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.
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.
Seven Glu-A1m allelic variants of the Glu-A1mx genes in Triticum monococcum ssp. monococcum, designated as 1Ax2.1a, 1Ax2.1b, 1Ax2.1c, 1Ax2.1d, 1Ax2.1e, 1Ax2.1f, and 1Ax2.1g were characterized. Their authenticity was confirmed by successful expression of the coding regions in E. coli, and except for the 1Ax2.1a with the presence of internal stop codons at position of 313 aa, all correspond to the subunit in seeds. However, all the active six genes had a same DNA size although their encoding subunits showed different molecular weight. Our study indicated that amino acid residue substitutions rather than previously frequently reported insertions/deletions played an important role on the subunit evolution of these Glu-A1mx alleles. Since variation in the Glu-A1x locus in common wheat is rare, these novel genes at the Glu-A1mx can be used as candidate genes for further wheat quality improvement.
In recent years 56 accessions of Triticum timopheevii Zhuk. (2n=4x=28, AtAtGG) were characterized for the main phenotypic and resistance characters. Among these accessions 38 originated from the base species together with subspecies and varietas forms thereof, and 18 belong to the subspecies armeniacum group. After the evaluation of field assessment data gathered over 12 years, the most promising 11 accessions were selected for a crossability trial with cultivated einkorn. As a result of this trial, the accession with the highest seed set (Acc. No.: MVGB845) was chosen for the development of a new synthetic amphiploid using the same semi-dwarf line of diploid cultivated einkorn (Triticum monococcum L. ssp. monococcum 1T-1, 2n=2x=14, AmAm) as in the crossability trial. This einkorn line was bred in Martonvásár, and has both outstanding resistance and other promising phenotypic and agronomic characters.After crossing the accession MVGB845 with 1T-1, the triploid hybrids were treated with colchicine to obtain fertile progenies with a doubled genome. The newly developed synthetic hexaploid wheat breeding stock (named Triticum timococcum Kost., 2n=6x=42, AtAtGGAmAm) could ease the introgression of valuable resistance genes into bread wheat at the hexaploid level (bridge-crossing).The aim of the present research was to redevelop Triticum timococcum based on a detailed characterization of gene bank accessions, and to introduce this new material into wheat breeding.
Cultivated einkorn (Triticum monococcum L. ssp. monococcum) is an excellent source of resistance against several wheat diseases and quality parameters. Semi-dwarf einkorn lines with good crossability were identified in order to produce Triticum turgidum × T. monococcum synthetic amphiploids. Two combinations were used to develop the amphiploids: durum × einkorn and emmer × einkorn.After the genome duplication of F1 seeds, highly fertile amphiploids were developed. The AuBAm genome structure of the progenies was confirmed by genomic in situ hybridization (GISH).Lines derived from durum × einkorn and emmer × einkorn crosses were studied for agronomic performance, disease resistance and genetic variability. Both amphiploid combinations showed excellent resistance against certain wheat diseases (leaf rust, powdery mildew), but not against fusarium. The durum-based synthetic amphiploid lines showed a higher level of phenotypic diversity. The newly produced T. turgidum × T. monococcum synthetic hexaploids are promising genetic resources for wheat breeding. Selected durum × einkorn lines are currently used in bread wheat improvement to transfer the useful properties of einkorn into cultivated hexaploid wheat via ‘bridge-crossing’.