Congruity of the Polymorphisms in the Expressed and Noncoding Parts of the <i>Gli-B1</i> Locus in Common Wheat

• Main Authors: Yulia Popovych, Sabina Chebotar, Viktor Melnik, Marta Rodriguez-Quijano, Laura Pascual, William John Rogers, Eugene Metakovsky
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Agronomy
• Subjects: <i>Triticum aestivum</i> L.; γ-gliadins; <i>Gli-B1</i>; polymorphism; molecular markers; PCR analysis
• Online Access: https://www.mdpi.com/2073-4395/10/10/1510

The previously defined pairs of primers GliB1.1 and GliB1.2 were found to produce three and four principal variants, respectively, of PCR sequence length for the γ-gliadin pseudogene in 46 <i>Triticum aestivum</i> L. cultivars from 15 countries carrying 19 known alleles at the <i>Gli-B1</i> locus. A congruity was established between this polymorphism, allelic sets of the <i>Gli-B1</i>-produced gliadins (especially of the electrophoretic mobility in acid gels of the encoded γ-gliadin) and the presence in the wheat genotype of the <i>Gli-B5b</i> + <i>Rg-1</i> allelic combination. Six different alleles at the <i>Gli-B1</i> locus encoding an identical γ-gliadin produced a PCR sequence of about 400 bp (GliB1.1). Nine <i>Gli-B1d</i>-carrying genotypes from four countries produced an identical sequence of about 409 bp (GliB1.2), while three cultivars with <i>Gli-B1h</i> and four with <i>Gli-B1b</i> produced three and two specific sequences, respectively, of slightly different length. Allele <i>Gli-B1j</i> might be the result of recombination between coding and noncoding DNA sequences within the <i>Gli-B1</i> locus. These observations imply that genetic diversity of the agriculturally important region of chromosome 1B marked by variants of the <i>Gli-B1</i> locus is rather limited among common wheat cultivars of the 20th century, specifically to eight principal versions. These might have been incorporated into common wheat from diverged genotypes of diploid donor(s), and, due to the scarcity of recombination, subsequently maintained relatively intact. As well as its evolutionary significance, this information is of potential use in wheat breeding and we consider it likely that novel variants of this region will be found in hitherto unstudied germplasm.