Low Molecular Weight Glutenin Subunits Research Articles

The association of glutenin subunit composition to baking quality traits of spring and winter wheat in Estonia

In Estonian local mills, protein content (PC) and wet gluten content (WGC) are among the main indicators considered and evaluated when purchasing grains. Protein composition also significantly affects baking quality. The baking quality of ten winter wheat (WW) and spring wheat (SW) varieties was studied at the Center of Estonian Rural Research and Knowledge (METK). PC, WGC, gluten index (GI), and dough stability time (DST) were higher in SW varieties. PC was positively correlated with WGC and loaf volume (LV) in both wheat types. PC and WGC were negatively correlated with GI and positively correlated with DST only in WW. The viscoelastic properties of dough are linked to its high- and low molecular weight glutenin subunits (HMW-GS and LMW-GS). The allelic composition of the glutenin genes was determined using DNA markers. All the studied varieties had the allele Glu-D1d and additional allele Glu-D1a was found in the variety ‘Voore’. Fourteen varieties had Glu-A1a and b alleles associated with improved backing quality. Alleles Glu-B1с and Glu-B1b were found in WW varieties. SW varieties carried alleles Glu-B1al, b, с and h. The average QS was higher in SW. Eight varieties had null alleles Glu-A1c, Glu-A3e, and Glu-B3j, which negatively affected bread-making quality.

Molecular Mechanism of Egg White Protein for Strengthening the Cross‐Linking Properties of Heat‐Induced Wheat Gluten Gel

AbstractThe chemical interaction between egg white protein (EWP) and wheat gluten (WG) is significantly influenced by the amount of EWP added. Therefore, the effects of EWP addition on the gelling properties and chemical interactions of heat‐induced WG–EWP gels are thoroughly examined. The results demonstrate that the enhancement in gel strength of WG–EWP gels is positively correlated with the amount of EWP added. EWP addition improves protein–protein interactions by reducing the freedom of water. The enhanced aggregation between WG and EWP is likely due to a decrease in surface hydrophobicity and an increase in β‐sheet content. EWP enhances cross‐linking with low molecular weight glutenin subunit (LMW‐GS), high molecular weight glutenin subunit (HMW‐GS), and gliadin (Gli). Specifically, EWP primarily cross‐links with ω‐, α‐, and γ‐Glis through S–S bonds and interacts with GS through hydrophobic interactions and S–S bonds. This study provides a theoretical foundation for improving the WG network structure in wheat‐based food production.

Quantitative proteomic analysis for characterization of protein components related to dough quality and celiac disease in wheat flour, dough, and heat-treated dough

High-sensitivity 4D label-free proteomic technology was used to identify protein components related to gluten quality and celiac disease (CD) in strong-gluten wheat cultivar KX 3302 and medium-gluten wheat cultivar BN 207. The highly expressed storage protein components in KX3302 were high-molecular-weight-glutenin-subunits (HMW-GSs), α-gliadin, and globulin, whereas those in BN207 were γ-gliadin, low-molecular-weight-glutenin-subunits (LMW-GSs) and avenin-like proteins. In addition, BN207 had more upregulated metabolic proteins than KX3302. The abundance of storage proteins increased during dough formation. After heat treatment, the upregulated proteins accounted for 57.53 % of the total proteins, but the downregulated storage proteins accounted for 79.34 % of the total storage proteins. In cultivar KX3302, CD proteins mainly included α-gliadin and HMW-GSs, whereas in BN207, they were mainly γ-gliadin and LMW-GSs. Thermal treatment significantly reduces the expression levels of CD-related proteins. These findings provide a new perspective on reducing the content of CD-related proteins in wheat products.

Grain albumin content is affected by 1BL/1RS translocation and alters the processing quality of wheat (Triticum aestivum L.).

