Agropyron elongatum HMW-glutenins have a potential to improve wheat end-product quality through targeted chromosome introgression

Novel Genetic Loci from Triticum timopheevii Associated with Gluten Content Revealed by GWAS in Wheat Breeding Lines

The content and quality of gluten in wheat grain is a distinctive characteristic that determines the final properties of wheat flour. In this study, a genome-wide association study (GWAS) was performed on a wheat panel consisting of bread wheat varieties and the introgression lines (ILs) obtained via hybridization with tetraploid wheat relatives. A total of 17 stable quantitative trait nucleotides (QTNs) located on chromosomes 1D, 2A, 2B, 3D, 5A, 6A, 7B, and 7D that explained up to 21% of the phenotypic variation were identified. Among them, the QTLs on chromosomes 2A and 7B were found to contain three and six linked SNP markers, respectively. Comparative analysis of wheat genotypes according to the composition of haplotypes for the three closely linked SNPs of chromosome 2A indicated that haplotype TT/AA/GG was characteristic of ten ILs containing introgressions from T. timopheevii. The gluten content in the plants with TT/AA/GG haplotype was significantly higher than in the varieties with haplotype GG/GG/AA. Having compared the newly obtained data with the previously reported quantitative trait loci (QTLs) we inferred that the locus on chromosome 2A inherited from T. timopheevii is potentially novel. The introgression lines containing the new locus can be used as sources of genetic factors to improve the quality traits of bread wheat.

Molecular Characterization and Marker Development of the HMW-GS Gene from Thinopyrum elongatum for Improving Wheat Quality

The quality of wheat primarily depends on its storage protein quality, especially in regards to gluten content and high-molecular-weight glutenin subunits (HMW-GS). The number of HMW-GS alleles is limited in bread wheat (Triticum aestivum L.), whereas it is abundant in wheat relatives. Therefore, HMW-GS alleles from wheat relatives could provide a potential for improving quality in wheat breeding. Thinopyrum elongatum (EE) is one of the relatives of wheat. The E genome is closely related to the ABD genome in wheat; therefore, Th. elongatum is often used as an excellent exogenous gene donor for wheat genetic improvement. In this study, the high-molecular glutenin subunit gene was cloned and sequenced from Th. elongatum. A specific molecular marker for identifying the Glu-1Ey subunit gene was developed and applied to detected wheat-Th. elongatum alien introgression lines. Quality analysis indicated that the substitution and addition lines containing Th. elongatum alleles significantly (p < 0.05) increased grain protein content by 3.76% to 5.11%, wet-gluten content by 6.55% to 8.73%, flour 8-MW by 0.25% to 6.35%, and bread volume value by 33.77 mL to 246.50 mL, in comparing it with Chinese Spring. The GMP content and lactic acid SRC showed significant positive correlations with flour processing quality and might be used as indicators for wheat quality. The results were expected to provide a novel route for improving processing quality in wheat quality breeding.

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-1E^bx 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.

Establishment and identification of six wheat-Thinopyrum ponticum disomic addition lines derived from partial amphiploid Xiaoyan 7430

Six wheat-Thinopyrum ponticum disomic addition lines derived from partial amphiploid Xiaoyan 7430 were identified using in situ hybridization and SNP microarray, the homoeologous group and stripe rust resistance of each alien chromosome were determined, and Th. ponticum chromosome-specific markers were developed. Xiaoyan 7430 is a significant partial amphiploid, which is used to set up a bridge for transferring valuable genes from Thinopyrum ponticum (Podp.) Barkworth & D.R. Dewey into common wheat. To accelerate the application of these useful genes in enriching the genetic variability of cultivated wheat by chromosome engineering, a complete set of derived addition lines has been created from Xiaoyan 7430. The chromosome composition of each line was characterized by the combination of genomic in situ hybridization and multicolor fluorescence in situ hybridization (mc-FISH), and the homoeology of each alien chromosome was determined by wheat SNP microarray analysis. Addition line WTA55 with alien group-6 chromosome was evaluated resistant to stripe rust isolates at both the seedling and grain-filling stages (Zadoks scale at z.11 and z.73). Diagnostic marker analysis proved that it could carry a novel stripe rust resistance gene derived from Th. ponticum. Furthermore, a FISH probe and 45 molecular markers specific for alien chromosomes were developed based on specific-locus amplified fragment sequencing (SLAF-seq). Of which 27 markers were separately located on single alien chromosome, and some of them could be used to identify the derived translocation lines. This set of addition lines as well as the molecular markers and the FISH probe will promote the introgression of abundant variation from Th. ponticum into wheat in wheat improvement programs.

