Low Molecular Weight Glutenin Research Articles

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.

Arbuscular mycorrhizal fungi impact on yield attributes, protein quantity and quality in bread wheat (Triticum aestivum L.) grown under drought stress

Drought is increasingly becoming a production constraint in wheat world-wide. Arbuscular mycorrhizal fungi (AMF)-bread wheat symbiosis has been shown to improve the tolerance under drought stress. The objective of this study was to determine the effects of AMF inoculation on yield attributes (spike number per plant, spike weight per plant, number of grains per spike, grain weight per spike and 1000 grain weight) and protein quantity and quality in two bread wheat cultivars (PAN3497 and SST806) grown under drought stress. Plant growth was significantly reduced due to drought stress in both cultivars. Shoot dry weight was significantly increased (23%) due to AMF inoculation in SST806. AMF inoculation caused a further significant increase of protein content in both cultivars (10.70% and 13.42% in PAN3497 and SST806, respectively). Low molecular weight (LMW) glutenin was significantly decreased in PAN3497 under drought stress. However, the monomeric proteins were significantly increased by drought and/or a combination of drought and AMF inoculation in both cultivars. In cultivar SST806, significant reduction of polymeric protein was observed due to application of both AMF (6%) and a combination of AMF with drought stress (4%). Regarding the two-dimensional separation of the gluten proteins, drought had the largest effect on protein spots, with AMF causing up-regulation of only some spots. SST806 was generally more drought tolerant than PAN3497.

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.

Unveiling the binding mechanism between starch granule-surface proteins and glutenins during dough mixing process

Starch granule-surface proteins (SGSPs) and gluten proteins can interact to influence dough quality. Despite their pronounced effects, the interaction mechanism remains insufficiently understood. Herein, the binding mechanism between SGSPs and different molecular weight glutenin was explored by experimental methods and single-molecule techniques. Our findings revealed that SGSPs promoted strong binding with both high and low molecular weight glutenin (HMW-GS and LMW-GS). When the ratio of SGSPs and LMW-GS increased to 2:1, the content of disulfide bond increased from 0.03 μmol/L to 0.21 μmol/L while the free sulfhydryl showed the opposite pattern, indicating a tightly packed composite protein structure. A combination of unbiased and steered molecular dynamics simulations further revealed that SGSPs exhibited a higher binding affinity towards LMW-GS in comparison to HMW-GS due to the contributions of solvation and specific interaction energies. This endows the SGSPs-LMW-GS complex with significantly enhanced stability at free state and much higher unbinding force upon stretching, substantially improving the mechanical quality of dough. These findings indicate that SGSPs predominantly affects the interactions between starch and gluten, which will shed light on the dough formation and its properties.

Identification of proteins that contribute to flour strength among elite breeding lines in a breeding program

Gluten, which is a protein aggregate specific to wheat, is crucial in determining the physical properties of wheat flour dough. The gluten is primarily composed of glutenin and gliadin, which are multigenic and comprise diverse proteoforms. Consequently, it is difficult to analyze the quality of gluten by genetic analysis alone. Here, comprehensive protein analysis of wheat cultivars/strains was performed using two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) that allows proteoforms to be resolved by spot position. AlveoConsistograph deformation energy (Fb value) was used as a metric for the strength of the dough. Major proteins resolved by 2D-DIGE were identified by LC/MS/MS. We verified that the Glu-B1al allele significantly influences the physical properties of the dough. Next, excluding the influence of the Glu-B1al allele, we identified proteins that contribute to the physical properties of the dough.Two γ-gliadins and five low molecular weight glutenins were identified. A positive correlation was observed between the spot volume ratio of γ-gliadin and its corresponding Fb value. Thus, γ-gliadin exists as multiple proteoforms, one of which may contribute to the physical properties of dough. Combining the proteins identified in this study will help breeders develop high quality flour.

