The influence of Glu-1 and Glu-3 loci on dough rheology and bread-making properties in wheat (Triticum aestivum L.) doubled haploid lines

BACKGROUND

The major determinants of wheat quality are Glu-1 and Glu-3 glutenin loci and environmental factors. Additive effects of alleles at the Glu-1 and Glu-3 loci, as well as their interactions, were evaluated for dough rheology and baking properties in four groups of wheat doubled haploid lines differing in high- and low-molecular-weight glutenin composition.

RESULTS

Flour quality, Reomixer (Reologica Instruments, Lund, Sweden), dough extension, Farinograph (Brabender GmbH, Duisburg, Germany) and baking parameters were determined. Groups of lines with the alleles Glu-A3b and Glu-B3d were characterized by higher values of dough and baking parameters compared to those with the Glu-A3e and Glu-B3a alleles. Effects of interactions between allelic variants at the Glu-1 and Glu-3 loci on Reomixer parameters, dough extension tests and baking parameters were significant, although additive effects of individual alleles were not always significant.

CONCLUSION

The allelic variants at Glu-B3 had a much greater effect on dough rheological parameters than the variants at Glu-A3 or Glu-D3 loci. The effect of allelic variations at the Glu-D3 loci on rheological parameters and bread-making quality was non-significant, whereas their interactions with a majority of alleles at the other Glu-1 × Glu-3 loci were significant. © 2017 Society of Chemical Industry.

Rheological characterisation of gluten from triticale (x Triticosecale Wittmack)

BACKGROUND

Triticale gluten still remains very poorly characterised rheologically. In this study the mechanical spectra of gluten isolated from four triticale cultivars were registered and fitted with Cole-Cole functions yielding the visco-elastic plateau parameters. Master spectra were calculated. A retardation test was performed and used to calculate the composite mechanical spectra and the width of visco-elastic plateau l. Protein fractional composition of triticale flour and gluten was studied using capillary zone electrophoresis.

RESULTS

Differentiated HMW-GS/SS compositions were identified in the triticale cultivars studied. The rheological parameters reached the following values: J_N⁰ 1.05·10^-3 to 2.69·10^-3 Pa^-1 , G_N⁰ 372 to 956 Pa, ω₀ 0.003 to 0.06 rad s^-1 , l 169 to 3121, J_e⁰ 1.57·10^-3 to 5.03·10^-3 Pa^-1 , G_e⁰ 199 to 637 Pa and η₀ 1.06·10⁷ to 3.93·10⁷ Pa s.

CONCLUSIONS

Visco-elastic properties of triticale gluten correspond to the lower end of medium visco-elasticity shown by common wheat gluten. Master spectra and the composite mechanical spectra prove that four triticale glutens exhibit practically an identical type of visco-elastic behaviour of a biopolymeric visco-elastic liquid similar to wheat gluten. The visco-elastic plateau parameters G_N⁰ , J_N⁰ , ω₀ and l appeared significantly correlated with the contents of prolamins and secaloglutenins in triticale flours and glutens. © 2017 Society of Chemical Industry.

Grain quality characteristics and dough rheological properties in Langdon durum-wild emmer wheat chromosome substitution lines under nitrogen and water deficits

BACKGROUND

Wild emmer wheat could serve as a source of novel variation in grain quality and stress resistance for wheat breeding. A set of Triticum durum-T. dicoccoides chromosome substitution lines [LDN(DIC)] and the parental recipient cv. Langdon grown under contrasting water and nitrogen availability in the soil was examined in this study to identify differences in grain quality traits and dough rheological properties.

RESULTS

Significant genotypic variation was found among the materials for studied traits. This variation was also considerably affected by soil treatments and G × E interactions. The substitutions LDN(DIC-1A) and LDN(DIC-1B) showed separate differentiation in the composition of glutenin sub-units. The results indicated that primarily chromosome DIC-6B is stable source of an enhanced grain protein content and advantageous dough rheological properties. Similar features seem to be shown by the substitutions with the DIC-1A, DIC-2A and DIC-6A, but not under nitrogen shortage, when generally a considerable decrease was noticed in the range of genotypic variation in grain quality.

