Glu-D1 Locus Research Articles

Dough properties and baking quality of near isogenic lines with single HMW-GS null at Glu-A1, Glu-B1 and Glu-D1 loci in soft wheat

High molecular weight glutenin subunits (HMW-GSs) encoded by the Glu-1 loci are key factors in determining wheat processing quality. However, the contributions of single HMW-GS to dough viscoelastic properties and end-use quality have not been well understood, especially in soft wheat. In this study, the kernel samples of five Near Isogenic Lines (NILs) of a soft wheat each with individual HMW-GS null were investigated. Significant lower SDS-sedimentation volume and lactic acid solvent retention capacity (SRC) were observed in the NILs, compared to the wild type (WT). Except for the NIL with Glu-D1y12 null, the other NILs were associated with significantly lower dough mixing tolerance compared to the WT. Also, the deletion of individual HMW-GS was associated with reduction in dough elasticity and strength, compared to the WT, with the exception of the Glu-A1x1 null. Moreover, Glu-B1x7 was the most important HMW-GS in determining dough mixing tolerance and elasticity. Compared to the WT, the deletions of Glu-D1x2, Glu-B1x7 and Glu-B1y8 significantly increased alveograph L, and decreased alveograph P and P/L ratios. All NILs with single HMW-GS null showed better sugar snap cookie baking quality than the WT. New germplasm and tools are identified for improving dough viscoelasticity and baking quality in soft wheat.

Selection of marker systems for determining the allelic composition of high molecular glutenin loci in winter wheat

Aim. Selection of marker systems and conducting multiplex polymerase chain reactions to determine the allelic composition of the Glu-A1, Glu-B1 and Glu-D1 loci, which determine the high quality of flour in common wheat samples. Methods. Polymerase chain reaction (PCR) using specific primers for the Glu-A1, Glu-B1 and Glu-D1 loci of wheat. Results. PCR analysis was performed to detect the insertion at 43 b. p. in the MAR region, in varieties with the Glu-B1al allele, the presence of an amplicon 563 b. p. long was observed, for varieties that carry other alleles of the locus – an amplicon 520 b. p. long. The results on the Glu-D1 locus showed that for № 2, № 3, № 4, № 7, № 8, № 10, № 11, № 19, № 20, № 21 subunits (5 + 10) were identified. Conclusions. With the help of allele-specific primers, the allelic composition of loci of high molecular weight glutenins was determined in 22 lines wheat. Three alleles Glu-A1a, Glu-A1b, Glu-A1c were found in the Glu-A1 locus; in the Glu-B1 locus, only the Glu-B1al allele was detected, there are two alleles at the Glu-D1 locus: Glu-D1a and Glu-D1d (the Glu-D1a allele predominated). As a result of our research, samples of soft wheat (lines № 2, № 7, № 21) were selected, which can be attributed to genotypes with high baking quality of the flour.

GLUTENIN DIVERSITY OF FLOUR WHEAT (Triticum aestivum L.) FOR COOKIE QUALITY IN MEXICO

Glutenins are high- and low-molecular-weight proteins (HMW-G and LMW-G). They play a determining role in genetic improvement to define industrial quality in flour wheat, so understanding their variability is necessary for directing selection toward a specific quality. The objective of this research was to determine the diversity of HMW-G and LMW-G alleles of genotypes from the flour wheat breeding program of the National Institute of Forestry, Agricultural, and Livestock Research (INIFAP) useful for cookie quality. Twenty-five genotypes were used, including six Mexican cookie varieties, as well as 21 genotypes introduced from an international collection of accessions from the International Maize and Wheat Improvement Center (CIMMYT). HMW-G and LMW-G were identified based on their separation on polyacrylamide gels in the presence of sodium dodecyl sulfate. For HMW-G, the 2* variant in Glu-A1 was the most frequent variant for the trial and introduction nursery, with more than 80 %. At the Glu-B1 locus, the 7+9 and 7 variants were the most frequent, with 60 and 38.1 % in trial and nursery, respectively. For Glu-D1, the 2+12 variant was the most frequent in the trial with 64 %, and 5+10 with 85.7 % in nursery. The latter allele favors baking quality. For the Glu-A1 and Glu-D1 loci, it is necessary to introduce genotypes with null alleles or with the 2+121 variant in Glu-D1 associated with cookie quality. For the highest-frequency variants of LMW-G, c in Glu-A3, h in Glu-B3, and b in Glu-D3 are associated with baking quality. With the aforementioned, it is concluded that there is a low frequency and little variation in useful alleles of HMW-G and LMW-G for cookie quality in the introduced accessions analyzed, implying that new genetic sources that favor it should be explored.

