibre in white wheat flour.

Dietary fibre (DF) has multiple health benefits and wheat grains are major sources of DF for human health. However, DF is depleted in white wheat flour which is more widely consumed than wholegrain. The major DF component in white flour is the cell wall polysaccharide arabinoxylan (AX). We have identified the Chinese wheat cultivar Yumai 34 as having unusually high contents of AX in both water-soluble and insoluble forms. We have therefore used populations generated from crosses between Yumai 34 and four other wheat cultivars, three with average contents of AX (Ukrainka, Altigo and Claire) and one also having unusually high AX (Valoris), in order to map QTLs for soluble AX (determined as relative viscosity of aqueous extracts of wholemeal flours) and total AX (determined by enzyme fingerprinting of white flour). A number of QTL were mapped, but most were only detected in one or two crosses. However, all four crosses showed strong QTLs for high RV/total AX on chromosome 1B, with Yumai 34 being the increasing parent, and a KASP marker for the Yumai 34 high AX allele was validated by analysis of high AX lines derived from Yumai 34 but selected by biochemical analysis. A QTL for RV was also mapped on chromosome 6B in Yumai 34 x Valoris, with Valoris being the increasing allele, which is consistent with the observation of transgressive segregation for this population. Association studies in an independent germplasm panel identified marker trait associations for relative viscosity in these same locations while direct selection for fibre content in breeding resulted in high levels of enrichment for the Yumai 34 1B allele. The data therefore indicate that marker-assisted breeding can be used to develop wheat with high AX fibre in white flour.

Data set of enzyme fingerprinting of dietary fibre components (arabinoxylan and ß-glucan) in old and modern Italian durum wheat genotypes.

The data presented are related to the research article entitled "Comparison of the dietary fibre composition of old and modern durum wheat (Triticum turgidum spp. durum) genotypes" (De Santis et al., 2018) [1]. This article provides details of the structures of the major dietary fibre components, arabinoxylan and ß-glucan, in semolina and wholemeal flour of old and modern Italian durum wheat genotypes grown in two seasons, determined by enzyme digestion followed by high-performance anion-exchange chromatography (enzyme fingerprinting).

Comparison of the dietary fibre composition of old and modern durum wheat (Triticum turgidum spp. durum) genotypes.

It has been suggested that intensive breeding has led to decreased contents of health-promoting components in modern wheats. We therefore compared the contents and compositions of the major dietary fibre components, arabinoxylan and ß-glucan, in semolina and wholemeal flour of old and modern Italian durum wheats. No differences in total arabinoxylan content were observed but the modern varieties had higher proportions of soluble arabinoxylan in wholemeals and of ß-glucan in semolina. The study therefore provides no evidence that intensive breeding has had negative effects on the contents of dietary fibre components in durum wheat. However, comparison of material grown over two years indicated that the content and composition of arabinoxylan and ß-glucan were more stable in the older than in the modern genotypes. The identification of modern cultivars with high viscosity associated with a high content of ß-glucan suggests that they are good sources of fibre for human health.