Influence of Biofortified Colored Wheats (Purple, Blue, Black) on Physicochemical, Antioxidant and Sensory Characteristics of Chapatti (Indian Flatbread)

Biofortified colored wheat (black, blue, and purple) is rich in anthocyanins and phenolic acid compounds that impart positive physiological effects in humans. A large proportion of wheat is consumed in the form of Chapatti in Asian countries. The effect of chapatti cooking on the proximate composition, bioactive compounds (anthocyanins and phenolics), and antioxidant activities of these wheat varieties were checked in this study. Apart from acceptable sensory parameters, good taste, and soft texture of chapatti, biofortified colored wheat chapatti and flour had higher dietary fibers, protein content, and lower carbohydrate content. Higher soluble and insoluble phenolic compounds, anthocyanin content, and antioxidant activity were in the order of black > blue > purple > white. Chapatti making has reduced their antioxidant activity and anthocyanin content in comparison to flour. Moreover, the reduction in antioxidant activity is less as compared to the decrease in anthocyanin content. Our results suggest that colored wheat can be a better alternative to normal wheat for preparing chapatti as it would have additional health-promoting activities.

Effect of wheat grain protein composition on end-use quality

The quality of wheat products has been a new challenge next to wheat production which was achieved substantially during green revolution. The end-use quality of wheat is an essential factor for its commercial demand. The quality of wheat is largely based on the wheat storage proteins which extensively influences the dough properties. High molecular weight glutenin subunits (HMWGS), low molecular weight glutenin subunits (LMWGS) and gliadins significantly influence the end-use quality. Genomics and proteomics study of these gluten proteins of bread and durum wheat have explored new avenues for precise identification of the alleles and their role in end-use quality improvement. Secalin protein of Secale cereale encoded by Sec-1 loci and is associated with 1RS.1BL translocation has been known for deterioration of end-use quality. Chromosomal manipulations using various approaches have led to the development of new recombinant lines of wheat without secalin. Advanced techniques associated with assessment of end-use quality have integrated the knowledge of useful or deteriorating HMWGS/LMWGS alleles and their potential role in end-use quality. This review gives a comprehensive insight of different aspects of the end-use quality perspective for bread making in wheat along with some information on the immunological interference of gluten in celiac disease.

A wheat-Aegilops umbellulata addition line improves wheat agronomic traits and processing quality

Wheat processing quality is mainly correlated with high-molecular-weight glutenin subunits (HMW-GS) of grain endosperm. In bread wheat, the number of HMW-GS alleles are limited. However, wheat relative species possess numerous HMW-GS genes. In our previous study, a pair of novel HMW-GS 1Ux3.5+1Uy1.9 was characterized in Aegilops umbellulata. In this work, a novel wheat-Ae. umbellulata addition line, GN05, carrying a pair of 1U chromosome was developed and identified via cytogenetic analysis. Protein composition analysis indicated that GN05 carried HMW-GS of Ae. umbellulata. Accumulation of glutenin macropolymer (GMP) showed that GN05 had a much higher GMP content than the recurrent parent Chinese Spring. Rheological characteristics were analyzed by mixing test and the dough quality of GN05 was significantly improved compared to Chinese Spring. The results presented here may provide a valuable resource for the improvement of bread wheat quality.