Gluten subfractions of wheat storage proteins are affected by high night temperature during grain formation

AbstractGluten (gliadin + glutenin) protein in wheat flour is affected by high temperature (day and/or night) resulting in undesirable consequences on dough quality. A study was conducted with early and late‐maturing wheat genotypes, to assess the spatial (superior‐ central and inferior‐ apical and basal spikelets) variation in the composition of gluten subfractions in the developing ear under high night temperature (HNT). We hypothesised that protein content in the superior and inferior grains may show a differential quantitative and qualitative response to HNT. HNT resulted in a significant increase in protein content which exhibited a strong (r = −0.44*) negative correlation with sedimentation volume (SV) that determines baking quality. The late‐maturity genotypes were more responsive to HNT with changes in ω‐5 and γ gliadin subfractions of both superior and inferior spikelets, though a consistent trend was not established. The proportion of high molecular weight (HMW) glutenins increased, whereas low molecular weight (LMW) glutenins reduced in most of the genotypes under HNT. Both HMW and LMW glutenins revealed significant positive (r = 0.43* and r = 0.81***, respectively) correlation with SV. The expression analysis of genes for gluten subfractions showed a significant decrease in transcript abundance of α, ω‐5, γ, HMW, and LMW fractions under HNT.

Wheat DOF transcription factors TaSAD and WPBF regulate glutenin gene expression in cooperation with SPA.

Grain storage proteins (GSPs) quantity and composition determine the end-use value of wheat flour. GSPs consists of low-molecular-weight glutenins (LMW-GS), high-molecular-weight glutenins (HMW-GS) and gliadins. GSP gene expression is controlled by a complex network of DNA-protein and protein-protein interactions, which coordinate the tissue-specific protein expression during grain development. The regulatory network has been most extensively studied in barley, particularly the two transcription factors (TFs) of the DNA binding with One Finger (DOF) family, barley Prolamin-box Binding Factor (BPBF) and Scutellum and Aleurone-expressed DOF (SAD). They activate hordein synthesis by binding to the Prolamin box, a motif in the hordein promoter. The BPBF ortholog previously identified in wheat, WPBF, has a transcriptional activity in expression of some GSP genes. Here, the wheat ortholog of SAD, named TaSAD, was identified. The binding of TaSAD to GSP gene promoter sequences in vitro and its transcriptional activity in vivo were investigated. In electrophoretic mobility shift assays, recombinant TaSAD and WPBF proteins bound to cis-motifs like those located on HMW-GS and LMW-GS gene promoters known to bind DOF TFs. We showed by transient expression assays in wheat endosperms that TaSAD and WPBF activate GSP gene expression. Moreover, co-bombardment of Storage Protein Activator (SPA) with WPBF or TaSAD had an additive effect on the expression of GSP genes, possibly through conserved cooperative protein-protein interactions.

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.

A Narrative Mini Review on Current Status of Hypoallergenic Wheat Development for IgE-Mediated Wheat Allergy, Wheat-Dependent Exercise-Induced Anaphylaxis

Immunoglobulin E (IgE)-mediated food allergies to wheat that develop after school age typically shows a type of wheat-dependent exercise-induced anaphylaxis (WDEIA). At present, avoidance of wheat products or postprandial rest after ingesting wheat is recommended for patients with WDEIA, depending on the severity of the allergy symptoms. ω5-Gliadin has been identified as the major allergen in WDEIA. In addition, α/β-, γ-, and ω1,2-gliadins, high and low molecular weight-glutenins, and a few water-soluble wheat proteins have been identified as IgE-binding allergens in a small proportion of patients with IgE-mediated wheat allergies. A variety of approaches have been manufactured to develop hypoallergenic wheat products that can be consumed by patients with IgE-mediated wheat allergies. In order to analyze such approaches, and to contribute to the further improvement, this study outlined the current status of these hypoallergenic wheat productions, including wheat lines with a reduced allergenicity that are mostly constructed for the patients sensitized to ω5-gliadin, hypoallergenic wheat by enzymic degradation/ion exchanger deamidation, and hypoallergenic wheat by thioredoxin treatment. The wheat products obtained by these approaches significantly reduced the reactivity of Serum IgE in wheat-allergic patients. However, either these were not effective on some populations of the patients, or low-level IgE-reactivity to some allergens of the products was observed in the patients. These results highlight some of the difficulties faced in creating hypoallergenic wheat products or hypoallergenic wheat lines through either traditional breeding or biotechnology approaches in developing hypoallergenic wheat completely safe for all the patients allergic to wheat.