Grain albumin is highly nutritious and closely related to the processing quality of wheat. However, few studies have explored the grain albumin content (GAC) in wheat. This study aims to uncover quantitative trait loci (QTLs) linked to wheat GAC by analyzing a doubled haploid (DH) population derived from common wheat cultivars ShanNong23 and ZhouMai17. We detected six QTLs controlling GAC on chromosomes 1B, 5A, and 6D, with individual QTL explaining 5.78% to 22.29% of the GAC variation. The effect of QGac.cau-1B.1 on GAC is attributed to the presence of the 1BL/1RS translocation, indicating that the 1BL/1RS translocation increase of GAC compared with the non-1BL/1RS translocation lines. The higher GAC observed in 1BL/1RS lines could be primarily attributed to the increased accumulation of omega-secalin, omega-gliadin, low molecular weight glutenin subunit and ribosomal protein content. Additionally, we also found that the SDS-sedimentation value of whole wheat flour was decreased by adding albumin solution. These results advance our understanding of the genetic basis of GAC and offer novel perspectives for enhancing wheat quality through genetic enhancements.

Image-assisted quantification of high and low molecular weight glutenin fractions in wheat by SDS-PAGE

Gluten quality in bread wheat is mainly determined by gluten strength and protein content. Traditionally gluten quality has been predicted based only on allelic variation for HMW-GS characterized by SDS-PAGE- The ratio of high to low molecular weight glutenin subunits has received less attention despite its influence on gluten properties is acknowledge. That is mainly because accurate quantification of glutenin fractions is made by RP-HPLC, a more complex, expensive and time-consuming technology. In the present study, a methodology to estimate HMW/LMW glutenin subunit ratio by SDS-PAGE results was assessed. We used a segregating population derived from a cross between two Spanish bread wheat landraces (Richela Blanca and Jeja Pardilla) showing striking differences according to SDSS tests. Quantification of prolamins by RP-HPLC confirmed a wide range of variation in the HMW/LMW glutenin subunit ratio within the population. Then, we selected 22 lines that represented the available variation. Subsequently, we obtained high-quality SDS-PAGE images following a standard protocol to characterize glutenin allelic variants. Estimation of HMW/LMW-GS ratio was obtained by analyzing the intensity of HMW-GS and LMW-GS gel bands. Correlation between RP-HPLC and SDS-PAGE values was greater than 0.85 proving the suitability of the much simpler and cheaper electrophoretic-based alternative.

RNA-Seq transcriptome profiling of immature grain wheat is a technique for understanding comparative modeling of baking quality

Improving the baking quality is a primary challenge in the wheat flour production value chain, as baking quality represents a crucial factor in determining its overall value. In the present study, we conducted a comparative RNA-Seq analysis on the high baking quality mutant “O-64.1.10” genotype and its low baking quality wild type "Omid" cultivar to recognize potential genes associated with bread quality. The cDNA libraries were constructed from immature grains that were 15 days post-anthesis, with an average of 16.24 and 18.97 million paired-end short-read sequences in the mutant and wild-type, respectively. A total number of 733 transcripts with differential expression were identified, 585 genes up-regulated and 188 genes down-regulated in the “O-64.1.10” genotype compared to the “Omid”. In addition, the families of HSF, bZIP, C2C2-Dof, B3-ARF, BES1, C3H, GRF, HB-HD-ZIP, PLATZ, MADS-MIKC, GARP-G2-like, NAC, OFP and TUB were appeared as the key transcription factors with specific expression in the “O-64.1.10” genotype. At the same time, pathways related to baking quality were identified through Kyoto Encyclopedia of Genes and Genomes. Collectively, we found that the endoplasmic network, metabolic pathways, secondary metabolite biosynthesis, hormone signaling pathway, B group vitamins, protein pathways, pathways associated with carbohydrate and fat metabolism, as well as the biosynthesis and metabolism of various amino acids, have a great deal of potential to play a significant role in the baking quality. Ultimately, the RNA-seq results were confirmed using quantitative Reverse Transcription PCR for some hub genes such as alpha-gliadin, low molecular weight glutenin subunit and terpene synthase (gibberellin) and as a resource for future study, 127 EST-SSR primers were generated using RNA-seq data.

Rapid analysis of wheat gluten composition using a triple ELISA.