CONCLUSIONS

The substitution lines, particularly those with DIC-6B and DIC-6A and to a lesser extent DIC-1A and DIC-2A, were distinguished by advantageous grain quality traits, mixing properties and dough functionality and appear to be the most promising sources of innovative genes for wheat breeding. © 2016 Society of Chemical Industry.

Interactions between Glu-1 and Glu-3 loci and associations of selected molecular markers with quality traits in winter wheat (Triticum aestivum L.) DH lines

The quality of wheat depends on a large complex of genes and environmental factors. The objective of this study was to identify quantitative trait loci controlling technological quality traits and their stability across environments, and to assess the impact of interaction between alleles at loci Glu-1 and Glu-3 on grain quality. DH lines were evaluated in field experiments over a period of 4 years, and genotyped using simple sequence repeat markers. Lines were analysed for grain yield (GY), thousand grain weight (TGW), protein content (PC), starch content (SC), wet gluten content (WG), Zeleny sedimentation value (ZS), alveograph parameter W (APW), hectolitre weight (HW), and grain hardness (GH). A number of QTLs for these traits were identified in all chromosome groups. The Glu-D1 locus influenced TGW, PC, SC, WG, ZS, APW, GH, while locus Glu-B1 affected only PC, ZS, and WG. Most important marker-trait associations were found on chromosomes 1D and 5D. Significant effects of interaction between Glu-1 and Glu-3 loci on technological properties were recorded, and in all types of this interaction positive effects of Glu-D1 locus on grain quality were observed, whereas effects of Glu-B1 locus depended on alleles at Glu-3 loci. Effects of Glu-A3 and Glu-D3 loci per se were not significant, while their interaction with alleles present at other loci encoding HMW and LMW were important. These results indicate that selection of wheat genotypes with predicted good bread-making properties should be based on the allelic composition both in Glu-1 and Glu-3 loci, and confirm the predominant effect of Glu-D1d allele on technological properties of wheat grains.

Variation of high-molecular-weight secalin subunit composition in Rye (Secale cereale L.) inbred lines

In this study, identification and characterization of the rye HMW secalin subunit (HMW-SS) composition in 68 inbred rye (Secale cereale L.) lines was performed by capillary zone electrophoresis (CZE). The HMW-SS were separated in an uncoated fused-silica capillary using an isoelectric iminodiacetic buffer in combination with poly(ethylene oxide), lauryl sulfobetaine, and acetonitrile as the separation buffer. The separations of the nonalkylated HMW-SS provided very good resolution and high reproducibility. Generally, the x-type rye HMW-SS were more abundant and have longer migration times than the y-type subunits. Both types of rye HMW-SS were separated into the major protein peak and one or two minor peaks. In total, seven x-type HMW-SS, five of which were newly identified subunits, and six y-type subunits, four of which were new, were distinguished on the basis of their CZE migration times. The migration order of the rye HMW-SS using CZE differed considerably from the relative electrophoretic mobilities in the SDS-PAGE gels.

Charge-based characterisation of high-molecular-weight glutenin subunits from common wheat by capillary isoelectric focusing

In this study, the capillary isoelectric focusing (CIEF) method for the separation and charge characterisation of the heterogeneity of high molecular-weight-glutenin subunits (HMW-GS) in common wheat (Triticum aestivum L.) using linear polyacrylamide (LPA) and polyvinyl alcohol (PVA) coated capillaries was developed. Particularly good repeatability and well-resolved charge isoform profiles were obtained by introducing a mixture of carrier ampholytes (pH 3-10 and pH 5-8), a high concentration of urea (6M) and SB3-12 as detergent in a sample solution during separation in a PVA-coated capillary. One major and one or two minor isoforms were observed for the individual HMW-GS. These isoforms were satisfactorily separated using a pH gradient into two groups: y-type isoforms and x-type isoforms encoded by the Glu-B1 locus with shorter migration times and remaining x-type isoforms with longer times. The method produced from eight to twelve isoforms of wheat HMW-GS with pI points in the range of 4.72-6.98. Generally, the minor isoforms were more acidic compared with the major isoform. The y-type subunits had an approximately neutral character (pI 6.70-6.98); however, x-types showed a weakly acidic character (pI 4.72-5.23), with the exception of subunits encoded by the Glu-B1 locus. The isoelectric point peak profiles were compared with capillary zone electrophoresis (CZE) electropherograms. Generally, the number of detected isoforms for the particular HMW-GS detected using both methods were similar.