Transcriptome and Proteome Analysis Revealed the Influence of High-Molecular-Weight Glutenin Subunits (HMW-GSs) Deficiency on Expression of Storage Substances and the Potential Regulatory Mechanism of HMW-GSs.

The processing quality of wheat is affected by seed storage substances, such as protein and starch. High-molecular-weight glutenin subunits (HMW-GSs) are the major components of wheat seed storage proteins (SSPs); they are also key determinators of wheat end-use quality. However, the effects of HMW-GSs absence on the expression of other storage substances and the regulation mechanism of HMW-GSs are still limited. Previously, a wheat transgenic line LH-11 with complete deletions of HMW-GSs was obtained through introducing an exogenous gene Glu-1Ebx to the wild-type cultivar Bobwhite by transgenic approach. In this study, comparative seed transcriptomics and proteomics of transgenic and non-transgenic lines at different seed developmental stages were carried out to explore the changes in genes and proteins and the underlying regulatory mechanism. Results revealed that a number of genes, including genes related to SSPs, carbohydrates metabolism, amino acids metabolism, transcription, translation, and protein process were differentially enriched. Seed storage proteins displayed differential expression patterns between the transgenic and non-transgenic line, a major rise in the expression levels of gliadins were observed at 21 and 28 days post anthesis (DPA) in the transgenic line. Changes in expressions of low-molecular-weight glutenins (LMW-GSs), avenin-like proteins (ALPs), lipid transfer proteins (LTPs), and protease inhibitors (PIs) were also observed. In addition, genes related to carbohydrate metabolism were differentially expressed, which probably leads to a difference in starch component and deposition. A list of gene categories participating in the accumulation of SSPs was proposed according to the transcriptome and proteome data. Six genes from the MYB and eight genes from the NAC transcription families are likely important regulators of HMW-GSs accumulation. This study will provide data support for understanding the regulatory network of wheat storage substances. The screened candidate genes can lay a foundation for further research on the regulation mechanism of HMW-GSs.

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

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

Effects of Cysteine and Inorganic Sulfur Applications at Different Growth Stages on Grain Protein and End-Use Quality in Wheat.

The aim of this study was to test the significant effects of inorganic sulfur and cysteine on grain protein and flour quality in wheat and to provide a theoretical basis of wheat cultivation techniques with high yield and quality. In the field experiment, a winter wheat cultivar, Yangmai 16, was used, and five treatments were established, i.e., S0 (no sulfur fertilizer application during the whole wheat growth period), S(B)60 (60 kg ha−1 inorganic sulfur fertilizer was applied as the basal fertilizer), Cys(B)60 (60 kg ha−1 cysteine sulfur fertilizer was applied as the basal fertilizer), S(J)60 (60 kg ha−1 inorganic sulfur fertilizer was applied as the jointing fertilizer), and Cys(J)60 (60 kg ha−1 cysteine sulfur fertilizer was applied as the jointing fertilizer). The fertilizer application at jointing stage showed a better influence than basal fertilizer application on protein quality; for the content of albumin, gliadin, and high molecular weight glutenin (HMW-GS), Cys(J)60 was the best among these treatments. An increase of 7.9%, 24.4%, 43.5%, 22.7% and 36.4% was found in grain yield, glutenin content, glutenin macro-polymer (GMP), low molecular weight glutenin (LMW-GS), and S content under Cys(J)60, in relation to the control, respectively. A similar trend was found in the end-use quality, as exemplified by an increase of 38.6%, 10.9%, 60.5%, and 109.8% in wet gluten content, dry gluten content, sedimentation volume, and bread-specific volume, respectively; a decrease of 69.3% and 69.1% in bread hardness and bread chewiness was found under Cys(J)60. In terms of application period, topdressing at jointing stage is compared with base fertilizer, the sulfur fertilizer application at jointing stage showed larger effects on grain protein and flour quality, from the different types of sulfur fertilizer, the application of cysteine performed better than the use of inorganic sulfur. The Cys(J)60 exhibited the best effects on protein and flour quality. It was suggested that sufficient sulfur application at jointing stage has the potential to enhance the grain protein and flour quality.