ASSESSMENT OF HIGH MOLECULAR WEIGHT PROTEINS IN SELECTED INDIGENOUS BREAD WHEAT VARIETIES OF PAKISTAN

Higher molecular weight gluten subunits (HMW-GS) articulate variation in allelic frequency, reflecting a strong correlation with bread quality. In order to determine this quality trait, 23 different Pakistani indigenous wheat varieties were screened that may be used as selection criteria in a breeding program. For detecting variations in HMW-GS, sodium dodecyl sulfate acrylamide gel electrophoresis was used. In all, 77 Glu-1 were identified including 25 at Glu-A1, 26 at Glu-B1 and 26 at Glu-D1. Alleles at Glu-1 were 2* with a frequency of 53.3% and N with 60% frequency at Glu-A1, 6+8 with 60%, 17+18 with 45 % at Glu-B1 and 5+10 with 60% and 72% at Glu-D1. The highest frequency of subunits 20 and 5+10 were found at Glu-B1-e and Glu-D1 (a), followed by a frequency of 2* and Null at Glu-A1 (b, c), which is then followed by 2+12 at GluD-1 (a). The lowest frequency of 13+16, 17+18 and 6+8 were observed at Glu-B1 (f, i, d), respectively. Glu-A1, Glu-B1, and Glu-D1 alleles showed genetic index (i.e. 0.587, 0.54), (0.587. 0.065 and 0.48, 0.39, respectively) with an average of 0.55 and 0.37. The glu-D1 locus has a lower genetic index comparatively. The composition N, 20, 5+10 was found in maximum number (4) in Fakhr-e-Sarhad, Pasban, Pirsabak-2004 and Tatara genotypes, followed by the composition of 2*, 20, 2+12 in one check (Marvi-2000) and two varieties i.e. Chakwal-97 and Bakhtawar-92. The results describing the allelic frequency and composition of bread wheat would benefit further breeding plans for wheat to select good quality parameters.

HMW-GSs 1Dx3+1Dy12 contribute to a suitable wheat gluten strength that confers superior Chinese steamed bread quality.

The aim of this study was to clarify the effects of the high-molecular-weight glutenin subunits (HMW-GSs) 1Dx3+1Dy12 (3+12) and 1Dx4+1Dy12 (4+12) at the Glu-D1 locus on gluten and Chinese steamed bread (CSB) quality. The grain protein content and composition, gluten content and gluten index, farinograph properties, and CSB quality were investigated using four wheat near-isogenic lines (NILs) carrying HMW-GSs 1Dx2+1Dy12 (2+12), 3+12, 4+12 and 1Dx5+1Dy10 (5+10), respectively. The unextractable polymeric protein (UPP) and glutenin macropolymer (GMP) content, gluten index, dough development time, stability time, and farinograph quality number of four NILs all ranked as 5+10>3+12>2+12/4+12, such as the gluten index ranked as 5+10(44.88%)>3+12(40.07%)>2+12(37.46%)/4+12(35.85%); however, their contributions to the quality of CSB were ranked as 3+12>5+10>2+12/4+12, such as the specific volume ranked as 3+12(2.64mL/g)>5+10(2.49mL/g)>2+12(2.36mL/g)/4+12(2.35mL/g), which indicated that a suitable gluten strength (3+12) was crucial to making high-quality CSB. In addition, subunits 4+12 had a similar quality performance to low-quality subunits 2+12. All these findings suggested that, except for the acknowledged high-quality subunits 5+10, the introduction of 3+12 at the Glu-D1 locus is an efficient way for quality improvement of gluten as well as CSB.

Effects of high-molecular-weight glutenin subunit on hard-steamed bread quality.

