GWAS reveals the genetic complexity of fructan accumulation patterns in barley grain

We profiled the grain oligosaccharide content of 154 two-row spring barley genotypes and quantified 27 compounds, mainly fructans, that exhibited differential abundance. Clustering revealed two major profile groups where the 'high' set contained greater amounts of sugar monomers, sucrose a...

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Bibliographic Details
Published inbioRxiv
Main Authors Matros, Andrea, Houston, Kelly, Tucker, Matthew R, Schreiber, Miriam, Berger, Bettina, Aubert, Matthew K, Wilkinson, Laura G, Witzel, Katja, Waugh, Robbie, Seiffert, Udo, Burton, Rachel Anita
Format Paper
LanguageEnglish
Published Cold Spring Harbor Cold Spring Harbor Laboratory Press 29.06.2020
Subjects
Barley
Biosynthesis
Fructosyltransferase
Genes
Genotypes
Inulin
Monomers
Oligosaccharides
Single-nucleotide polymorphism
Sucrose
Transcription factors
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Summary:We profiled the grain oligosaccharide content of 154 two-row spring barley genotypes and quantified 27 compounds, mainly fructans, that exhibited differential abundance. Clustering revealed two major profile groups where the 'high' set contained greater amounts of sugar monomers, sucrose and overall fructans, but lower fructosylraffinose. GWAS identified a significant association for the variability of two fructan types; neoseries-DP7 and inulin-DP9 which showed increased strength when a compound-ratio GWAS was applied. Gene models within this region included five fructan biosynthesis genes, of which three (fructan:fructan 1-fructosyltransferase, sucrose:sucrose 1-fructosyltransferase, and sucrose:fructan 6-fructosyltransferase) have already been described. The remaining two, 6(G)-fructosyltransferase and vacuolar invertase1 have not previously been linked to fructan biosynthesis in barley and showed expression patterns distinct from those of the other three genes, including exclusive expression of 6(G)-fructosyltransferase in outer grain tissues at the storage phase. From exome capture data several SNPs related to inulin- and neoseries-type fructan variability were identified in fructan:fructan 1-fructosyltransferase and 6(G)-fructosyltransferase genes Co-expression analyses uncovered potential regulators of fructan biosynthesis including transcription factors. Our results provide evidence for the distinct biosynthesis of neoseries-type fructans during barley grain maturation plus new gene candidates likely involved in the differential biosynthesis of the various fructan types.
DOI:10.1101/2020.06.29.177881