Authors:S. Keskin Şan, Ö. Özbek, V. Eser, and B. Göçmen Taşkin
The objective of this study is the analysis of polymorphism in seed endosperm proteins (gliadins and glutenins) of Turkish cultivated einkorn wheat [Triticum monococcum ssp. monococcum] landraces. The genetic diversity of high-molecular-weight (HMW) glutenin subunits and the gliadin proteins in 10 landrace populations of cultivated einkorn wheat, originating from Turkey, was investigated using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and ammonium lactic acid polyacrylamide gel electrophoresis (A-PAGE), respectively. For glutenins, the mean number of alleles, the mean number of effective alleles, the mean value of genetic diversity and the mean value of average genetic diversity were detected as 3.50, 2.98, 0.65 and 0.28, respectively. The genetic differentiation was 0.57, while gene flow was 0.19 between populations. For gliadins, the mean number of alleles, the mean number of effective alleles, the mean value of total genetic diversity and the genetic diversity within population were detected as 2.00, 1.21, 0.17 and 0.15, respectively. The genetic differentiation was 0.08, whereas gene flow was 6.15 between populations. STRUCTURE is a software package program for population genetic analysis, was used to infer population structures of landraces populations. The optimum value for K was obtained as 10. Considering the high number of proteins and genetic variation, and increased interest in organic products, the farming of einkorn wheat should be supported and conservation of germplasm in landraces should be maintained as important genetic resources. The landraces germplasm should be conserved for future crop improvement processes.
Authors:G. Balázs, S. Tömösközi, A. Harasztos, V. Németh, Á. Tamás, A. Morgounov, I. Belan, W. Ma, and F. Békés
Based on previous research on validating lab-on-a-chip data on wheat protein analysis, a comprehensive work has been carried out with the intent to demonstrate the potential of the technique for wheat related fundamental research, breeding and food industry. Sample preparation and separation methodologies were investigated for the main wheat polypeptide classes: albumins, globulins, gliadins and glutenin subunits (GS). The work was carried out on a sample population originated from Western Siberia with different genetic background providing data, and characterizing their potential interest for future breeding work. LOC results are compared with corresponding reference methods (MALDI-TOF and RP-HPLC). The research revealed that, the current technology is capable for fast profile analysis, recognizing the minor qualitative, and typical quantitative differences in the albumin and globulin protein composition. While the gliadin separation showed poor results, the method seems to be able to identify the high molecular glutenin allelic composition, and to differentiate some of the low molecular weight glutenin alleles, too. Our results provide new insights into a possible rapid and simple way for grain protein profiling.
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.
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.
This study was undertaken to investigate the allelic diversity in seed storage proteins in 11 substituted hexaploid triticale cultivars (all spring). These cultivars were developed at the Cereal Institute of Thessaloniki, Hellas, in the 1970s and 1980s, after selection on segregating material originating from International Maize and Wheat Improvement Center (CIMMYT). Seeds from each line were used to determine alleles at the loci for high molecular weight glutenin subunits (HMW-GS)
Glu-A1, Glu-B1, Glu-R1
) and gliadins (the loci
). For this to be done, acid polyacrylamide gel electrophoresis for gliadins and SDS-electrophoresis for high molecular weight glutenins (HMW-GS) were applied. Analysis of the electrophoretic patterns obtained from the above-mentioned material revealed that only 5 out of the 11 cultivars were biochemically uniform (cv. ‘Vryto’, ‘Thisvi’, ‘Dada’, ‘Leto’ and ‘Ekate’). On the contrary, the rest of the cultivars, despite they were under seed production process, exhibited heterogeneity. Cv. ‘Dada’, which was found to be uniform, is of special interest, due to its productivity, especially under drought stress conditions.
High-molecular-weight glutenin subunits (HMW-GSs) are important seed storage proteins associated with bread-making quality in common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD). Variation in the Glu-A1x locus in common wheat is scare. Diploid Triticum monococcum ssp. monococcum (2n = 2x = 14, AmAm) is the first cultivated wheat. In the present study, allelic variations at the Glu-A1mx locus were systematically investigated in 197 T. monococcum ssp. monococcum accessions. Out of the 8 detected Glu-A1mx alleles, 5 were novel, including Glu-A1m-b, Glu-A1m-c, Glu-A1m-d, Glu-A1m-g, and Glu-A1m-h. This diversity is higher than that of common wheat. Compared with 1Ax1 and 1Ax2*, which are present in common wheat, these alleles contained three deletions/insertions as well as some single nucleotide polymorphism variations that might affect the elastic properties of wheat flour. New variations in T. monococcum probably occurred after the divergence between A and Am and are excluded in common wheat populations. These allelic variations could be used as novel resources to further improve wheat quality.
Authors:A. shahnejat Bushehri, A. Salavati, B. yazdi Samadi, M. Hassani, and S. Shahnejat Bushehri
D’Ovidio, R., Porceddu, E., Lafiandra, D. 1994. PCR analysis of genes encoding allelic variants of high-molecular-weight gluteninsubunits at the Glu-D1 locous. Theor. Appl. Genet. 88 :175–180.