Steamed bread (SB) is a daily food in many countries in the world, but the relationship between HMW-GS and the quality of SB remain unclear. This study investigated the effects of 12 subunit combinations on the characteristics of SB, including volume, physical properties, and sensory evaluation, combined with the microstructure and dough rheological properties. The locus effect results showed, volume and physical properties of SB were Glu-D1>Glu-B1>Glu-A1, while sensory scores Glu-B1>Glu-D1>Glu-A1. According to individual subunit effects, subunit 1 at Glu-A1 locus, 7+8 and 7+9 subunits at Glu-B1 locus, and 2+10 and 5+12 subunits at Glu-D1 locus were significantly superior to other subunits in physical indices like volume, chewiness, glueyness, and sensory scores, and were less affected by moisture. The effect of subunits combination is mainly affected by subunits, and the combination of superior subunits tends to make SB quality better. The subunit combinations (1, 7+8, 5+12), (N, 7+9, 2+10) and (1, 7+9, 5+12) had better physical properties indexes, sensory scores, dense, uniform and delicate micro-pore structure, and smaller thickness wall. The results showed that protein content, wet gluten content and stability time were the main factors affecting the volume and physical properties of SB. The protein content, wet gluten content and stability time of flour in 7+8, 7+9, 2+10 and 5+12 subunits were higher. Therefore, the quality of SB containing these subunits was found better.

Baking Quality of Organically Grown European Winter Wheat Germplasm in the South-East of Romania

Baking quality of organic winter wheat remains a significant challenge, primarily due to the usually lower grain protein concentration realized in organic agriculture. This study examined eighty-four winter wheat genotypes from Europe under organic conditions in the south-east of Romania, during two contrasting seasons. Various quality traits, i.e., grain protein content, bread volume, dough strength, breakdown and extensibility were analyzed. All examined traits exhibited significant differences among cultivars. Molecular assays, utilizing markers for Glu-A1, Glu-D1, Glu-B3g and NAM-A1 loci revealed genetic diversity within the germplasm. The study highlighted sixteen genotypes with bread volume statistically significant different from the average trial. In the organic system the Glu-A1x2* allele had positive effects on bread volume, water absorption, dough strength and extensibility. At Glu-D1, the alleles for Dx5 + Dy10 were detected in over 85% cultivars and showed positive effects on dough development time and extensibility. Another locus with positive effect on baking quality was NAM-A1. In this study the haplotype NAM-A1c had the highest frequency (51%), followed by NAM-A1d (38%) and NAM-A1a (11%). Both NAM-A1a and NAM-A1c haplotypes positively affected bread volume, water absorption, dough strength and extensibility. The Glu-B3g allele had a positive effect on development time. However, these genes could not explain the whole variation of quality parameters, as some of the best cultivars had unfavorable alleles while other cultivars carrying positive alleles had low quality. Obviously, other factors strongly influenced the quality parameters in organic agriculture, and further research is needed to understand their nature. Our results suggest the potential for achieving improved breadmaking quality, under organic conditions, by exploring genetic possibilities. However, combining suitable breadmaking quality with high yield will remain a challenge.

Assessing Payne score accuracy through a bread wheat multi-genotype and multi-environment set from CIMMYT

The Payne score is a prevalent strategy for assessing wheat quality by considering the distinct contributions of specific high-molecular-weight glutenin subunits. Despite its extensive use, the limited germplasm used in its development (84 British cultivars from the early 1980s) may limit its accuracy when is applied to other type of germplasm. Here we tested the Payne score accuracy and related scales using an extensive dataset. The precision of the scale is higher for Glu-A1 and Glu-D1 loci, particularly when predicting dough strength, and loaf volume. However, for dough extensibility, the accuracy decreased. For Glu-B1 it could discriminate differences to some extent, but higher scores did not always correspond to higher quality values, and vice versa. When the total Payne score was evaluated, the most pronounced degree of differentiation between scale values was observed for gluten strength related traits. When analyzing the total Payne score for various haplotypes, higher values for gluten strength, and loaf volume generally corresponded to higher Payne scores; however, some samples with low values were ranked with the highest scores and vice versa. Our findings suggest that there is a probability of selecting cultivars with high Payne scores that do not match the desired quality.