CE determination of secaloindoline allelic forms in hexaploid triticale (x Triticosecale Wittmack)

Differences in kernel texture are mainly caused by specific secaloindoline (SIN) proteins occurring in friabilin fraction of hexaploid triticale (x Triticosecale Wittmack) grain. SINs were isolated using Triton X-114 partitioning from either kernels/flour or starch of five triticale cultivars with wide range of different hardness. Crude SIN fraction was obtained by size-exclusion HPLC. SINs were separated on an uncoated fused-silica capillary using the iminodiacetic (IDA) buffer in conjunction with lower-concentrated poly(ethylene oxide) and ACN. A low-concentrate mixture of hydrophilic polymers, PVP and hydroxypropylmethylcellulose in IDA buffer was employed for dynamic coating of capillary inner wall. In total, on the basis of CZE profiles, two SIN-a proteins and two SIN-b proteins were identified. Allelic forms SIN-a1 and SIN-b1 have both two soft and one medium hard genotypes, however other allelic forms, designed as SIN-a2 and SIN-b2, were identified in hard and other medium hard cultivars. The CZE profiles showed that the ratio of the peak areas of SIN-b proteins isolated from triticale starch can be preliminarily used to distinguish cultivars with soft and hard grain.

Diversity of monomeric prolamins in triticale cultivars determined by capillary zone electrophoresis

Capillary zone electrophoretic (CZE) analysis of monomeric prolamins (wheat gliadins and rye secalins) covered 28 hexaploid triticale ( Triticosecale x Wittm.) cultivars. The ethanol-soluble proteins were separated on an uncoated fused-silica capillary using the isoelectric 60 mM iminodiacetic (IDA) buffer in conjunction with 20% (v/v) acetonitrile and 0.075% (w/v) polyvinylpyrrolidone (PVP). For each separation, dynamic coating of the capillary wall with a buffer containing 0.1 M IDA and 0.05% (w/v) hydroxypropylmethylcellulose (HPMC) was performed. Separations of prolamins provided very good resolution and high reproducibility (<0.8% RSD). Prolamin profiles of all analyzed cultivars showed both qualitative and quantitative differences, including number of peaks, presence or absence of peaks, and area of peaks. The number of prolamin peaks detected in particular triticale cultivars varied from 22 to 28; in total, 56 components were distinguished. The CZE electropherograms of prolamins showed five main groups of protein peaks, in order of mobility alpha-prolamins, beta-prolamins, gamma-prolamins, omega1-prolamins, and omega2-prolamins, with migration times of 6.8-7.7, 7.8-10.4, 10.5-12.2, 12.3-17.4, and 17.5-25.6 min, respectively. Triticale seeds in comparison with wheat contained fewer alpha-prolamins and higher quantity of omega-prolamins. Hierarchical clustering of the investigated cultivars was based on Bhattacharyya distances calculated from the CZE data. The cultivars grouped in four main clusters. The obtained CZE results were compared with A-PAGE data.

Detection of high molecular weight glutenin subunits in triticale (x Triticosecale Wittm.) Cultivars by capillary zone electrophoresis

An improved method for separating and characterizing high molecular weight glutenin subunits (HMW-GS) in hexaploid triticale by capillary zone electrophoresis (CZE) was developed. A low-concentrate mixture of hydrophilic polymers, poly(vinylpyrrolidone) (PVP) and hydroxypropylmethylcellulose (HPMC), in an isoelectric buffer was employed for dynamic coating of the capillary inner wall. In separation buffer PVP with lower concentrated poly(ethylene oxide) (PEO) was replaced. The CZE electropherograms of HMW-GS showed two group peaks in accordance with x- and y-type subunits with migration times of 6.8-7.8 and 8.4-11.5 min, respectively. In total, 14 HMW subunits (2 subunits encoded by Glu-A1 locus and 12 by Glu-B1) were identified. The CZE analyses revealed that each of the subunits Bx7 and By8 determined by SDS-PAGE makes up three subunits (Bx6.8, Bx7, and Bx7* and By8, By8*, and new By8**, respectively), with different migration times. It was also shown that the subunits By18 and By20 in triticale determined by SDS-PAGE have different migration times in comparison with the same subunits in bread wheat. For these new HMW-GS, the following names were assigned: By18* instead of By18 and By20* instead of By20. The presented CZE method is an efficient alternative to the SDS-PAGE procedure for early selection of useful triticale genotypes with good breadmaking quality.

