Molecular discrimination of Bx7 alleles demonstrates that a highly expressed high-molecular-weight glutenin allele has a major impact on wheat flour dough strength

Abstract

High-molecular-weight glutenin subunits (HMW-GS) are important determinants of wheat dough quality as they confer visco-elastic properties to the dough required for mixing and baking performance. With this important role, the HMW-GS alleles are key markers in breeding programs. In this work, we present the use of a PCR marker initially designed to discriminate Glu1 Bx7 and Glu1 Bx17 HMW-GS. It was discovered that this marker also differentiated two alleles, originally both scored as Glu1 Bx7, present in the wheat lines CD87 and Katepwa respectively, by a size polymorphism of 18 bp. The marker was scored across a segregating doubled-haploid (DH) population (CD87 x Katepwa) containing 156 individual lines and grown at two sites. Within this population, the marker differentiated lines showing the over-expression of the Glu1 Bx7 subunit (indicated by the larger PCR fragment), derived from the CD87 parent, relative to lines showing the normal expression of the Glu1 Bx7 subunit, derived from the Katepwa parent. DNA sequence analysis showed that the observed size polymorphism was due to an 18 bp insertion/deletion event at the C-terminal end of the central repetitive domain of the Glu1 Bx 7 coding sequence, which resulted in an extra copy of the hexapeptide sequence QPGQGQ in the deduced amino-acid sequence of Bx7 from CD87. When the DH population was analysed using this novel Bx7 PCR marker, SDS PAGE and RP HPLC, there was perfect correlation between the Bx7 PCR marker results and the expression level of Bx7. This differentiation of the population was confirmed by both SDS-PAGE and RP-HPLC. The functional significance of this marker was assessed by measuring key dough properties of the 156 DH lines. A strong association was shown between lines with an over expression of Bx7 and high dough strength. Furthermore, the data demonstrated that there was an additional impact of Glu-D1 alleles on dough properties, with lines containing both over-expressed Bx7 and Glu-D1 5+10 having the highest levels of dough strength. However, there was no statistically significant epistatic interaction between Glu-B1 and Glu-D1 loci.

Biochemical and Molecular Characterization of Bangladeshi Wheat Varieties for Bread-Making Quality

“…;2=Kalyansona;4=Sonalika;6=Balaka;7=Ananda;8=Kanchan;9=Akbar;10=Barkat;11=Aghrani;12=Protiva;13=Sourav;14=Gaurav;15=Shatabdi;16=Sufi;17=Bijoy;18=Prodip;19=BARI Gom25;20=BARI Gom 26;21=BARI Gom 27;22=BARI Gom 28;23=Mulika;24=Paragon;25=Westonia 5907;26=Westonia 5924; L = DNA ladder]. Marchylo et al 1992 andButow et al 2003 stated that Bx7 enhanced dough quality, although quality score of Bx7 is very low (1) according to (Payne et al 1987). Most of the (94.44%) Bangladeshi genotypes possess Bx7 allele that can contribute in enhancing dough quality.…”

Effect of different water supply on accumulation of high molecular weight glutenin subunits and glutenin macropolymers in near-isogenic wheat lines

“…This subunit contains two more cysteine residue than subunit 26 and 20x (Naeem et al 2012). Butow et al (2003) proposed that the 643 bp insertion in the DNA matrix attachment region of 1Bx7 alleles increased transcriptional efficiency. …”

Relationship between the Dough Quality and Content of Specific Glutenin Proteins in Wheat Mill Streams, and Its Application to Making Flour Suitable for Instant Chinese Noodles

“…8,10,13,29) In order to estimate the strength of the dough, the peak time was determined by using a mixograph analysis. Since the peak time is the time until the dough reaches its maximun resistance, a stronger dough tends to have a longer peak time.…”

“…Thus, the properties and amounts of specific proteins such as high-molecularweight and low-molecular-weight glutenin subunits are important for improving the dough and end-product quality. [5][6][7][8][9][10][11][12][13] The milling of wheat grain to produce flour is not achieved in one step, a sequence of many kinds of milling and filtration processes resulting in a large number of fraction mill streams. The final flour is then obtained by combining these various mill streams, so it is valuable for wheat millers and food manufacturers to get information concerning the precise relationship between the specific proteins in a mill stream and both the dough quality and end-product.…”