Genetic Characterization of Rainfed Durum Wheat Genotypes Based On Functional Markers Associated With Grain Quality Proteins

Analysis of genetic diversity provides helpful information necessary to develop the breeding and conservation strategies of crops. In this study, the genetic diversity and population structure of 90 durum wheat genotypes maintained at Sararud Dryland Agricultural Research Institute, Kermanshah, Iran, were evaluated by using 23 gene-specific markers (functional markers, FMs) encoding high and low molecular weight glutenin and gliadin alleles. Results showed that 12 out of the 23 FMs used were polymorphic and amplified 52 polymorphic loci. Primer Ax2 ⃰ had the highest discriminatory power. The population structure analysis classified the durum wheat collection into four populations. On average, population 4, consisting of 8 genotypes, had the highest allele number as well as genetic variation. Analysis of molecular variance indicated that 82% of the total variation was distributed among populations. The diversity among populations and gene flow were 0.14 and 3.03, respectively. The Jaccard distance coefficient revealed that genetic dissimilarities ranged from 0.031 between G62 and G65 to 0.725 between G36 and G51. Neighbor-joining method clustered individuals into six main groups. Results showed a remarkable level of genetic diversity among studied durum wheat genotypes which can be of interest for future breeding programs.

Genetic diversity of ukrainian wheat landraces Triticum aestivum L. at gliadin-coding loci

Aim. The aim of the study was to investigate genetic variability of gliadin-coding loci Gli-A1, Gli-B1, Gli-D1 in Ukrainian winter common wheat landraces and obsolete varieties. Methods. APAG electrophoresis of gliadin was used to identify genotypes at Gli-1 loci. Results. Diversity at the Gli-1 loci of 41 winter common wheat landraces, including local varieties Krymka, Banatka, Girka, Theyka, and 13 obsolete winter common wheat varieties, were studied. A total 31 gliadin alleles (including new 7 alleles) were revealed. There are 11 alleles at the Gli-A1 loci, 14 - at the Gli-B1, 6 -at the Gli-D1. Differences in frequencies of gliadin alleles were established. Conclusions. The high level of allelic variation at the Gli-1 loci was observed in Ukrainian winter common wheat landraces. Predominant alleles were revealed: Gli-A1m (46,8 %), Gli-A1d (21 %), Gli-B1b (47,1 %), Gli-D1g (45,8 %), Gli-D1a (33,3 %), Gli-D1j (13,9 %). In genotype of modern Ukrainian winter common wheat are present only 3 of them - Gli-B1b, Gli-D1g, Gli-D1j, which positively relate to dough quality. Keywords: Triticum aestivum L., winter wheat, landraces, gliadin , alleles , polymorphism

Intra-varietal polymorphism of gliadins and glutenins within wheat varieties grown in the Czech Republic and its impact on grain quality

Using vertical electrophoresis, a set of 22 biotypes heterogeneous according to their gliadin alleles as well as their low-molecular-weight (LMW) and high-molecular-weight (HMW) glutenin subunits were identified in 10 winter wheat varieties registered in the Czech Republic. The effects of individual biotypes and their specific allelic compositions on 16 grain quality parameters were investigated. Inter-varietal differences in particular quality parameters (Zeleny sedimentation, farinograph water absorption, several values of the solvent retention capacity test) were significantly greater than the differences detected among biotypes of each variety. Special attention was given to the LMW glutenin subunits and gliadin alleles and to mutual interactions responsible for significant differences in the tested grain parameters. The results revealed at least one case of significant differences in grain quality parameters among biotypes of eight heterogeneous wheat varieties. This work unambiguously indicates that the high prevalence of wheat biotype(s) with significantly poorer values in some grain parameters can also decrease the expected technological quality of the original wheat variety. In particular, multi-line wheat varieties carrying alleles Glu-B1 (6+8) and Glu-B1 (7+9) or Glu-B3j and Glu-B3g can indicate the possibility of some significant changes in grain quality parameters.

Assessment of Frost Tolerance of Wheat Doubled Haploids by Gliadin Electrophoresis

The relationship between gliadin alleles, known to mark frost tolerance, and actual frost tolerance was investigated in 52 doubled haploids (DH) from the cross Florida× Vlada. Frost tolerance was expressed as percentage of plant winter survival in pots placed at different heights above the ground. Gliadin allelic blocks (GLI) were determined by starch electrophoresis. From the six GLI, known as frost tolerance markers, the GLI 1B1, GLI 1D5 or GLI 6D2 was present in 27, 27 or 31 DH, respectively. A weak, but significant correlation of r = 0.29 was found in the DH between their survival and frost tolerance prediction values based on the presence of the gliadin frost tolerance markers. The average survival of DH with gliadin frost tolerance marker GLI 1B1 or GLI 6D2, but not with GLI 1D5, was significantly higher than the survival of DH without this block. The DH without any gliadin frost tolerance marker had the lowest survival. Some gliadin genes thus can be used as frost tolerance markers for preliminary selection of frost tolerant lines and for the study of physiological and genetic constitution of frost tolerance in common wheat.

Are Ancient Durum Wheats Less Toxic to Celiac Patients? A Study ofα-Gliadin from Graziella Ra and Kamut

In the present paper, the controversial hypothesis suggesting ancient grains might show lower immunogenic properties and therefore the possibility to introduce them in the diet of wheat-sensitive people, including celiac patients, was investigated. The immunogenic potential of the ancient durum wheats Graziella Ra and Kamut was studied by comparison to the durum accessions Cappelli, Flaminio, Grazia and Svevo. Experiments were carried out with two monoclonal antibodies (mAbs) raised againstα-gliadin peptides p31–49 and p56–75 (the latter containing the overlapping DQ2-Glia-α1 and DQ2-Glia-α2 epitopes), toxic for celiac patients. For all accessions, a fewα-gliadin alleles were also cloned, sequenced and translated into aminoacid sequences. Several aminoacid substitutions or deletions were detected in p31–49, DQ2-Glia-α1 and DQ2-Glia-α2 epitopes, nevertheless, ELISA constantly showed antibody-antigen positive reactions which led us to suggest that mAbs binding was not apparently affected by polymorphisms. Moreover, a few substitutions were also observed in DQ2-Glia-α3 and DQ8-Glia-α1 epitopes. Although some DQ2-Glia-α1 and DQ2-Glia-α2 variants evidenced herein were previously reported to have a diminished or abolished T cell stimulatory capacity, present results cannot confirm that ancient durum wheats would be less CD-toxic. In conclusion, we strongly advice celiac patients from consuming ancient wheats including Graziella Ra or Kamut.

Similarity of cultivars of wheat (Triticum durum) on the basis of composition of Gliadin alleles

Twenty one durum wheat cultivars originating from different world countries were investigated. Composition of gliadins was analyzed by acid polyacrylamide gel electrophoresis. Allele composition of gliadins was determined on the basis of identified gliadin blocks. Polymorphisms of Gli- loci was established and 27 different gliadin alleles were identified, namely, 5 at Gli-A1, 4 at Gli-B1, 9 at Gli-A2 and 9 alleles at Gli-B2 locus. The catalogue of determined alleles was presented. Frequency of alleles ranged from 4.76% to 42.86%. Heterozygous Gli-loci were identified at two durum cultivars. Similarity among cultivars was studied on composition of Gli-alleles and presented by UPGMA dendogram. On the base of Gli-allele composition, similarity varied from 0% to 100%.