Explore the vast range of titles available.

Present research focused on polymeric fractions of two wheat varieties’ (DBW88 and HI1500) evaluation for molecular weight and HMW-GS composition using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), degree of crystallinity using X-ray diffraction, microstructural assessment through scanning electron microscopy (SEM), for thermal profiling using differential scanning calorimetry (DSC) and secondary structure analysis employing Fourier transform infrared (FTIR) spectroscopy technique. Glutenin fractions were identified into high molecular weight (HMW) glutenin fractions (140 kDa to 75 kDa) and low molecular weight (LMW) glutenin fractions (45 kDa to 30 kDa) as per SDS-PAGE for both varieties. XRD results displayed amorphous nature of all extracted polymeric protein fractions. SEM results revealed dense stranded structure in gluten matrix due to the addition of polymeric wheat protein and its further subfractions with subtle variation. Thermal stability of glutenins of both varieties DBW88 (161.95 °C with 808.48 J/g) and HI1500 (160.64 °C with 785.57 J/g) were observed to be highest due to highly ordered structure, followed by HMW glutenins, gluten and LMW glutenins in case of DBW88 while LMW glutenins, gluten and HMW glutenins in case of HI1500. Highest proportion of β-sheets and β-turns was observed in HMW glutenins of DBW88 and LMW glutenins of HI1500.

Background Glutenin contents and compositions are crucial factors influencing the end-use quality of wheat. Although the composition of glutenin fractions is well known, there has been relatively little research on the genetic basis of glutenin fractions in wheat. Results To elucidate the genetic basis for the contents of glutenin and its fractions, a population comprising 196 recombinant inbred lines (RILs) was constructed from two parents, Luozhen No.1 and Zhengyumai 9987, which differ regarding their total glutenin and its fraction contents (except for the By fraction). Forty-one additive Quantitative Trait Loci (QTL) were detected in four environments over two years. These QTL explained 1.3% - 53.4% of the phenotypic variation in the examined traits. Forty-three pairs of epistatic QTL (E-QTL) were detected in the RIL population across four environments. The QTL controlling the content of total glutenin and its seven fractions were detected in clusters. Seven clusters enriched with QTL for more than three traits were identified, including a QTL cluster 6AS-3 , which was revealed as a novel genetic locus for glutenin and related traits. Kompetitive Allele-Specific PCR (KASP) markers developed from the main QTL cluster 1DL-2 and the previously developed KASP marker for the QTL cluster 6AS-3 were validated as significantly associated with the target traits in the RIL population and in natural varieties. Conclusions This study identified novel genetic loci related to glutenin and its seven fractions. Additionally, the developed KASP markers may be useful for the marker-assisted selection of varieties with high glutenin fraction content and for identifying individuals in the early developmental stages without the need for phenotyping mature plants. On the basis of the results of this study and the KASP markers described herein, breeders will be able to efficiently select wheat lines with favorable glutenin properties and develop elite lines with high glutenin subunit contents.

Background High-molecular-weight glutenin subunits (HMW-GS) play important roles in the elasticity of dough made from wheat. The HMW-GS null line is useful for studying the contribution of HMW-GS to the end-use quality of wheat. Methods In a previous work, we cloned the Glu-1E b x gene from Thinopyrum bessarabicum and introduced it into the wheat cultivar, Bobwhite. In addition to lines expressing the Glu-1E b x gene, we also obtained a transgenic line (LH-11) with all the HMW-GS genes silenced. The HMW-GS deletion was stably inherited as a dominant and conformed to Mendel’s laws. Expression levels of HMW-GS were determined by RT-PCR and epigenetic changes in methylation patterns and small RNAs were analyzed. Glutenins and gliadins were separated and quantitated by reversed-phase ultra-performance liquid chromatography. Measurement of glutenin macropolymer, and analysis of agronomic traits and end-use quality were also performed. Results DNA methylation and the presence of small double-stranded RNA may be the causes of post-transcriptional gene silencing in LH-11. The accumulation rate and final content of glutenin macropolymer (GMP) in LH-11 were significantly lower than in wild-type (WT) Bobwhite. The total protein content was not significantly affected as the total gliadin content increased in LH-11 compared to WT. Deletion of HMW-GS also changed the content of different gliadin fractions. The ratio of ω-gliadin increased, whereas α/β- and γ-gliadins declined in LH-11. The wet gluten content, sedimentation value, development time and stability time of LH-11 were remarkably lower than that of Bobwhite. Bread cannot be made using the flour of LH-11. Conclusions Post-transcriptional gene silencing through epigenetic changes and RNA inhibition appear to be the causes for the gene expression deficiency in the transgenic line LH-11. The silencing of HMW-GW in LH-11 significantly reduced the dough properties, GMP content, wet gluten content, sedimentation value, development time and stability time of flour made from this wheat cultivar. The HMW-GS null line may provide a potential material for biscuit-making because of its low dough strength.