Analysis of genetic diversity and population structure using glutenin protein markers in various wheat varieties

AbstractThe study of polymorphism of glutenin makes it possible to identify and isolate desirable genotypes with higher grain quality. In the last few years, only a part of the genetic diversity among the modern and popular wheat germplasm and varieties based on the polymorphism of glutenin subunits are captured. To address this 107 wheat varieties released across different agricultural zones in India, were used to investigate HMW-GS and LMW-GS allele polymorphism, gene diversity and genetic variation in the Glu-1 and Glu-3 loci. Among the different HMW-GS, the highest genetic variation was observed at the Glu-D1 locus with both Glu-D1a and Glu-D1d possessing genetic variation of 0.490, 0.484 respectively. The highest genetic variation at the Glu-A3 locus was observed at the Glu-A3c and GluA3b possessing a genetic variation of 0.463, 0.411 respectively. This was followed by the Glu-B3j having a genetic variation of 0.386 at the Glu-B3 locus. Over 20 years a remarkable increase in the Glu-D1d allele is observed in the newly released varieties in India. Among all the zones, Glu-A1-null is the least frequent allele at the Glu-1 locus, however, it is present as the predominant allele in the NHZ of India. This study elucidates the relationships of these HMW and LMW allelic frequencies and genetic variation with their geographical distribution over the two different periods. This study provides reference data that can be used to assist the breeding, quality evaluation and development of good-quality wheat varieties.

Identification and Introgression of a Novel HMW-GS Gene from Aegilops tauschii

High molecular weight glutenin subunits (HMW-GSs) play a major role in determining the dough quality of wheat. As the D genome donor of hexaploid wheat, Aegilops tauschii is an important genetic resource for wheat quality breeding. In the present study, a novel HMW-GSs from Ae. tauschii was identified and designated as Glu-Dt1. Multiple sequence alignment indicated that one cysteine was mutated into arginine in the y-type subunit. Site-directed mutagenesis technology was applied to verify the function of gene Glu-Dt1. Three introgression lines (ILs), B9, B25, and B35 with the Glu-D1 loci substituted by Glu-Dt1 were detected from the BC3F5 population derived from hexaploid wheat cultivar Jimai22 and Ae. tauschii Y215 through the direct hybridization approach. The dough quality and agronomic performance analysis were performed, which provide valuable resources for wheat genetic studies and breeding for distinctive end-use quality.

Identification of Glu-D1 Alleles and Novel Marker-Trait Associations for Flour Quality and Grain Yield Traits under Heat-Stress Environments in Wheat Lines Derived from Diverse Accessions of Aegilops tauschii.

Heat stress during grain filling is considered one of the major abiotic factors influencing wheat grain yield and quality in arid and semi-arid regions. We studied the effect of heat stress on flour quality and grain yield at moderate and continuous heat stress under natural field conditions using 147 lines of wheat multiple synthetic derivatives (MSD) containing Aegilops tauschii introgressions. The study aimed to identify the marker–trait associations (MTAs) for the quality traits and grain yield under heat-stress conditions and identify stress-resilient germplasm-combining traits for good flour quality and grain yield. The MSD lines showed considerable genetic variation for quality traits and grain yield under heat-stress conditions; some lines performed better than the recurrent parent, Norin 61. We identified two MSD lines that consistently maintained relative performance (RP) values above 100% for grain yield and dough strength. We found the presence of three high-molecular-weight glutenin subunits (HMW-GSs) at the Glu-D1 locus derived from Ae. tauschii, which were associated with stable dough strength across the four environments used in this study. These HMW-GSs could be potentially useful in applications for future improvements of end-use quality traits targeting wheat under severe heat stress. A total of 19,155 high-quality SNP markers were used for the genome-wide association analysis and 251 MTAs were identified, most of them on the D genome, confirming the power of the MSD panel as a platform for mining and exploring the genes of Ae. tauschii. We identified the MTAs for dough strength under heat stress, which simultaneously control grain yield and relative performance for dough strength under heat-stress/optimum conditions. This study proved that Ae. tauschii is an inexhaustible resource for genetic mining, and the identified lines and pleiotropic MTAs reported in this study are considered a good resource for the development of resilient wheat cultivars that combine both good flour quality and grain yield under stress conditions using marker-assisted selection.