Identification of COS markers specific for Thinopyrum elongatum chromosomes preliminary revealed high level of macrosyntenic relationship between the wheat and Th. elongatum genomes

Thinopyrum elongatum (Host) D.R. Dewey has served as an important gene source for wheat breeding improvement for many years. The exact characterization of its chromosomes is important for the detailed analysis of prebreeding materials produced with this species. The major aim of this study was to identify and characterize new molecular markers to be used for the rapid analysis of E genome chromatin in wheat background. Sixty of the 169 conserved orthologous set (COS) markers tested on diverse wheat-Th. elongatum disomic/ditelosomic addition lines were assigned to various Th. elongatum chromosomes and will be used for marker-assisted selection. The macrosyntenic relationship between the wheat and Th. elongatum genomes was investigated using EST sequences. Several rearrangements were revealed in homoeologous chromosome groups 2, 5, 6 and 7, while chromosomes 1 and 4 were conserved. Molecular cytogenetic and marker analysis showed the presence of rearranged chromosome involved in 6ES and 2EL arms in the 6E disomic addition line. The selected chromosome arm-specific COS markers will make it possible to identify gene introgressions in breeding programmes and will also be useful in the development of new chromosome-specific markers, evolutionary analysis and gene mapping.

Anthocyanin bio-fortified colored wheat: Nutritional and functional characterization

Colored wheat, rich in anthocyanins, has created interest among the breeders and baking industry. This study was aimed at understanding the nutritional and product making potential of our advanced, high yielding and regionally adapted colored wheat lines. Our results indicated that our advanced colored wheat lines exhibited higher anthocyanin content and antioxidant activity than donor wheat lines and it varied in the order of white<purple<blue<black wheat. UPLC chromatogram revealed that anthocyanin composition and peak pattern is not only dependent on donor genotype but also background of recipient genotype. Interestingly, the purple wheat extract showed highest anti-inflammatory effect and followed the trend of white<blue<black<purple. Nutritional (carbohydrates, sugar, protein, ash, dietary fibre and vitamins) and processing parameters in relation to end-use quality (SDS sedimentation, gluten content, alveograph) of advanced colored lines were similar to high yielding white wheat cultivar. Colored wheat lines showed high iron and zinc content compared to white wheat indicating double bio-fortification. Therefore, our advanced colored wheat lines with high anthocyanin, iron and zinc contents showed antioxidant and anti-inflammatory activity and possessed desirable features for product making and commercial utilization.

Interspecific and intergeneric hybridization as a source of variation for wheat grain quality improvement

The hybridization events with wild relatives and old varieties are an alternative source for enlarging the wheat quality variability. This review describes these process and their effects on the technological and nutritional quality. Wheat quality and its end-uses are mainly based on variation in three traits: grain hardness, gluten quality and starch. In recent times, the importance of nutritional quality and health-related aspects has increased the range of these traits with the inclusion of other grain components such as vitamins, fibre and micronutrients. One option to enlarge the genetic variability in wheat for all these components has been the use of wild relatives, together with underutilised or neglected wheat varieties or species. In the current review, we summarise the role of each grain component in relation to grain quality, their variation in modern wheat and the alternative sources in which wheat breeders have found novel variation.

Molecular Cytogenetic Characterization of New Wheat-Dasypyrum breviaristatum Introgression Lines for Improving Grain Quality of Wheat

As an important relative of wheat (Triticum aestivum L), Dasypyrum breviaristatum contains novel high molecular weight glutenin subunits (HMW-GSs) encoded by Glu-1Vb genes. We identified new wheat-D. breviaristatum chromosome introgression lines including chromosomes 1V^b and 1V^bL.5V^bL by fluorescence in situ hybridization (FISH) combined with molecular markers. We found that chromosome changes occurred in the wheat-D. breviaristatum introgression lines and particularly induced the deletion of 5BS terminal repeats and formation of a new type of 5B-7B reciprocal translocation. The results imply that the D. breviaristatum chromosome 1V^b may contain genes which induce chromosomal recombination in wheat background. Ten putative high molecular weight glutenin subunit (HMW-GS) genes from D. breviaristatum and wheat-D. breviaristatum introgression lines were isolated. The lengths of the HMW-GS genes in Dasypyrum were significantly shorter than typical HMW-GS of common wheat. A new y-type HMW-GS gene, named Glu-Vb1y, was characterized in wheat-D. breviaristatum 1V^b introgression lines. The new wheat-D. breviaristatum germplasm displayed reduced plant height, increased tillers and superior grain protein and gluten contents, improved gluten performance index. The results showed considerable potential for utilization of D. breviaristatum chromosome 1V^b segments in future wheat improvement.

