Submitted to: AACC International
Publication Type: Abstract Only
Publication Acceptance Date: 6/6/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: N/A Abstract Only
Technical Abstract: The low molecular weight glutenin subunits (LMW-GSs) are a class of wheat seed storage proteins directly involved in the formation of gluten. Depending on the first amino acid residue of the mature proteins, the LMW-GSs are divided into methionine, serine or isoleucine type. These proteins are encoded by a multigene family located at the Glu-3 loci, on the short arm of the homoeologous group 1 chromosomes, and their allelic variation strongly influences wheat end-use quality. However, due to difficulties in the unequivocal LMW-GS allele nomenclature, utilization of a protein-based allele nomenclature system and presence of Glu-3 intralocus recombination, a clear relation between specific LMW-GS alleles and wheat end-use quality parameters has not been established. In the present study, a set of elite hard spring, hard winter and soft spring common wheat varieties was analyzed for their LMW-GS genic profile. These varieties were grown in multiple locations and were extensively evaluated for their end-use quality by flour SDS sedimentation volume, SRC lactic acid, mixograph and extensibility analysis, loaf volume and cookie diameter. The LMW-GS genic profile was analyzed by using a PCR-based molecular marker system that allows the identification of most of the LMW-GS genes present in each common wheat variety. Successively, association between each LMW-GS gene/haplotype and the analyzed end-use quality parameters was investigated. This is the first study where variation in the LMW-GS gene family members, rather than variations of the LMW-GS protein alleles, are associated with wheat end-use quality. Generally, variation at the Glu-A3 locus had a major impact on the analyzed parameters, followed by the Glu-B3 and Glu-D3 loci, in that order. Specifically, among the LMW-GS genes located at the Glu-A3 locus, the ones encoding for the isoleucine-type LMW-GSs had major impact on both dough strength and elasticity, and bread loaf volume. In contrast, at the Glu-B3 locus, the genes encoding the serine-type LMW-GSs had a major impact on dough rheology parameters. At the Glu-D3 locus, allelic variation of a gene encoding for a methionine-type LMW-GS was the most highly associated with both Mixograph and extensibility parameters, and baking properties. These results clearly indicate that there are specific LMW-GS genes/haplotypes more associated than others to variation of dough strength, extensibility and baking properties suggesting the possibility to refine the already existing Glu-3 molecular markers and to develop new molecular markers to more accurately control and improve wheat quality.