Molecular Characterization of Novel x-Type HMW Glutenin Subunit 1B × 6.5 in Wheat

A novel high molecular weight glutenin subunit encoded by the Glu-1B locus was identified in the French genotype Bagou, which we named 1B × 6.5. This subunit differed in SDS-PAGE from well-known 1B × 6 and 1B × 7 subunits, which are also encoded at this locus. Subunit 1B × 6.5 has a theoretical molecular weight of 88,322.83 Da, which is more mobile than 1B × 6 subunit, and isoelectric point (pI) of about 8.7, which is lower than that for 1B × 6 subunit. The specific primers were designed to amplify and sequence 2476 bp of the Glu-1B locus from genotype Bagou. A high level of similarity was found between the sequence encoding 1B × 6.5 and other x-type encoding alleles of this locus.

Polymorphism of high-molecular-weight glutenin loci in Ukrainian wheat landraces Triticum aestivum L.

Aim. The aim of the study was to investigate allelic variability of high-molecular-weight glutenin loci Glu-A1, Glu-B1, Glu-D1 in Ukrainian winter wheat landraces and obsolete cultivars Triticum aestivum L. Methods. Allelic diversity at the Glu-1 loci were analyzed in 54 collection accessions, including 41 landraces (Krymka, Banatka, Girka, Theyka and others), and 13 first breeding cultivars that were developed in the beginning of the last century by selection from local wheat. Method of SDS-PAG electrophoresis according to Laemmli was used for fractionation of HMW glutenin subunits. Results. A total 11 alleles at the Glu-1 loci were identified, including 3 alleles at the Glu-A1 (a, b, c) and Glu-D1 (a, b, d) loci, and 5 – at the Glu- B1 (c, u, an, aj and subunit 9). Differences in frequencies of glutenin alleles were revealed. Conclusions. In the gene pool of Ukrainian winter bread wheat landraces the most widespread alleles were Glu-A1a (43.3 %), Glu-A1b (40.5 %), Glu-B1c (58 %), Glu-B1u (23 %), Glu-D1d (48.6 %), Glu-D1a (47.2 %). All these alleles (except of the Glu-D1a) are also predominant in the gene pool of modern commercial Ukrainian cultivars. A distinctive feature of Ukrainian landraces are the rare allelic variants of the Glu-B1 locus, which encode the subunits 1By9 and 1By8 (allele Glu-B1aj). Keywords: Triticum aestivum L., winter wheat, landraces, high-molecular-weight glutenin, alleles.

Pyramiding of Genes for Grain Protein Content, Grain Quality and Rust Resistance in Eleven Indian Bread Wheat Cultivars: A Multi-Institutional Effort

Improvement of grain protein content (GPC), loaf volume and resistance to rusts was achieved in 11 Indian wheat cultivars that are widely grown in four different agro-climatic zones of India. This involved use of marker-assisted backcrossing (MABC) for introgression and pyramiding of the following genes: (i) the high GPC gene Gpc-B1; (ii) HMW glutenin subunits 5 + 10 at Glu-D1 loci, and (iii) rust resistance genes, Yr36, Yr15, Lr24 and Sr24. GPC was improved by 0.8–3.3%, although high GPC was generally associated with yield penalty. Further selection among high GPC lines, allowed development of progenies with higher GPC associated with improvement in 1000-grain weight and grain yield in the following four cultivars: NI5439, UP2338, UP2382 and HUW468. The high GPC progenies (derived from NI5439) were also improved for grain quality using HMW glutenin subunits 5 + 10 at Glu-D1 loci. Similarly, progenies combining high GPC and rust resistance were developed in the backgrounds of following five cultivars: Lok1, HD2967, PBW550, PBW621 and DBW1. The improved pre-bred lines developed during the present study should prove useful for development of cultivars with improved nutritional quality associated with rust resistance in future wheat breeding programmes.

