Authors:M. Demichelis, L.S. Vanzetti, J.M. Crescente, M.M. Nisi, L. Pflüger, C.T. Bainotti, M.B. Cuniberti, L.R. Mir, and M. Helguera
Seed storage proteins (gliadins and glutenins) play a key role in the determination of dough and bread-making quality in bread wheat. This is due to the interaction between high and low molecular weight glutenins subunits and gliadins, via complex inter- and intramolecular bondings. In contrast to high molecular weight glutenins, low molecular weight glutenins and gliadins analysis is difficult due to the large number of expressed subunits and coding genes. For these reasons the role of individual proteins/subunits in the determination of wheat quality is less clear. In this work we studied the effect of gene clusters Glu-A3/Gli-A1 and Glu-D3/Gli-D1 in bread-making quality parameters using 20 F4-6 families from the cross Prointa Guazú × Prointa Oasis, both cultivars carrying identical high molecular weight glutenins subunits composition and presence of 1BL/1RS wheat-rye translocation, but differing in Glu-A3/Glu-D3 low molecular weight glutenins subunits and Gli-A1/Gli-D1 gliadins patterns. ANCOVA analysis showed a significant contribution of the Glu-D3/Gli-D1 gene cluster provided by Prointa Guazú to gluten strength explained by mixograph parameters MDS and PW, and Zeleny Test. Markers tagging Prointa Guazú Glu-D3/Gli-D1 alleles are available for strong gluten selection in breeding programs.
Authors:L. Wei, S.G. Bai, X.J. Hou, J.M. Li, B. Zhang, W.J. Chen, D.C. Liu, B.L. Liu, and H.G. Zhang
Anjum F.M., Khan M.R., Din A., Saeed M., Pasha I., Arshad M.U. 2007. Wheat gluten: High molecular weight gluteninsubunits — Structure, genetics, and relation to dough elasticity. J. Food Sci. 72 :R56–R63
Ultracentrifugation was used as a non-destructive method to separate dough into liquid, gel, gluten, starch and bottom phases. The protein composition in the different phases was investigated for dough prepared from spring wheat (Triticum aestivum L.). The SDS-PAGE, SE-HPLC and RP-HPLC methods were used for the analysis. The wheat protein composition of the liquid and gel phases consisted of albumins, globulins and traces of gliadins and glutenins. The gluten phase contained proteins extractable with all the extraction buffers used. A similar protein composition was found in the starch and bottom phases, but in considerably lower amounts. Specific LMW glutenin subunits were identified in the gluten phase by RP-HPLC. The albumin composition differed in the gel phase compared to the gluten and bottom phases. Differences in protein composition due to mixing methods were detected only for the albumin composition in the liquid phases.
Authors:S. Elfatih, Y. Peng, J. Ma, J. Peng, D. Sun, and W. Ma
A total of 232 accessions of tetraploid species, durum wheat (Triticum turgidum L. ssp. durum Desf., 2n=4x=28, AABB) with a widespread origin of various countries were used in this study. Their high molecular weight glutenin subunit (HMW-GS) composition was identified by Matrix-assisted laser desorption/ionization time-of-flight Mass Spectrometry (MALDI-TOF-MS). Among all accessions analyzed, 194 were homogeneous for HMW-GS, 38 were heterogeneous, and 62 possessed unusual or new subunits. The results revealed a total of 43 alleles, including 5 at Glu-A1 and 38 at Glu-B1, resulting in 60 different allele combinations. The Glu-B1 locus displayed higher variation compared with Glu-A1. Glu-A1c (55.2%) and Glu-B1aj (17.7%) were the most frequent alleles at Glu-A1 and Glu-B1, respectively. Two allele types (“null” and 1) at the Glu-A1 locus and three allele types (7OE + 8, 14+15, 8) at the Glu-B1 locus appeared to be the common types in the 232 accessions. A total of 23 new alleles represented by unusual subunits were detected at the Glu-A1 and the Glu-B1 locus.
Authors:M. Rajabi Hashjin, M.H. Fotokian, M. Agahee Sarbrzeh, M. Mohammadi, and D. Talei
Knowledge of morpho-protein patterns of genetic diversity improves the efficiency of germplasm conservation and development. The objective of present study was to evaluate 116 genotypes of Triticum turgidum from seven countries in terms of morphological traits and seed protein banding patterns. The results showed highly significant differences among the genotypes for the traits. The correlation between grain yield and weight per spike was significant and positive, while the correlation between days to heading, length of peduncle and plant height was significant and negative. The factor analysis classified the traits in to four main groups which accounted for 74.4% of the total variability. Sixteen allelic compositions were identified in the genotypes for high molecular weight glutenin subunits. The three alleles were present at the Glu-A1 locus and 8 alleles at Glu-B1. The null allele was observed more frequently than the 1 and 2 alleles. Two alleles, namely 17 + 18 and 20, represented more frequent alleles at Glu-B1 locus. The genetic variability in Glu-A1and Glu-B1 loci were 0.42 and 0.81, respectively. The cluster analysis based on morphological traits and HMW-GS clustered the genotypes in to six and seven groups, respectively. The results indicated the presence of high genetic variability among the genotypes. Our findings suggest that the plants belong to different clusters can be used for hybridization to generate useful recombinants in the segregating generations, the genetics and breeding programs for improvement of durum wheat.
Premature termination codons (PTCs) are an important reason for the silence of highmolecular- weight glutenin subunits in Triticum species. Although the Glu-A1y gene is generally silent in common wheat, we here isolated an expressed Glu-A1y gene containing a PTC, named 1Ay8.3, from Triticum monococcum ssp. monococcum (AmAm, 2n = 2x = 14). Despite the presence of a PTC (TAG) at base pair positions 1879–1881 in the C-terminal coding region, this did not obviously affect 1Ay8.3 expression in seeds. This was demonstrated by the fact that when the PTC TAG of 1Ay8.3 was mutated to the CAG codon, the mutant in Escherichia coli bacterial cells expressed the same subunit as in the seeds. However, in E. coli, 1Ay8.3 containing the PTC expressed a truncated protein with faster electrophoretic mobility than that in seeds, suggesting that PTC translation termination suppression probably occurs in vivo (seeds) but not in vitro (E. coli). This may represent one of only a few reports on the PTC termination suppression phenomenon in genes.