Gluten composition is an important quality parameter of wheat flour. Reversed-phase high-performance liquid chromatography (RP-HPLC) is a state-of-the-art method for its analysis. As this is a very labour-intensive and time-consuming procedure, alternative faster methods are desirable. Enzyme-linked immunosorbent assay (ELISA) is a high-throughput method often used for the analysis of gluten traces in gluten-free products. In this proof-of-principle study, we introduce an experimental triple ELISA for the relative quantitation of gliadins, high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS) of one wheat flour extract. The results of 80 common wheat flour samples obtained from the triple ELISA and RP-HPLC were correlated. The results for gliadins (r = 0.69) and HMW-GS (r = 0.81) showed a medium and high correlation, respectively. Only a very weak correlation of ELISA and RP-HPLC results was observed for LMW-GS (r = 0.49). Results for glutenins (r = 0.69) and gluten (r = 0.72) had a medium correlation. The gliadin/glutenin ratio (r = 0.47) and LMW-GS/HMW-GS ratio (r = 0.40) showed a weak or no correlation. The gliadin, LMW-GS and gluten contents were lower and the HMW-GS content was higher in the ELISA measurement compared to RP-HPLC. The quantitation of gliadins and HMW-GS by the experimental triple ELISA showed comparable results to RP-HPLC, whereas no strong correlation between the results from the two methods was found for LMW-GS. Overall, the experimental triple ELISA is suitable for relative gluten quantitation, especially for the analysis of large sample sets. Further work will focus on improving the experimental procedure of the ELISA. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Glu-A3b allelinin rekombinant kendilenmiş hat popülasyonunda ekmeklik buğdayın gluten kalitesi üzerinde önemli bir etkisi vardır

In this study, a total of 147 wheat lines with variying low molecular weight glutenin subunits (LMW-GS), obtained by crossing Tosunbey and Tahirova2000 bread wheats, were included. Milling, protein, dough-mixing properties of the genotypes were measured and their relations with LMW-GS were investigated in eight different environments. As the LMW-GS of the parents were quite different; milling, protein and dough-mixing properties of the lines were significantly influenced. In this regard, presence of rye translocation (Glu-B3j) reduced flour yield and increased damaged starch and protein contents. In terms of protein quality, Glu-A3b+Glu-B3b allellic combinations were better than GluA3b+Glu-B3j or Glu-A3e +Glu-B3j allellic combinations. It was observed that negative effects of rye translocation could be minimized by selecting proper Glu-3 alleles, such as Glu-A3b instead of Glu-A3e. LMW-GS combinations of the lines influenced mixolab mixing and thermorheological properties. In this respect, the lines with Glu-A3b or Glu-B3b allelles showed increased mixing time and stability as compared to the lines with Glu-A3e or Glu-B3j allelles. The effect of LMW-GS alleles on gluten quality and dough strength was statistically bb > eb > bj > ej. In terms of myxolab stability value related to bread volume; 1 = 2*, 7 + 9 > 17 +18, b > e and b > j; in terms of mixing time; 1 > 2*, 7 + 9 < 17 +18, b > e and b > j. As a result, the Glu-A3b allele can be used to increase gluten quality, and the Glu-B3j allele can be used to increase protein content. Proper allellic combinations of LMW-GS in wheat can be developed for a given bakery product.

Structure Strengthening Phenomena of Gluten Matrices under Different Stress Types.

To predict the achievable product volume with respect to the gas retention capacity of the gluten matrix in wheat flour doughs, strain hardening evaluation is crucial. But assessing these structure hardening phenomena in wheat flour dough systems is still a challenging task. In this work, a simple shear method applied to kneaded dough samples was tested and compared to biaxial extension tests performed with a lubricated squeezing flow method. The comparability of shear-induced structure hardening with biaxial extension tests was shown. Structure hardening and breakdown after overload were visualized using shear flow and a comparison of the obtained shear flow over Hencky strain curve peaks. To predict the behavior of the analyzed flours according to their composition, a correlation analysis of the flour and dough properties was performed. The influence of the HMW glutenin subunits on the sensitivity of the dough matrix according to the applied shear speed (0.1 and 1.0 mm/s) could be shown with a correlation coefficient of 0.94. The LMW glutenin subunits, on the other hand, showed a high correlation coefficient of 0.89 with the achievable network connectivity parameter z [-] gained from frequency sweep testing.

Identifying cis-Acting Elements Associated with the High Activity and Endosperm Specificity of the Promoters of Genes Encoding Low-Molecular-Weight Glutenin Subunits in Common Wheat (Triticum aestivum).