Proteomic Analysis of Proteins Responsive to Drought and Low Temperature Stress in a Hard Red Spring Wheat Cultivar

Drought stress is becoming more prevalent with global warming, and has been shown to have large effects on gluten proteins linked to wheat bread making quality. Likewise, low temperature stress can detrimentally affect proteins in wheat. This study was done to determine the differential abundance of high molecular weight (HMW) glutenin proteins in a drought and low temperature stressed high quality hard red spring wheat cultivar (PAN3478), against a control. The treatments were applied in the greenhouse at the soft dough stage. HMW glutenin proteins were extracted from the flour, and were separated by using two-dimensional gel electrophoresis. Protein spots that had p values lower than 0.05 and fold values equal to or greater than 1.2 were considered to be significantly differentially abundant. These proteins were further analyzed by using tandem mass spectrometry. There was a 1.3 to 1.8 fold change in 17 protein spots due to the cold treatment. The drought treatment caused a 1.3 to 3.8 fold change in 19 protein spots. These spots matched either HMW or low molecular weight (LMW) glutenin subunits. In the latter case, the C subunits of LMW glutenins were notably found to be up-regulated under both stress conditions. All the proteins that have been identified can directly influence dough characteristics. Data are available via ProteomeXchange with the identifier PXD017578.

Quantification of Wheat, Rye, and Barley Gluten in Oat and Oat Products by ELISA RIDASCREEN® Total Gluten: Collaborative Study, First Action 2018.15

Background: Since its introduction to the analytical community, the R5 method to quantify gluten led to a strong improvement of the situation for the food industry and celiac patients. During recent years, some questions arose on the use of the Codex Alimentarius factor of two to convert from prolamins to gluten, an overestimation of rye and barley, inadequate detection of glutelins, and the inhomogeneous distribution of gluten in oats. These limitations of the R5 method, especially when measuring oat samples, led to AOAC Standard Method Performance Requirement (SMPR®) 2017.021, which was approved by stakeholders in 2017. Objective: We present a collaborative study of a method for the quantitative analysis of wheat, rye, and barley gluten in oat and oat products using a sandwich ELISA that is based on four different monoclonal antibodies including the R5 monoclonal anitbody. Methods: The sandwich ELISA detects intact gliadins and related prolamins from rye and barley, high-molecular-weight (HMW) glutenin subunits (GS) from wheat, HMW secalins from rye, and low-molecular-weight (LMW) GS from wheat. It does not detect D-hordeins from barley. Samples are extracted by Cocktail solution, subsequently followed by 80% ethanol, and analyzed within 50 min. Results: The measurement range is between 5 and 80 mg/kg gluten using a calibrator made out of a gluten extract from four different wheat cultivars. The results of the collaborative test with 19 participating laboratories showed recoveries ranging from 99 to 137% for all three grain sources. Relative reproducibility SDs for samples >10 mg/kg gluten ranged from 10 to 53%. Conclusions: The collaborative study results confirmed that the method is accurate and suitable to measure gluten from all three grain sources and has demonstrated performance on oat matrices, which meets the criteria as specified in SMPR 2017.021. Data from in-house validation experiments are available as Annex B to this publication.

Genetic variability of the storage protein loci in the european winter common wheat varieties licensed for growing in Ukraine

Aim. The aim of the study was to investigate genetic variability of storage protein loci in European common winter wheat varieties licensed for growing in Ukraine in 2018 year. Methods. SDS and APAG electrophoresis were used to identify genotypes at the high-molecular-weight (HMW) glutenin loci Glu-1 and gliadin loci Gli-1. Results. Genotypes at the gliadin loci Gli-A1, Gli-B1, Gli-D1 and HMW glutenin loci Glu-A1, Glu-B1, Glu-D1 were identified in 48 winter common wheat varieties. A total of twenty gliadin alleles (including 10 at the Gli-A1, 4 at the Gli-B1, 6 at the Gli-D1 loci) and eleven HMW-GS alleles (including 3 at the Glu-A1, 5 at the Glu-B1, 3 at the Glu-D1 loci) were revealed. Differences in frequencies of alleles at storage protein loci were established. Conclusions. The high level of allelic variation was observed at the Gli-1 and Glu-1 loci in European common winter wheat varieties. Predominant alleles were revealed: Gli-A1о, Gli-A1а, Gli-A1f, Gli-B1f, Gli-D1b, Gli-D1d, Glu-А1c, Glu-А1a, Glu-B1с, Glu-B1d, Glu-D1d, Glu-D1a. Differences in frequencies of alleles at the storage protein loci between European and Ukrainian common winter wheat varieties were found. Keywords: Triticum aestivum L., winter wheat, storage protein, alleles.