Effects of glutenins (Glu-1 and Glu-3) allelic variation on dough properties and bread-making quality of CIMMYT bread wheat breeding lines

Wheat dough characteristics and end-use quality are strongly influenced by the amount and specific composition of the glutenins, the major components of gluten. Such proteins are divided into high-molecular-weight glutenins, encoded by the Glu-A1 , Glu-B1 and Glu-D1 loci; and low-molecular-weight glutenins, encoded by the Glu-A3 , Glu-B3 and Glu-D3 loci. Allelic variation at each of these loci has been associated with changes in wheat functionality. However, most of the studies conducted so far included a relatively limited number of genotypes. Also for this reason, it is still unclear which locus contributes more to dough characteristics and how important are the interactions between the glutenin loci. To try to answer these questions, the quality data of 4623 grain samples derived from 2550 genotypes and generated across 10 years at the CIMMYT bread wheat breeding program, was used to estimate the effect of the glutenin loci and their interactions on gluten quality and bread-making potential. Gluten strength was the trait more strongly influenced by glutenin variations, with the Glu-B1 , Glu-D1 and Glu-B3 loci having the greatest effect. Among the glutenin alleles, Glu-A1a , Glu-A1b , Glu-B1al , Glu-B1i , Glu-B1f , Glu-D1d , Glu-A3b , Glu-A3d , Glu-A3f , Glu-B3c and Glu-B3d were associated in general with greater gluten strength, good extensibility and higher bread loaf volume. Differently, alleles Glu-A1c , Glu-B1a , Glu-B1d , Glu-D1a , Glu-A3e and Glu-B3j were associated with an overall poor quality. Glutenin interactions were significantly associated with most of the analyzed quality traits even if their influence was often lower compared to the effect of the single glutenin loci. This is probably the largest study ever done on the effects of the glutenins on wheat quality. The results obtained confirm the importance of such proteins on wheat quality variation and corroborate the usefulness of determining the glutenin profile to improve the selection efficiency for wheat quality in breeding programs. • Wheat quality and glutenin’s data of 4623 grain samples derived from 2550 genotypes was used. • Gluten strength was the trait more strongly influenced by glutenin variations. • Several alleles were associated to good or bad quality, respectively. • This is probably the largest study ever done about glutenins effects on quality.

The effects of high molecular weight glutenin subunits in wheat flours on soft- and hard-dough biscuit products quality

High molecular weight glutenin subunits (HMW-GS) are the main wheat gluten proteins in flour that determine the viscoelastic properties of various types of dough. In this study, the effects of HMW-GS on various quality characteristics of certain soft wheat biscuit products were investigated. Results of the study showed that subunit 5x + 10y in the Glu-D1 locus increased the gluten strength of a flour and, consequently, negatively affected the physical and sensory properties of the resulting soft-dough biscuit products made with that flour. While product results suggested that the wheat genotypes carrying the allele 1 in Glu-A1 should be selected with care, in terms of biscuit sensory properties, the combination of the null allele in Glu-A1 and subunits 7 in Glu-B1 and 2x + 12y in Glu-D1 can lead to increased success of wheat breeding programs aimed at flours preferred for soft-dough biscuit products. For hard-dough biscuit products, subunit 2* can be used as a marker, in order to eliminate those soft wheat lines having too-high gluten strength. The combinations of HMW-GS 1, 7x + 9y, and 5x + 10y, along with the 1B/1R wheat-rye translocation, were considered to result in flours for production of hard-dough group biscuits. This study suggested that the most suitable HMW-GS combinations of wheat genotypes for soft- and hard-dough biscuit products. Those combinations considering wheat-rye translocation could be used for selection, or elimination, purposes in breeding programs targeting soft wheat varieties for specific baked products.

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.

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.

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.

Increasing the Versatility of Durum Wheat through Modifications of Protein and Starch Composition and Grain Hardness