Low-molecular-weight glutenin subunits (LMW-GSs) associated with bread-baking quality and flour nutrient quality accumulate in endosperms of common wheat and related species. However, the mechanism underlying the expression regulation of genes encoding LMW-GSs has not been fully elucidated. In this study, we identified LMW-D2 and LMW-D7, which are highly and weakly expressed, respectively, via the analysis of RNA-sequencing data of Chinese Spring wheat and wheat transgenic lines transformed with 5' deletion promoter fragments and GUS fusion constructs. The 605-bp fragment upstream of the LMW-D2 start codon could drive high levels of GUS expression in the endosperm. The truncated endosperm box located at the -300 site resulted in the loss of LMW-D2 promoter activity, and a single-nucleotide polymorphism on the GCN4 motif was closely related to the expression of LMW-GSs. TCT and TGACG motifs, as well as the others located on the 5' distal end, might also be involved in the transcription regulation of LMW-GSs. In transgenic lines, fusion proteins of LMW-GS and GUS were deposited into protein bodies. Our findings provide new insights into the mechanism underlying the transcription regulation of LMW-GSs and will contribute to the development of wheat endosperm as a bioreactor for the production of nutraceuticals, antibodies, vaccines, and medicinal proteins.

Effects of Low-Molecular-Weight Glutenin Subunit Encoded by Glu-A3 on Gluten and Chinese Fresh Noodle Quality.

Low-molecular-weight glutenin subunits (LMW-GS) account for 40% of the total wheat grain gluten protein fraction, which plays a significant role in the formation of noodle processing quality. The goal of this study was to clarify the effects of the major LMW-GS encoded by Glu-A3 on gluten and Chinese fresh noodle (CFN) quality. Four near-isogenic lines (NILs) were used as materials in this study, respectively carrying alleles Glu-A3a, Glu-A3b, Glu-A3c, and Glu-A3e, against the background of wheat variety Xiaoyan 22. The grain protein and its component contents and the gluten content, gluten index, farinograph properties, cooking quality, and textural quality of CFN were investigated. The results show that the ratios of glutenin to gliadin (Glu/Gli) in the NILs ranked them as Glu-A3b > Glu-A3c/Glu-A3a > Glu-A3e, and the unextractable polymeric protein content (UPP%), gluten index (GI), and farinograph quality in the NILs ranked them as Glu-A3b > Glu-A3c > Glu-A3a/Glu-A3e. Compared to Glu-A3b and Glu-A3a, the NILs carrying alleles Glu-A3c and Glu-A3e had better cooking and texture properties in CFN. All these findings suggest that the introduction of alleles Glu-A3c or Glu-A3e is an efficient method for quality improvement in CFN, which provides an excellent subunit selection for improving CFN quality.

Association of High and Low Molecular Weight Glutenin Subunits with Gluten Strength in Tetraploid Durum Wheat (Triticum turgidum spp. Durum L.)

The gluten strength and the composition of high- and low-molecular-weight glutenin subunits (HMWGSs and LMWGSs) of fifty-one durum wheat genotypes were evaluated using sodium dodecyl sulfate (SDS) sedimentation testing and SDS polyacrylamide gel electrophoresis (SDS-PAGE). This study examined the allelic variability and the composition of HMWGSs and LMWGSs in T. durum wheat genotypes. SDS-PAGE was proven to be a successful method for identifying HMWGS and LMWGS alleles and their importance in determining the dough quality. The evaluated durum wheat genotypes with HMWGS alleles 7+8, 7+9, 13+16, and 17+18 were highly correlated with improved dough strength. The genotypes containing the LMW-2 allele displayed stronger gluten than those with the LMW-1 allele. The comparative in silico analysis indicated that Glu-A1, Glu-B1, and Glu-B3 possessed a typical primary structure. The study also revealed that the lower content of glutamine, proline, glycine, and tyrosineand the higher content of serine and valine in the Glu-A1 and Glu-B1 glutenin subunits, and the higher cysteine residues in Glu-B1 and lower arginine, isoleucine, and leucine in the Glu-B3 glutenin, are associated with the suitability of durum wheat for pasta making and the suitability of bread wheat with good bread-making quality. The phylogeny analysis reported that both Glu-B1 and Glu-B3 had a closer evolutionary relationship in bread and durum wheat, while the Glu-A1 was highly distinct. The results of the current research may help breeders to manage the quality of durum wheat genotypes by exploiting the allelic variation in glutenin. Computational analysis showed the presence of higher proportions of glutamine, glycine, proline, serine, and tyrosine than the other residues in both HMWGSs and LMWGSs. Thus, durum wheat genotype selection according to the presence of a few protein components effectively distinguishes the strongest from the weakest types of gluten.