A novel compensating wheat-Thinopyrum elongatum Robertsonian translocation line with a positive effect on flour quality

Wheat flours are used to produce bread, pasta, breakfast cereals, and biscuits; the various properties of these end-products are attributed to the gluten content, produced as seed storage proteins in the wheat endosperm. Thus, genes encoding gluten protein are major targets of wheat breeders aiming to improve the various properties of wheat flour. Here, we describe a novel compensating wheat-Thinopyrum elongatum Robertsonian translocation (T1AS.1EL) line involving the short arm of wheat chromosome 1A (1AS) and the long arm of Th. elongatum chromosome 1E (1EL); we developed this line through centric breakage-fusion. Compared to the common wheat cultivars Chinese Spring and Norin 61, we detected two additional 1EL-derived high-molecular-weight glutenin subunits (HMW-GSs) in the T1AS.1EL plants. Based on the results of an SDS-sedimentation volume to estimate the gluten strength of T1AS.1EL-derived flour, we predict that T1AS.1EL-derived flour is better suited to bread-making than Chinese Spring- and Norin 61-derived flour and that this is because of its greater gluten diversity. Also, we were able to assign 33 of 121 wheat PCR-based Landmark Unique Gene markers to chromosome 1E of Th. elongatum. These markers can now be used for further chromosome engineering of the Th. elongatum segment of T1AS.1EL.

Rapid Development and Characterization of Chromosome Specific Translocation Line of Thinopyrum elongatum with Improved Dough Strength

The protein content and its type are principal factors affecting wheat (Triticum aestivum) end product quality. Among the wheat proteins, glutenin proteins, especially, high molecular weight glutenin subunits (HMW-GS) are major determinants of processing quality. Wheat and its primary gene pool have limited variation in terms of HMW-GS alleles. Wild relatives of wheat are an important source of genetic variation. For improvement of wheat processing quality its wild relative Thinopyrum elongatum with significant potential was utilized. An attempt was made to replace Th. elongatum chromosome long arm (1EL) carrying HMW-GS genes related to high dough strength with chromosome 1AL of wheat with least or negative effect on dough strength while retaining the chromosomes 1DL and 1BL with a positive effect on bread making quality. To create chromosome specific translocation line [1EL(1AS)], double monosomic of chromosomes 1E and 1A were created and further crossed with different cultivars and homoeologous pairing suppressor mutant line PhI . The primary selection was based upon glutenin and gliadin protein profiles, followed by sequential genomic in situ hybridization (GISH) and fluorescent in situ hybridization (FISH). These steps significantly reduced time, efforts, and economic cost in the generation of translocation line. In order to assess the effect of translocation on wheat quality, background recovery was carried out by backcrossing with recurrent parent for several generations and then selfing while selecting in each generation. Good recovery of parent background indicated the development of almost near isogenic line (NIL). Morphologically also translocation line was similar to recipient cultivar N61 that was further confirmed by seed storage protein profiles, RP-HPLC and scanning electron microscopy. The processing quality characteristics of translocation line (BC4F6) indicated significant improvement in the gluten performance index (GPI), dough mixing properties, dough strength, and extensibility. Our work aims to address the challenge of limited genetic diversity especially at chromosome 1A HMW-GS locus. We report successful development of chromosome 1A specific translocation line of Th. elongatum in wheat with improved dough strength.

Chromosomal constitutions of five wheat - Elytrigia elongata partial amphiploids as revealed by GISH, multicolor GISH and FISH

A combination of meiotic pairing analysis and in situ hybridization (genomic in situ hybridization [GISH], multicolor GISH [mcGISH] and fluorescence in situ hybridization [FISH]) of five Triticum aestivum (Linnaeus, 1753) - Elytrigia elongata (Podpěra, 1902) (2n = 10x = 70) amphiploids was employed to investigate the genomic constitution and relationships between wheat and alien chromosomes. GISH, multicolor GISH and FISH patterns of mitotic chromosomes indicate that the genomic constitution of the five partial amphiploids (XY693, XY7430, SN19, SN20 and SN122) are 14A + 12B + 14D + 8Js + 8J, 12A + 16B + 14D + 2St + 8Js + 2J + 2 W-E, 14A + 14B + 14D + 4St + 8Js, 14A + 14B + 14D + 2St + 10Js + 2J, and 14A + 14B + 14D + 2St + 8Js + 4J, respectively. Analysis of meiotic chromosome pairing in the F₁ hybrids between these five partial amphiploids suggests that SN20 and SN122 are the most closely related amphiploids and are somewhat related with XY693 and XY7430. However, the alien chromosome constitutions of SN19 differed from the other four amphiploids. In addition, a new pairing between wheat and E. elongata chromosomes was distinguished in some cells of the hybrids SN19 × XY7430, SN20 × XY7430 and SN122 × XY7430.

