Analysis of EMS Induced High Molecular Weight Glutenin Subunit 1Dx5 and 1Dy10 Alleles in Common Wheat

The high molecular weight glutenin subunit genes (HMW-GS) in wheat (Triticum aestivum L.) play a key role in determining dough functionality. More specifically allelic variation for the Glu-D1 subunit loci is associated with bread making quality. Since much of the hard wheat germplasm is fixed for the 1Dx5+1Dy10 haplotype, our goal was to identify allelic variation in 1Dx5 and 1Dy10 HMW-GS genes using an EMS mutagenized population in the soft white spring wheat cultivar ‘Alpowa’. A second goal was to examine their impact on gluten strength and dough handling properties. Phenotypic screening for gluten strength and direct sequencing of M₂ families was used to identify mutations. Phenotypic screening of M₂ families identified three nonsense and one missense mutation from families with low gluten strength. Direct sequencing showed a mutation discovery density of 1/12.7 kb and identified 135 mutations of which 59% were missense mutations. A subset of missense and nonsense mutants were crossed to the Alpowa parent and dough handling properties were measured from mutant and wild type counterparts from field grown F₂ populations. All nonsense mutations in 1Dx5 and 1Dy10 showed significant loss of function. On average the mutations reduced dough resistance, extensibility, mix time, and increased water absorption but increased flour protein. Three missense mutations were identified that showed increased dough resistance and/or extensibility. Such mutations show promise of expanding the phenotypic variability for these dough traits.