Prediction of wheat gluten composition via near-infrared spectroscopy

Gluten composition is an important quality parameter for wheat flour, because it is strongly correlated to baking quality. Wheat proteins are commonly extracted stepwise and analysed using RP-HPLC-UV to determine the gluten composition. This procedure is very time-consuming and labour-intensive. Therefore, a new, fast and easy method to quantitate gluten proteins was established using NIR spectroscopy (NIRS). PLS-regression models were calculated containing 207 samples for calibration and 169 for test set validation. Albumin/globulin (ALGL), gluten, gliadin and glutenin content was predicted with a root mean square error of prediction (RMSEP) of 2.01 mg/g, 6.09 mg/g, 4.25 mg/g and 3.50 mg/g, respectively. High-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS) were predicted with a RMSEP of 1.12 mg/g and 2.38 mg/g. The relative error was too high for ALGL, LMW-GS and HMW-GS, but that of gluten, gliadins and glutenins was in a range comparable to the reference method. Therefore, the new NIRS method can be used to estimate the gluten composition of wheat flour, including the gliadin/glutenin and the LMW-GS/HMW-GS ratio.

The role of feruloylation of wheat bran arabinoxylan in regulating the heat-evoked polymerization behavior of gluten

To further reveal the role of feruloylation of arabinoxylan (AX) in regulating the heat-evoked polymerization behavior of gluten, AX was extracted from wheat bran and in situ modified with lime to obtain AX with controlled ferulic acid (FA) content. The effects of AX with varied FA level on the heat-evoked polymerization of gluten were comparatively studied. The results suggested that AX postponed the disulfide bond mediated polymerization behavior of glutenins and enhanced polymerization degree of glutenin-glutenin and glutenin-gliadin crosslinks upon thermal treatment, while FA moiety suppressed the facilitated polymerization behavior compared with AX free of FA. iTARQ analysis demonstrated that FA moiety of AX mainly suppressed the polymerization of low molecular weight glutenin subunits and α/γ-gliadins in glutenin-gliadin crosslinks. The complete polymerization of glutenin and gliadin elevated the intermolecular β-sheet and ordered α-helix structures at the expense of other structures, while AX stabilized the transformation of secondary structures and was irrelevant with FA level. FA moiety of AX contributed to stabilizing the microenvironment of tryptophan, and evoked the disulfide bond conformation with reduced gauche-gauche-gauche conformation upon formation of glutenin-gliadin crosslinks. AX with the highest FA level exhibited the optimum elevation effect on the viscoelasticity of gluten, which might be attributed to the moderate polymerization of glutenin-gliadin and potential covalent linkage formed between the FA moiety of AX and gluten. This study could contribute to depicting the interacting mechanism of AX and gluten proteins, and further provide basis for exploiting nutritious high-fiber wheat-based products with superior organoleptic quality. • Arabinoxylan (AX) was in situ modified to control the ferulic acid (FA) content. • FA of AX contributed to suppressing the heat-evoked polymerization of gluten proteins. • Suppressed polymerized subunits of gluten upon heating by FA were identified. • FA moiety of AX contributed to stabilizing the microenvironment of tryptophan. • AX with high FA level exhibit optimum elevation effect on viscoelasticity of gluten.