Multiplex PCR identification of wheat HMW glutenin subunit genes by allele-specific markers

Wheat bread-making quality is closely correlated with composition and quantity of gluten proteins, in particular with high-molecular weight (HMW) glutenin subunits encoded by the Glu-1 genes. A multiplex polymerase chain reaction (PCR) method was developed to identify the allele composition of HMW glutenin complex Glu-1 loci (Glu-A1, Glu-B1 and Glu-D1) in common wheat genotypes. The study of multiplex PCR to obtain a well-balanced set of amplicons involved examination of various combinations of selected primer sets and/or thermal cycling conditions. One to three simultaneously amplified DNA fragments of HMW glutenin Glu-1 genes were separated by agarose slab-gel electrophoresis and differences between Ax1, Ax2* and Axnull genes of Glu-A1 loci, Bx6, Bx7 and Bx17 of Glu-B1, and Dx2, Dx5 and Dy10 genes of Glu-D1 loci were revealed. A complete agreement was found in identification of HMW glutenin subunits by both multiplex PCR analysis and SDS-PAGE for seventy-six Polish cultivars/strains of both spring and winter common wheat. Rapid identification of molecular markers of Glu-1 alleles by multiplex PCR can be an efficient alternative to the standard separation procedure for early selection of useful wheat genotypes with good bread-making quality.

Phaseolin seed variability in common bean (Phaseolus vulgaris L.) by capillary gel electrophoresis

Phaseolin, the major seed storage protein of Phaseolus vulgaris from forty-four wild and cultivated accessions, was studied using sodium dodecyl sulphate-capillary gel electrophoresis (SDS-CGE). In total, eleven phaseolin profiles, revealing polypeptide subunit variation in the range from 45.6 kDa to 54.4 kDa, were recorded. The number of polypeptide subunits recorded in particular profiles varied from 3 to 6; in total, eight phaseolin subunits were distinguished in the examined material. Ferguson plot analysis was used to correct non-ideal behaviour of phaseolin polypeptide subunits in capillary gel electrophoresis in the presence of SDS. The obtained results are compared to electrophoretic data received by slab polyacrylamide gel electrophoresis. The SDS-CGE method appears to provide a powerful tool for disclosure of phaseolin subunit variability.

Capillary electrophoresis of seed 2S albumins from Lupinus species

Two modes of capillary electrophoresis (CE)--free-solution capillary zone electrophoresis (CZE) and sodium dodecyl sulfate capillary electrophoresis (SDS-CE) using a non-gel sieving matrix--have been developed for comparative analysis of low-molecular-mass 2S albumin isoforms from lupins. The albumin fraction and 2S albumins were separated in uncoated fused-silica capillary by CZE with 0.02 M phosphate buffer, pH 7.3, containing the sodium salt of phytic acid. The use of phytic acid (0.025 M) as buffer modifier and ion-pairing agent improved migration reproducibility, peak shape and separation efficiency. The reduced 2S albumins were separated by SDS-CE using a high concentration (0.3-0.5 M) mixture of tris(hydroxymethyl)aminomethane and borate buffers in uncoated fused-silica capillary. Of the various polymers used as non-gel sieving matrix, SDS-CE with a 10% dextran solution was found to be suitable for separation of 2S albumin polypeptides with molecular masses of 4,000-7,000 and 8,000-11,000. The addition of glycerol or ethylene glycol to the SDS separating buffer improved the resolution of polypeptides. The examined Lupinus species showed species-specific CZE and SDS-CE migration profiles of the 2S albumins.