Purification and immunoglobulin E epitopes identification of low molecular weight glutenin: an allergen in Chinese wheat

As one of the most important cereals, wheat (Triticum aestivum) has high nutritional value and is widely cultivated in China. However, wheat can cause severe allergic reactions, and a growing number of people are developing allergies to Chinese wheat. Low molecular weight glutenin (LMW-GS), an important allergen in susceptible populations, is responsible for celiac disease and wheat contacts dermatitis. In this study, LMW-GS was highly purified from Chinese wheat (Xiaoyan 6) and further identified and characterized. In addition, 8 peptides were predicted efficiently by 5 immunological tools, among which five peptides showed significant immunoglobulin E (IgE) binding abilities. Two specific epitopes were found to be in the non-conserved region of the amino acid sequence of LMW-GS, which was speculated to be the specific epitope of Chinese wheat. This systematic research of LMW-GS may provide new insights into the prevention of wheat allergy and development of hypoallergenic wheat products.

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.

Drought and heat stress effects on gluten protein composition and its relation to bread-making quality in wheat

Wheat grain proteins are largely affected by environmental conditions, with drought and heat stress causing considerable changes to gluten composition, resulting in variations in bread-making quality. Size-exclusion high-performance liquid chromatography (SE-HPLC) was used to assess the effects of moderate and severe drought and heat stress on variation in gluten proteins in bread wheat cultivars. Extractable gliadin (exGLi), mixing time (MixT) and total polymeric proteins (TPP) were largely genetically determined, while flour protein content (FPC) and extractable albumins/globulins (exAG) were significantly affected by treatment. The two levels of both heat and drought stress caused differential expression of gluten proteins. The unextractable polymeric proteins were reduced under severe heat stress, while both extractable and unextractable low molecular weight glutenin fractions were increased, leading to a weakening of the dough and deterioration of quality. Severe drought caused increased values of all bread-making related characteristics and loaf volume (LV), coupled with significant increases in unextractable polymeric and monomeric proteins and exGLi. Moderate heat stress caused increases in extractable HMW glutenin, which negatively affected bread-making characteristics. The large and total polymeric proteins were consistently correlated with LV for all treatments, although extractable HMW glutenins were generally negatively correlated with baking characteristics under all treatments.

Climate change effects on bread wheat phenology and grain quality: A case study in the north of Italy.

Increasing temperatures, heat waves, and reduction of annual precipitation are all the expressions of climate change (CC), strongly affecting bread wheat (Triticum aestivum L.) grain yield in Southern Europe. Being temperature the major driving force of plants’ phenological development, these variations also have effects on wheat phenology, with possible consequences on grain quality, and gluten protein accumulation. Here, through a case study in the Bolognese Plain (North of Italy), we assessed the effects of CC in the area, the impacts on bread wheat phenological development, and the consequences on grain gluten quality. The increasing trend in mean annual air temperature in the area since 1952 was significant, with a breakpoint identified in 1989, rising from 12.7 to 14.1°C, accompanied by the signals of increasing aridity, i.e., increase in water table depth. Bread wheat phenological development was compared in two 15-year periods before and after the breakpoint, i.e., 1952–1966 (past period), and 2006–2020 (present period), the latest characterized by aridity and increased temperatures. A significant shortening of the chronological time necessary to reach the main phenological phases was observed for the present period compared to the past period, finally shortening the whole life cycle. This reduction, as well as the higher temperature regime, affected gluten accumulation during the grain-filling process, as emerged analyzing gluten composition in grain samples of the same variety harvested in the area both before and after the breakpoint in temperature. In particular, the proportion of gluten polymers (i.e., gliadins, high and low molecular weight glutenins, and their ratio) showed a strong and significant correlation with cumulative growing degree days (CGDDs) accumulated during the grain filling. Higher CGDD values during the period, typical of CC in Southern Europe, accounting for higher temperature and faster grain filling, correlated with gliadins, high molecular weight glutenins, and their proportion with low molecular weight glutenins. In summary, herein reported, data might contribute to assessing the effects of CC on wheat phenology and quality, representing a tool for both predictive purposes and decision supporting systems for farmers, as well as can guide future breeding choices for varietal innovation.