Although durum wheat (Triticum durum L. ssp. durum Desf.) has traditionally been used to make a range of food products, its use has been restricted due to the absence of the D-genome glutenin proteins, the relatively low variability in starch composition, and its very hard grain texture. This review focuses on the manipulation of the starch and protein composition and modification of the hardness of durum wheat in order to improve its technological and nutritional value and expand its utilization for application to a wider number of end products. Starch is composed of amylopectin and amylose in a 3:1 ratio, and their manipulation has been explored for achieving starch with modified composition. In particular, silencing of the genes involved in amylose and amylopectin synthesis has made it possible to isolate durum wheat lines with amylose content varying from 2–3% up to 75%. This has created opportunities for new products with different properties and enhanced nutritional value. Durum-made bread has generally inferior quality to bread made from common wheat. Attempts to introduce the Glu-D1 subunits 1Dx5 + 1Dy10 and 1Dx2 + 1Dy12 produced stronger dough, but the former produced excessively strong, inelastic doughs, and loaf volume was either inferior or not affected. In contrast, the 1Dx2 + 1Dy12 sometimes improved bread loaf volume (LV) depending on the glutenin subunit background of the genotype receiving these genes. Further breeding and selection are needed to improve the dough extensibility to allow higher LV and better texture. The versatility of durum wheat has been greatly expanded with the creation of soft-textured durum via non-GMO introgression means. This soft durum mills like soft hexaploid wheat and has similar baking properties. The pasta quality is also not diminished by the soft-textured kernels. The Glu-D1 locus containing the subunits 1Dx2 + 1Dy12 has also been introgressed to create higher quality soft durum bread.

Enhancing Wheat Flour Quality Through Introgression of High-Molecular-Weight Glutenin Subunits From Aegilops tauschii Accessions

Narrow genetic diversity in the wheat gene pool restricts the improvement of wheat quality traits. Aegilops tauschii possesses valuable genetic diversity that can be used to improve not only biotic and abiotic stresses in arid regions but also wheat yield and quality. Our study, which used 392 multiple synthetic derivatives (MSD) panel developed with Ae. tauschii Coss. introgressions, had three main aims: to explore the genetic diversity of high-molecular-weight glutenin subunits (HMW-GS), to investigate the dough strength and the relationship between protein content and grain yield, and to identify lines with a good flour quality. A wide range of allelic diversity was observed at the Glu-D1 locus, reflecting the impact of the different introgressed portions of Ae. tauschii, and a wide variation was found in dough strength even between lines having the same composition of HMW-GS. We report a negative impact on dough strength of subunit 5t+10t from Ae. tauschii and a relatively positive impact of subunit 2t+12.1t. We identified four MSD lines with significantly enhanced flour quality. Regressing the grain yield of the MSD lines against protein content showed no correlation between the two traits and identified lines with comparable grain yield to the recurrent parent and higher protein content. The identified MSD lines could provide a valuable genetic resource for enhancing the end-use quality of flour without any loss in productivity.

Establishment and Application of Multiplex PCR Systems Based on Molecular Markers for HMW-GSs in Wheat

High-molecular-weight glutenin subunits (HMW-GSs) encoded by alleles at the Glu-A1, Glu-B1, and Glu-D1 loci confer unique end-use quality properties of common wheat (Triticum aestivum L.). Wheat accessions with the high-quality HMW-GSs combination of Ax2*/Bx7OE/Dx5 usually exhibit strong gluten characteristics. In order to stack these three high-quality subunit genes by molecular markers in strong gluten wheat breeding, an agarose gel-based multiplex PCR marker for these high-quality HMW-GSs and two agarose gel-based multiplex PCR markers detecting the homozygosity of Ax2* and Bx7OE subunits were developed. These markers were verified in an F2 segregating population from a cross between a medium-gluten winter wheat cultivar with the HMW-GSs combination of Ax null/Bx7 + By8/Dx4 + Dy12 and a strong-gluten spring wheat cultivar with the HMW-GSs combination of Ax2*/Bx7OE + By8*/Dx5 + Dy10. By integrating the newly established multiplex PCR markers and a published co-dominant PCR marker of the Dx5 subunit, a complete molecular marker selection system was established. After multiple rounds of molecular marker-assisted selection with the system, 17 homozygous winter wheat lines that stacked the three high-quality HMW-GSs were generated. The gluten strength of these homozygous lines was comparable to their strong-gluten parent, but significantly higher than that of their medium-gluten parent by measuring their lactic acid-sodium dodecyl sulfate solvent retention capacities of whole wheat meal. The multiplex PCR systems established in the present study can be used for molecular marker-assisted selection of strong gluten wheats.

Pyramiding of genes for grain protein content, grain quality, and rust resistance in eleven Indian bread wheat cultivars: a multi-institutional effort.

The online version contains supplementary material available at 10.1007/s11032-022-01277-w.