Main conclusionMeta-analysis in wheat for three major quality traits identified 110 meta-QTL (MQTL) with reduced confidence interval (CI). Five GWAS validated MQTL (viz., 1A.1, 1B.2, 3B.4, 5B.2, and 6B.2), each involving more than 20 initial QTL and reduced CI (95%) (< 2 cM), were selected for quality breeding programmes. Functional characterization including candidate gene mining and expression analysis discovered 44 high confidence candidate genes associated with quality traits.A meta-analysis of quantitative trait loci (QTL) associated with dough rheology properties, nutritional traits, and processing quality traits was conducted in wheat. For this purpose, as many as 2458 QTL were collected from 50 interval mapping studies published during 2013–2020. Of the total QTL, 1126 QTL were projected onto the consensus map saturated with 249,603 markers which led to the identification of 110 meta-QTL (MQTL). These MQTL exhibited an 18.84-fold reduction in the average CI compared to the average CI of the initial QTL (ranging from 14.87 to 95.55 cM with an average of 40.35 cM). Of the 110, 108 MQTL were physically anchored to the wheat reference genome, including 51 MQTL verified with marker-trait associations (MTAs) reported from earlier genome-wide association studies. Candidate gene (CG) mining allowed the identification of 2533 unique gene models from the MQTL regions. In-silico expression analysis discovered 439 differentially expressed gene models with > 2 transcripts per million expressions in grains and related tissues, which also included 44 high-confidence CGs involved in the various cellular and biochemical processes related to quality traits. Nine functionally characterized wheat genes associated with grain protein content, high-molecular-weight glutenin, and starch synthase enzymes were also found to be co-localized with some of the MQTL. Synteny analysis between wheat and rice MQTL regions identified 23 wheat MQTL syntenic to 16 rice MQTL associated with quality traits. Furthermore, 64 wheat orthologues of 30 known rice genes were detected in 44 MQTL regions. Markers flanking the MQTL identified in the present study can be used for marker-assisted breeding and as fixed effects in the genomic selection models for improving the prediction accuracy during quality breeding. Wheat orthologues of rice genes and other CGs available from MQTLs can be promising targets for further functional validation and to better understand the molecular mechanism underlying the quality traits in wheat.

Key messageAn expressed HMW glutenin subunit Glu-Ay showed positive impacts on a range of wheat processing quality and yield traits. The grain protein compositions are significantly optimised for baking, resulting in a better breadmaking quality.The unique breadmaking properties of wheat flour are related to the quality and quantity of high-molecular weight glutenin subunits (HMW-GSs) present in the grain. In the current study, the silent 1Ay HMW-GS allele, present in most bread wheat cultivars, was replaced by the expressed 1Ay21* allele, which was introgressed into Australian bread wheat cultivar Lincoln by a backcrossing and selfing scheme. Stability of gene expression and the effect of the introgressed 1Ay21* subunit on protein composition, agronomic traits, flour functionality, and breadmaking quality were studied using BC4F5 grain grown in glasshouse and field. Field phenotyping and grain quality testing showed that the 1Ay21* gene conferred significant improvements to a range of traits, including an increase in grain protein content by up to 9%, UPP% by up to 24%, bread volume by up to 28%. The glasshouse experiment and one of the field trials showed positive 1Ay21* effects on yield, while one field trial showed one significant effects. This indicates that expression of the 1Ay21* gene has the potential of simultaneously increasing protein content and grain yield under certain environment. The qualitative improvements of the grain also led to a reduction of the energy required during the baking process in addition to the significant positive effects on bread quality.