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.

Marker-assisted introgression of genes into rye translocation leads to the improvement in bread making quality of wheat (Triticum aestivum L.).

Introgression of genes from related species can be a powerful way to genetically improve crop yields, but selection for one trait can come at the cost to others. Wheat varieties with translocation of the short arm of chromosome 1 from the B genome of wheat (1BS) with the short arm of chromosome 1 from rye (1RS) are popular globally for their positive effect on yield and stress resistance. Unfortunately, this translocation (1BL.1RS) is also associated with poor bread making quality, mainly due to the presence of Sec-1 on its proximal end, encoding secalin proteins, and the absence of Glu-B3/Gli-B1-linked loci on its distal end, encoding low molecular weight glutenin subunits (LMW-GS). The present study aims to replace these two important loci on the 1RS arm with the wheat 1BS loci, in two popular Indian wheat varieties, PBW550 and DBW17, to improve their bread-making quality. Two donor lines in the cultivar Pavon background with absence of the Sec-1 locus and presence of the Glu-B3/Gli-B1 locus, respectively, were crossed and backcrossed with these two selected wheat varieties. In the advancing generations, marker assisted foreground selection was done for Sec-1- and Glu-B3/Gli-B1+ loci while recurrent parent recovery was done with the help of SSR markers. BC2F5 and BC2F6 near isosgenic lines (NILs) with absence of Sec-1 and presence of Glu-B3/Gli-B1 loci were evaluated for two years in replicated yield trials. As a result of this selection, thirty promising lines were generated that demonstrated improved bread making quality but also balanced with improved yield-related traits compared to the parental strains. The study demonstrates the benefits of using marker-assisted selection to replace a few loci with negative effects within larger alien translocations for crop improvement.

Effects and underlying mechanisms of insoluble dietary fiber and ferulic acid on the crumb structure of steamed bread

This study investigated the effects and underlying mechanisms of insoluble dietary fiber (IDF) and ferulic acid (FA) on the crumb structure of steamed bread. Both IDF and FA had significant (p < 0.05) adverse effects on the crumb structure of steamed bread, except for small doses of FA (0.3 g), while the simultaneous addition of IDF and FA exacerbated the adverse effects. IDF reduced the bound water and free water content of the dough and increased the immobilized water content due to physical filling and strong water absorption, which hindered the formation of gluten. Moreover, IDF mainly reduced the extractability of low molecular weight glutenin subunit (LMW-GS), thereby promoting glutenin polymerization, which further limited the extensibility and fermentation of the dough. The fermentation height and CO2 production of the dough with FA added decreased rapidly to 0 mm and 4 mL, and then remained stable. This was attributed to the fact that FA resulted in a denser gluten network structure. The extractability of glutenin indicated that FA reduced the extractabilities of glutenin subunits and increased the extractabilities of gliadin subunits. The extractability of LMW-GS with 1.8 g of FA was reduced by 25.03% compared with the control sample, which far exceeded the 6.39% reduction of high molecular weight glutenin subunit. This revealed that FA was mainly through cross-linking with LMW-GS to promote gluten polymerization. Moreover, the addition of IDF + FA exacerbated the gluten polymerization through the formation of macromolecular polymers, which further affected the crumb structure of steamed bread.