New molecular markers and cytogenetic probes enable chromosome identification of wheat-Thinopyrum intermedium introgression lines for improving protein and gluten contents

New molecular markers were developed for targeting Thinopyrum intermedium 1St#2 chromosome, and novel FISH probe representing the terminal repeats was produced for identification of Thinopyrum chromosomes. Thinopyrum intermedium has been used as a valuable resource for improving the disease resistance and yield potential of wheat. A wheat-Th. intermedium ssp. trichophorum chromosome 1St#2 substitution and translocation has displayed superior grain protein and wet gluten content. With the aim to develop a number of chromosome 1St#2 specific molecular and cytogenetic markers, a high throughput, low-cost specific-locus amplified fragment sequencing (SLAF-seq) technology was used to compare the sequences between a wheat-Thinopyrum 1St#2 (1D) substitution and the related species Pseudoroegneria spicata (St genome, 2n = 14). A total of 5142 polymorphic fragments were analyzed and 359 different SLAF markers for 1St#2 were predicted. Thirty-seven specific molecular markers were validated by PCR from 50 randomly selected SLAFs. Meanwhile, the distribution of transposable elements (TEs) at the family level between wheat and St genomes was compared using the SLAFs. A new oligo-nucleotide probe named Oligo-pSt122 from high SLAF reads was produced for fluorescence in situ hybridization (FISH), and was observed to hybridize to the terminal region of 1St#L and also onto the terminal heterochromatic region of Th. intermedium genomes. The genome-wide markers and repetitive based probe Oligo-pSt122 will be valuable for identifying Thinopyrum chromosome segments in wheat backgrounds.

Molecular and Cytological Comparisons of Chromosomes 7el₁, 7el₂, 7E(e), and 7E ⁱ Derived from Thinopyrum

Thinopyrum chromosomes 7el1, 7el2, 7E(e), and 7E(i), homoeologous to group 7 chromosomes of common wheat (Triticum aestivum), were determined to have many useful agronomical traits for wheat improvement. To analyze the genetic relationships among the 4 Thinopyrum 7E chromosomes, the conserved orthologous set markers, genomic in situ hybridization (GISH), and meiotic chromosome pairing were used in this study. The unweighted pair-group method with arithmetical averages (UPGMA) analysis indicated that 7el1, derived from T. ponticum, and 7E(i), derived from T. intermedium, were the most closely related. 7el2, derived from T. ponticum, was relatively distant from the 7el1-7E(i) complex. While 7E(e), derived from T. elongatum, was more distantly related to 7el1, 7el2, and 7E(i). This is the first report showing that 7el1 and 7E(i) may be similar, which could be explained by the similar chromosome signal distribution revealed by GISH as well as UPGMA analysis revealed by both molecular markers and the highest frequency of meiotic pairing. The newly developed genome-specific molecular markers may be useful for marker-assisted selection of Lr19, Bdv3, and Fhblop.

Introduction of chromosome segment carrying the seed storage protein genes from chromosome 1V of Dasypyrum villosum showed positive effect on bread-making quality of common wheat