Background In common wheat ( Triticum aestivum  L.), allelic variations in the high-molecular-weight glutenin subunits Glu - B1  locus have important effects on grain end-use quality. The Glu - B1  locus consists of two tightly linked genes encoding x- and y-type subunits that exhibit highly variable frequencies. However, studies on the discriminating markers of the alleles that have been reported are limited. Here, we developed 11 agarose gel-based PCR markers for detecting Glu - 1Bx and Glu - 1By alleles. Results By integrating the newly developed markers with previously published PCR markers, nine Glu - 1Bx locus alleles ( Glu - 1Bx6 , Glu - 1Bx7 , Glu - 1Bx7 *, Glu - 1Bx7 OE , Glu - 1Bx13 , Glu - 1Bx14 (−) , Glu - 1Bx14 (+) / Bx20 , and Glu - 1Bx17 ) and seven Glu-1By locus alleles ( Glu - 1By8 , Glu - 1By8 *, Glu - 1By9 , Glu - 1By15/By20 , Glu - 1By16 , and Glu - 1By18 ) were distinguished in 25 wheat cultivars. Glu - 1Bx6 , Glu - 1Bx13 , Glu - 1Bx14 (+) / Bx20 , Glu - 1By16 , and Glu - 1By1 8 were distinguished using the newly developed PCR markers. Additionally, the Glu - 1Bx13 and Glu - 1Bx14 (+) / Bx20 were distinguished by insertions and deletions in their promoter regions. The Glu - 1Bx6, Glu - 1Bx7, Glu - 1By9 , Glu - 1Bx14 (−) , and Glu - 1By15 / By20 alleles were distinguished by using insertions and deletions in the gene-coding region. Glu - 1By13 , Glu - 1By16 , and Glu - 1By18 were dominantly identified in the gene-coding region. We also developed a marker to distinguish between the two Glu - 1Bx14 alleles. However, the Glu - 1Bx14 (+)  +  Glu - 1By15 and Glu - 1Bx20  +  Glu - 1By20 allele combinations could not be distinguished using PCR markers. The high-molecular-weight glutenin subunits of wheat varieties were analyzed by ultra-performance liquid chromatography and sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and the findings were compared with the results of PCR analysis. Conclusions Seven Glu - 1Bx and four Glu - 1By allele detection markers were developed to detect nine Glu - 1Bx and seven Glu - 1By locus alleles, respectively. Integrating previously reported markers and 11 newly developed PCR markers improves allelic identification of the Glu - B1 locus and facilitates more effective analysis of Glu - B1 alleles molecular variations, which may improve the end-use quality of wheat.

Background Nitrogen is one basic element of amino acids and grain protein in wheat. In field experiments, wheat plants were subjected to different timing of nitrogen topdressing treatments: at the stages of emergence of the top fifth leaf (TL5), top third leaf (TL3) and top first leaf (TL1) to test the regulatory effects of nitrogen topdressing timing on grain protein quality. The underlying mechanisms were elucidated by clarifying the relationship between proteolysis in vegetative organs and accumulation of amino acids in the endosperm cavity, conversion of amino acids, and storage protein synthesis in endosperm of wheat grain. Results Delayed nitrogen topdressing up-regulated gene expression related to nitrogen metabolism and protease synthesis in the flag leaf, followed by more free amino acids being transported to both the cavity and the endosperm from 7 days after anthesis (DAA) to 13 DAA in TL1. TL1 enhanced the conversion between free amino acids in endosperm and upregulated the expression of genes encoding high molecular weight (HMW) and low molecular weight (LMW) subunits and protein disulfide isomerases-like (PDIL) proteins, indicating that the synthesis and folding of glutenin were enhanched by delayed nitrogen topdressing. As a consequense, the content of glutenin macropolymers (GMP) and glutenin increased with delaying nitrogen topdressing. Conclusions The results highlight the relationship between nitrogen remobilization and final grain protein production and suggest that the nitrogen remobilization processes could be a potential target for improving the quality of wheat grain. Additionally, specific gene expression related to nitrogen topdressing was identified, which conferred more detailed insights into underlying mechanism on the modification protein quality.

