Characterisation of a Major QTL For Dietary Fibre in Hexaploid Wheat Using the Watkins collection of Landraces

Brett, James Alex (2024) Characterisation of a Major QTL For Dietary Fibre in Hexaploid Wheat Using the Watkins collection of Landraces. Doctoral thesis, University of East Anglia.

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Abstract

Wheat is the third most widely produced crop globally, and the foods made from it are major staples. 70% of bread sales in the UK are for white bread, primarily due to the low cost and palatability compared to whole grain bread. Arabinoxylan (AX) is the primary dietary fibre in wheat and has a complex biosynthesis. Many QTLs have been identified in various crosses, but few have produced molecular markers that predict high AX for breeding programs. The Watkins landrace collection represents a valuable source of novel genetic diversity absent from elite wheat cultivars. Here I describe in this project the phenotyping of total (TOT) and water extractable (WE) arabinoxylan in three Paragon x Watkins recombinant inbred (RIL) populations, grown over three consecutive years. A QTL analysis was performed, identifying a robust QTL on chromosome 1BL, associated with wholegrain WE-AX. Presence and Absence variation of gene content was determined in the 1B QTL using the Wheat10+ pangenome, and the QTL boundary was reduced, using a bulked segregant analysis. Candidate genes were identified, utilising paired end RNA-seq data from Yumai34 and Valoris, mapped to the 1B chromosome of Paragon, where Yumai34 shares 1B high allele with Paragon. A differential gene expression analysis was performed using the DESEQ2 pipeline, and SNP variants were called to determine expression and SNP differences between Yumai34 and Valoris, in comparison with Paragon. Finally, variants were called for each of the 30 Watkins accessions against the Paragon 1B chromosome using raw sequencing reads derived from the Watseq project. KASP markers have been developed for these candidate genes and may provide breeders with more accurate markers for use in breeding programmes, to achieve higher AX commercial wheat varieties. I also describe various putative mechanisms for each candidate, which may affect AX concentration in wheat grain.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	03 Jun 2025 07:47
Last Modified:	03 Jun 2025 07:47
URI:	https://ueaeprints.uea.ac.uk/id/eprint/99380
DOI:

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