Development of wheat- D. villosum 1V#4 translocation lines; physically mapping the Glu - V1 and Gli - V1 / Glu - V3 loci; and assess the effects of the introduced Glu - V1 and Gli - V1 / Glu - V3 on wheat bread-making quality. Glu-V1 and Gli-V1/Glu-V3 loci, located in the chromosome 1V of Dasypyrum villosum, were proved to have positive effects on grain quality. However, there are very few reports about the transfer of the D. villosum-derived seed storage protein genes into wheat background by chromosome manipulation. In the present study, a total of six CS-1V#4 introgression lines with different alien-fragment sizes were developed through ionizing radiation of the mature female gametes of CS--D. villosum 1V#4 disomic addition line and confirmed by cytogenetic analysis. Genomic in situ hybridization (GISH), chromosome C-banding, twelve 1V#4-specific EST-STS markers and seed storage protein analysis enabled the cytological physical mapping of Glu-V1 and Gli-V1/Glu-V3 loci to the region of FL 0.50-1.00 of 1V#4S of D. villosum. The Glu-V1 allele of D. villosum was Glu-V1a and its coded protein was V71 subunit. Quality analysis indicated that Glu-V1a together with Gli-V1/Glu-V3 loci showed a positive effect on protein content, Zeleny sedimentation value and the rheological characteristics of wheat flour dough. In addition, the positive effect could be maintained when specific Glu-V1 and Gli-V1/Glu-V3 loci were transferred to the wheat genetic background as in the case of T1V#4S-6BS · 6BL, T1V#4S · 1BL and T1V#4S · 1DS translocation lines. These results showed that the chromosome segment carrying the Glu-V1 and Gli-V1/Glu-V3 loci in 1V#4S of D. villosum had positive effect on bread-making quality, and the T1V#4S-6BS · 6BL and T1V#4S · 1BL translocation lines could be useful germplasms for bread wheat improvement. The developed 1V#4S-specific molecular markers could be used to rapidly identify and trace the alien chromatin of 1V#4S in wheat background.

The development of 7E chromosome-specific molecular markers for Thinopyrum elongatum based on SLAF-seq technology

Thinopyrum elongatum is an important relative of wheat, it is favored by many researchers for the disease resistant genes that exist in its E genome. Some studies have showed that the 7E chromosome of Th. elongatum contains resistance genes related to Fusarium head blight and wheat rust. Therefore, developing 7E chromosome-specific molecular markers linked to resistance genes will provide an important tool for exploring and using the resistant genes of Th. elongatum. In addition, it would greatly contribute in the effort to cultivate disease-resistant wheat varieties. Featured in high throughput, high-accuracy and low-cost, SLAF-seq technology has been widely used in molecular breeding, system evolution, and germplasm resource detection. Based on SLAF-seq, 518 specific fragments on the 7E chromosome of Th. elongatum were successfully amplified. A total of 135 primers were designed according to 135 randomly selected fragments, and 89 specific molecular markers of Th. elongatum were developed, with efficiencies up to 65.9%. These markers were all detected in a variety of materials, and they are all proved to be specific and stable. These markers can be used not only for detecting the 7E chromosome of Th. elongatum but also for providing an important theoretical and practical basis for wheat breeding by marker-assisted selection (MAS). This paper reports the first application of SLAF-seq technology with a high success rate in developing specific molecular markers for Th. elongatum, providing a strong case for the application of this new technology.

Comparative proteome analysis of glutenin synthesis and accumulation in developing grains between superior and poor quality bread wheat cultivars

BACKGROUND

Wheat glutenins are the major determinants of wheat quality. In this study, grains at the development stage from three wheat cultivars (Jimai 20, Jin 411 and Zhoumai 16) with different bread-making quality were harvested based on thermal times from 150 °C(d) to 750 °C(d) , and were used to investigate glutenin accumulation patterns and their relationships with wheat quality.

RESULTS

High and low molecular weight glutenin subunits (HMW-GSs and LMW-GSs) were synthesised concurrently. No obvious correlations between HMW/LMW glutenin ratios and dough property were observed. Accumulation levels of HMW-GSs and LMW-GSs as well as 1Bx13 + 1By16 and 1Dx4 + 1Dy12 subunits were higher in superior gluten quality cultivar Jimain 20 than in poor quality cultivar Jing 411 and Zhoumai 16. According to the results of two-dimensional gel electrophoresis, six types of accumulation patterns in LMW-GSs were identified and classified. The possible relationships between individual LMW-GSs and gluten quality were established.

CONCLUSION

The high accumulation level of HMW-GSs and LMW-GSs as well as 1Bx13 + 1By16 and 1Dx4 + 1Dy12 subunits contributed to the superior gluten quality of Jimai 20. Two highly expressed and 16 specifically expressed LMW glutenin subunits in Jimain 20 had positive effects on dough quality, while 17 specifically expressed subunits in Zhoumai 16 and Jing 411 appeared to have negative effects on gluten quality.