Genome-wide association study reveals the genetic complexity of fructan accumulation patterns in barley grain

Abstract We profiled the grain oligosaccharide content of 154 two-row spring barley genotypes and quantified 27 compounds, mainly inulin- neoseries-type fructans, showing differential abundance. Clustering revealed two profile groups where ‘high’ set contained greater amounts sugar monomers, sucrose, overall but lower fructosylraffinose. A genome-wide association study (GWAS) identified a significant for variability fructan types: neoseries-DP7 inulin-DP9, which showed increased strength when applying novel compound ratio-GWAS approach. Gene models within this region included three known biosynthesis genes (fructan:fructan 1-fructosyltransferase, sucrose:sucrose sucrose:fructan 6-fructosyltransferase). Two other in region, 6(G)-fructosyltransferase vacuolar invertase1, have not previously been linked to expression patterns distinct from those genes, including exclusive outer tissues at storage phase. From exome capture data, several single nucleotide polymorphisms related were fructan:fructan 1-fructosyltransferase genes. Co-expression analyses uncovered potential regulators transcription factors. Our results provide first scientific evidence fructans during maturation reveal gene candidates likely be involved various types barley.