ABSTRACT The introduction of reduced height (Rht) genes into wheat during the Green Revolution led to lower plant height, but their effect on protein composition was unknown. Therefore, the protein composition of near isogenic lines (NILs) of four Triticum aestivum genotypes with five different Rht allele/allele combinations was compared to the tall wild‐type (rht) by modified Osborne fractionation. The semi‐dwarfing (Rht1, Rht2) and the dwarf Rht gene combination (Rht1 + 2) only had a small effect on protein composition. The extreme dwarfing genes (Rht3 and Rht2 + 3) decreased glutenin content leading to higher gliadin‐to‐glutenin ratios compared to the tall wild‐type (rht). A strong environmental influence on the protein composition was observed. The introduction of the semi‐dwarfing and dwarfing Rht genes (Rht1, Rht2, Rht1 + 2) that are predominantly present in modern wheat does not represent the primary factor contributing to the observed variation in protein composition between modern and pre‐Green Revolution wheat cultivars. The extreme dwarfs Rht3 and Rht2 + 3 are not recommended to be included in wheat breeding programs due to their lower glutenin content. The high number of harvest years and biological replicates strengthen our findings. To our best knowledge, this is the first study that conducted Osborne fractionation on NILs with different Rht alleles. The semi‐dwarfing (Rht1, Rht2) and the dwarf Rht gene combination (Rht1 + 2) only had a small effect on protein composition. The extreme dwarfing genes (Rht3 and Rht2 + 3) decreased glutenin content leading to higher gliadin‐to‐glutenin ratios compared to the tall wild‐type (rht). A strong environmental influence on the protein composition was observed.

The allelic variations of high-molecular-weight glutenin subunit locus in common wheat ( Triticum aestivum L.) markedly influence grain end-use quality. GLU - A1 , GLU - B1 , and GLU - D1 , which encode high-molecular-weight glutenin subunits, are located on the long arms of chromosomes 1A, 1B, and 1D, respectively. However, existing markers for distinguishing alleles at the GLU-A1 and GLU-D1 are limited with regard to both number and resolution. In the present study, we enhanced the utility of PCR-based allele detection by developing seven new agarose gel-based markers capable of differentiating four Glu - A1x , four Glu - D1x , and two Glu - D1y alleles. These new markers, in combination with previously published PCR markers, were used to successfully identify the Glu - A1 × 1 , Glu - A1 x 2 *, Glu - A1 x 2.1 *, and Glu - A1x-null alleles and the Glu - D1 x 5 , Glu - D1 x 2 , Glu - D1 x 2.1 , and Glu - D1 x 2.2 alleles across 25 wheat resources. Additionally, we developed a novel marker that enables us to distinguish between the Glu - D1y10 and Glu - D1y12 alleles more clearly than conventional markers. These improved PCR markers represent a reliable and efficient tool for detecting allelic variations at the GLU-A1 and GLU-D1 loci. They are expected to serve as valuable resources for marker-assisted selection and marker-assisted backcrossing aimed at improving the processing quality of wheat.

Key messageWe evaluated the potential of wheat wild relatives for the improvement in grain quality characteristics including micronutrients (Fe, Zn) and gluten and identified diploid wheats and the timopheevii lineage as the most promising resources.Domestication enabled the advancement of civilization through modification of plants according to human requirements. Continuous selection and cultivation of domesticated plants induced genetic bottlenecks. However, ancient diversity has been conserved in crop wild relatives. Wheat (Triticum aestivum L.; Triticum durum Desf.) is one of the most important staple foods and was among the first domesticated crop species. Its evolutionary diversity includes diploid, tetraploid and hexaploid species from the Triticum and Aegilops taxa and different genomes, generating an AA, BBAA/GGAA and BBAADD/GGAAAmAm genepool, respectively. Breeding and improvement in wheat altered its grain quality. In this review, we identified evolutionary patterns and the potential of wheat wild relatives for quality improvement regarding the micronutrients Iron (Fe) and Zinc (Zn), the gluten storage proteins α-gliadins and high molecular weight glutenin subunits (HMW-GS), and the secondary metabolite phenolics. Generally, the timopheevii lineage has been neglected to date regarding grain quality studies. Thus, the timopheevii lineage should be subject to grain quality research to explore the full diversity of the wheat gene pool.