Secondary structure, thermal and functional characterization of low molecular weight glutenin subunits in relation to instant noodle quality

AbstractThe research work aimed to investigate the secondary structure, thermal and functional behavior of gluten, glutenin and low molecular weight‐glutenin subunits (LMW‐GS) of Indian wheat and to establish significant correlation among these techno‐functional attributes. The secondary structure as revealed by Fourier transform infrared (FTIR) spectroscopy indicated that glutenins exhibited maximum absorption intensity (595.6 cm2), followed by LMW‐GS (517.1 cm2) and gluten (276.87 cm2) in the amide I region. The thermogravimetric analysis (TGA) of gluten, glutenin and LMW‐GS recorded disruption of the covalent peptide linkages in the amino acid residues at 273, 275 and 238°C, respectively. The denaturation peak temperature of gluten, glutenin and LMW‐GS, as evident from differential scanning calorimetry (DSC) curves was 112.94, 173.88 and 108.08°C, respectively. Considerable variations were observed in the oil uptake, cooked weight, cooking loss, hardness and chewiness values of instant noodles on addition of gluten, glutenin and LMW‐GS, respectively.Novelty impact statementThe research work provides an insight to the secondary structure and thermal behavior of gluten, glutenin and unreduced LMW‐GS. The functional assessment of these fractions was carried out in terms of instant noodle quality. The cooked instant noodles fortified with these fractions exhibited significant variation in their microstructures as revealed from scanning electron microscopy.

Recent developments on the contribution of glutenin and puroindoline proteins to improve wheat grain quality

AbstractBackground and ObjectivesWheat is most staple food crop for making different end products. The major factors determining the wheat flour end‐use are glutenins and puroindolines. It is very important to identify the composition, variation, and functional characteristics of these key factors.FindingsThe glutenin subunits comprise two subgroups—high molecular weight glutenin subunits (HMW‐GS), and low molecular weight glutenin subunits (LMW‐GS). Puroindolines genes depict a wide diversity of both PINA and PINB allelic forms. The prevalence and relative proportions of these types may vary depending on several genetic and environmental factors.ConclusionCurrent review summarizes recently published research on the impact of glutenin genes governing gluten strength and puroindolines genes related to grain softness. It encompasses recent reports on the development of DNA‐based molecular markers utilized to identify novel alleles associated with HMW‐GS, LMW‐GS, and puroindoline genes in diverse wheat genotypes.Significance and NoveltySubstantial advancements have been made to identify associations between gene expression and grain quality and to develop improved wheat grain quality lines. Nevertheless, a novel marker system such as multiplex polymerase chain reaction and high throughput analysis is needed to screen large numbers of markers at low cost for rapid and precise analysis of germplasm, mapping, and marker‐assisted selection.

Introgression of gluten protein genes associated with the D-genome of bread wheat into durum wheat

In the past thirty years many attempts have been addressed to the possibility to improve the breadmaking characteristics of durum wheat. Since the low breadmaking quality of durum wheat was mainly attributed to the absence of suitable high (HMW-GS) – and low (LMW-GS) molecular weight glutenin subunits, different approaches have been used to introgress D-genome associated LMW-GS HMW-GS, present at the linked Gli-D1/Glu-D3 and Glu-D1 loci. In this paper two sets of durum wheat lines with different introgressions of the D-related glutenin proteins transferred on the short and long arm of chromosome 1A of the recipient variety Svevo, have been characterised. The first set included two lines possessing either the Chinese Spring- (CS) or the Cheyenne- (CNN) type of major alleles at the Gli-D1/Glu-D3 loci, transferred on the short arm of Svevo chromosome 1A. The second group included four lines obtained from crosses between the two lines with the CNN- or CS-type of 1DS alleles with previously obtained durum wheat lines carrying translocations involving the HMW-GS loci Glu-D1a (2 + 12) or Glu-D1d (5 + 10). Quality traits and rheological data were determined for the six translocation lines grown in two different years and compared with the durum variety Svevo. The two translocation lines carrying the two different variants (CS- or CNN-type) at the Gli-D1/Glu-D3 loci behaved differently, the former showing increase of quality characteristics and rheological parameter compared to Svevo, the latter being substantially similar to Svevo. On the contrary, all four double recombinant lines showed maximum values of gluten index and major effects on alveographic parameters due to the presence of the Glu-D1 HMW-GS.

