Authors:Z. Yan, S. Dai, D. Liu, Y. Wei, and Y. Zheng
A novel HMW-GS of Dx5** with slightly faster migration rate than that of Dx5, was found in a Tibet bread wheat landrace using SDS-PAGE. Moreover, Dx5** is the subunit with the fastest migration rate in
locus. The gene for this subunit was isolated and its sequence was obtained in the present study. This gene was very similar to Dx5 both in nucleotide and deduced amino acid sequence. At the nucleotide sequence level, Dx5** different from Dx5 by the deletion of a 27 bp fragment and two nucleotide replacements at position 353(G/C) and 692(C/G), respectively. At the amino acid sequence level, Dx5** different from Dx5 by the deletion of a hexaploid (LGQGQQ) and a tripeptide (GQQ) repetitive motif and two amino acid replacements at position 118(C/S) and 231(A/G), respectively. These results suggested that the Dx5** was a derivation of Dx5 and was formed by replication slippage. Moreover, the specific cysteine (C) located at the beginning of the repetitive domain of Dx5, which proved to be critical for the end-use quality of wheat flours, was replaced by serine (S) in Dx5**.
Authors:Ž. Kurtanjek, D. Horvat, G. Drezner, and D. Magdić
Gluten proteins composed of gliadins and glutenins are important contributors to the wheat quality properties. Twenty-eight winter wheat cultivars differing in bread processing quality were collected at the experimental fields of the Agricultural Institute Osijek, Croatia, in growing season 2006/2007.The HMW-GS composition and gliadin contents were determined by SDS-PAGE and RP-HPLC, respectively, with the aim to determine their relationship with wheat quality properties. Based on gliadins and HMW-GS data for 28 wheat cultivars PLS models were developed for the prediction of 15 baking quality parameters.NIPALS algorithm was applied for the evaluation of the latent variables and regression coefficient parameters. The obtained 4-th order models have average coefficients of determination R2=0.80.Determined variable importance in projections (VIP) coefficients revealed that HMW-GS data have the dominant influence on the baking quality parameters. For extensographic and farinographic properties the Glu-D1 locus has the main VIP coefficient while Glu-B1 locus is the most important for the indirect quality parameters. The derived PLS models and VIP coefficients could be used in molecular based wheat selection and breeding program.
Authors:S.F. Dai, D.Y. Xu, Z.J. Wen, Z.P. Song, H.X. Chen, H.Y Li, J.R. Li, L.Z. Kang, and Z.H. Yan
A novel 4.0-kb Fy was sequenced and bacterially expressed. This gene, the largest y-type HMW-GS currently reported, is 4,032-bp long and encodes a mature protein with 1,321 amino acid (AA) residues. The 4.0-kb Fy shows novel modifications in all domains. In the N-terminal, it contains only 67 AA residues, as three short peptides are absent. In the repetitive domain, the undecapeptide RYYPSVTSPQQ is completely lost and the dodecapeptide GSYYPGQTSPQQ is partially absent. A novel motif unit, PGQQ, is present in addition to the two standard motif units PGQGQQ and GYYPTSPQQ. Besides, an extra cysteine residue also occurs in the middle of this domain. The large molecular mass of the 4.0-kb Fy is mainly due to the presence of an extra-long repetitive domain with 1,279 AA residues. The novel 4.0-kb Fy gene is of interest in HMW-GS gene evolution as well as to wheat quality improvement with regard to its longest repetitive domain length and extra cysteines residues.
Odenbach, W., Mahgoub, El-S. 1988. Relationship between HMW-GS composition and sedimentation value in reciprocal sets of inbred backcross lines drive from two winter wheat crosses. Proc. 7
Int Wheat Genet Symp. Cambridge, pp. 987
Authors:K. Dong, C. Hao, A. Wang, M. Cai, and Y. Yan
The wheat storage proteins, especially the high molecular weight glutenin subunits (HMW-GS), play important roles in the determination of flour processing and bread-making quality. Compared with the traditional SDS-PAGE method, reversed-phase high-performance liquid chromatography (RP-HPLC) was shown to have many advantages for the separation and characterization of HMW-GS because of its high resolving power, repeatability and automation. In this work, HMW-GS from bread and tetraploid wheats were separated and characterized by RP-HPLC. The elution time ranking of different HMW-GS was: 1Ax > 1Bx > 1Dx > 1By > 1Dy. Several subunit pairs associated with good quality properties and those with similar mobilities on SDS-PAGE, such as 1Bx7 and 1Bx7*, 1By8 and 1By8*, 1Dx2 and 1Ax2*, 1Bx6 and 1Bx6.1, were well separated and readily identified through RP-HPLC. However, other subunit pairs, such as 1Dy10 — 1Dy12, 1Dx5 — 1By18 and 1Dx2 — 1By16, could not be adequately separated and identified by RP-HPLC, whereas they displayed different mobilities on SDS-PAGE gels. Because 1Dx5 and 1Dx2 showed different hydrophobicities, RP-HPLC could distinguish 1Dx5 + 1Dy10 and 1Dx2 + 1Dy12. A comparative analysis between RP-HPLC and SDS-PAGE showed that a combination of both methods provided more effective identification of HMW-GS in wheat quality improvement and germplasm screening.
Authors:Z. Šramková, E. Gregová, S. Šliková, and E. Šturdík
The main goal of our work was to determine the composition of high-molecular-weight glutenin subunits (HMW-GS) in 84 cultivars of common wheat (
L.) originating from eight European countries and registered in Slovakia. Eleven alleles and 18 allelic compositions were detected. The most frequent HMW-GS patterns were “Null”, 7 + 9, 5 + 10 and “Null”, 7 + 8, 5 + 10 which were observed in twenty-seven (31%) and fourteen (16.1%) cultivars, respectively. The allele 5 + 10, which has the strongest association with good bread-making quality, was present in 75% of analysed accessions. The wheat-rye 1BL/1RS translocation was identified in eleven cultivars.