Characterization of Delta w-secalin genes from rye, triticale, and a wheat 1BL/1RS translocation line

• Published in: Journal of applied genetics Vol. 51; no. 4; pp. 403 - 411
• Main Authors: Jiang, Q-T, Wei, Y-M, Andre, L, Lu, Z-X, Pu, Z-E, Peng, Y-Y, Zheng, Y-L
• Format: Journal Article
• Language: English
• Published: 01.12.2010
• Subjects: Amino acid sequence; Celiac disease; Cereals; Chromosome translocations; Cysteine; Epitopes; Frameshift mutation; Genomes; Grain; Homology; Integration; Nucleotide sequence; Open reading frames; Pseudogenes; Secale cereale; Stop codon; Triticum aestivum
• ISSN: 1234-1983
• DOI: 10.1007/BF03208870

Sixty-two DNA sequences for the coding regions of omega-secalin ( Delta *w-secalin) genes have been characterized from rye (Secale cereale L.), hexaploid and octoploid triticale (XTriticosecale Wittmack), and wheat (Triticum aestivum L.) 1BL/1RS translocation line. Only 19 out of the 62 Delta *w-secalin gene sequences were full-length open reading frames (ORFs), which can be expressed into functional proteins. The other 43 DNA sequences were pseudogenes, as their ORFs were interrupted by one or a few stop codons or frameshift mutations. The 19 Delta *w-secalin genes have a typical primary structure, which is different from wheat gliadins. There was no cysteine residue in Delta *w-secalin proteins, and the potential celiac disease (CD) toxic epitope (PQQP) was identified to appear frequently in the repetitive domains. The Delta *w-secalin genes from various cereal species shared high homology in their gene sequences. The Delta *w-secalin gene family has involved fewer variations after the integration of the rye R chromosome or whole genome into the wheat or triticale genome. The higher Ka/Ks ratio (i.e. non-synonymous to synonymous substitutions per site) in Delta *w-secalin pseudogenes than in Delta *w-secalin ORFs indicate that the pseudogenes may be subject to a reduced selection pressure. Based on the conserved sequences of Delta *w-secalin genes, it will be possible to manipulate the expression of this gene family in rye, triticale, or wheat 1BL/1RS translocation lines, to reduce its negative effects on grain quality.