Variations in the quality parameters and gluten proteins in synthetic hexaploid wheats solely expressing the Glu-D1 locus

This study evaluated the quality potential of seven synthetic hexaploid wheats (2n=6x=42, AABBDD) expressing only allelic variation at Glu-D1 of Aegilops tauschii (SHWSD). Major quality parameters related to dough strength, gluten proteins (including high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS), gliadins), and their ratios between SHWSD and the weak gluten wheat control Chuannong 16 (CN16) were measured in at least three environments (except STD7). The zeleny sedimentation value (ZSV), dough development time (DDT), dough stability time (DST), and farinograph quality number (FQN) of SHWSD were considered stable under different environments, with their respective ranges being 8.00–17.67 mL, 0.57–1.50 min, 0.73–1.80 min, and 9.50–27.00. The ZSV, DDT, DST, and FQN of SHWSD were smaller than those of CN16, suggesting that SHWSD had a weaker dough strength than CN16. Although SHWSD had a lower gluten index than CN16, its wet and dry gluten contents were similar to or even higher than those of CN16 in all environments tested. The protein content of grains (12.81–18.21%) and flours (14.20–20.31%) in SHWSD was higher than that in CN16. The amount of HMW-GS in SHWSD sharply decreased under the expression of fewer HMW-GS genes, and the LMW-GS, gliadins, and total glutenins were simultaneously increased in SHWSD in comparison with CN16. Moreover, SHWSD had higher ratios of LMW-GS/glutenin and gliadin/glutenin but a lower ratio of HMW-GS/glutenin than CN16. These results provide necessary information for the utilization of SHWSD in weak-gluten wheat breeding.

Influence of high-molecular-weight glutenin subunit deletions at the Glu-A1 and Glu-D1 loci on protein body development, protein components and dough properties of wheat (Triticum aestivum L.)

High-molecular-weight glutenin subunits (HMW-GSs) play a critical role in determining the viscoelastic properties of wheat. As the organelle where proteins are stored, the development of protein bodies (PBs) reflects the status of protein synthesis and also affects grain quality to a great extent. In this study, with special materials of four near-isogenic lines in a Yangmai 18 background we created, the effects of Glu-A1 and Glu-D1 loci deletions on the development and morphological properties of the protein body, protein components and dough properties were investigated. The results showed that the deletion of the HMW-GS subunit delayed the development process of the PBs, and slowed the increases of volume and area of PBs from 10 days after anthesis (DAA) onwards. In contrast, the areas of PBs at 25 DAA, the middle or late stage of endosperm development, showed no distinguishable differences among the four lines. Compared to the wild type and single null type in Glu-A1, the ratios of HMW-GSs to low-molecular-weight glutenin subunits (LMW-GSs), glutenin macropolymer (GMP) content, mixograph parameters as well as extension parameters decreased in the single null type in Glu-D1 and double null type in Glu-A1 and Glu-D1, while the ratios of gliadins (Gli)/glutenins (Glu) in those types increased. The absence of Glu-D1 subunits decreased both dough strength and extensibility significantly compared to the Glu-A1 deletion type. These results provide a detailed description of the effect of HMW-GS deletion on PBs, protein traits and dough properties, and contribute to the utilization of Glu-D1 deletion germplasm in weak gluten wheat improvement for use in cookies, cakes and southern steamed bread in China and liquor processing.

Characterization of Glutenin Genes in Bread Wheat by Third-Generation RNA Sequencing and the Development of a Glu-1Dx5 Marker Specific for the Extra Cysteine Residue.

High-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS) in a mature grain play important roles in the formation of a glutenin macropolymer and gluten quality. To characterize the expressed glutenin genes of the bread wheat variety Xinmai 26 during seed development, a total of 18 full-length transcripts were obtained by the newly emerged third-generation RNA sequencing of the PacBio Sequel II platform, including 5 transcripts of HMW-GS genes and 13 transcripts of LMW-GS genes (8 intact genes and 5 pseudogenes). Combined with the patterns of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), allelic types of the obtained glutenin genes were, respectively, determined, wherein molecular characterization deduced by transcript1528 (1Dx5) and transcript907 (Glu-A3c) indicated their great influence on dough quality. In addition, a specific functional marker dCAPS5 was developed for the single-nucleotide substitution at position 353 of the 1Dx5 subunit, which was further intensively compared with the other proposed markers to efficiently utilize the 1Dx5 subunit with the extra cysteine residue. This study provides an efficient method to accurately identify and utilize glutenin genes in bread wheat, which is helpful in understanding the contributions of glutenin genes to wheat quality.