Characterization of &omega;-secalin genes from rye, triticale, and a wheat 1BL/1RS translocation line.
Sixty-two DNA sequences for the coding regions of omega-secalin (ω-secalin) genes have been characterized from rye (Secale cereale L.), hexaploid and octoploid triticale (× Triticosecale Wittmack), and wheat (Triticum aestivum L.) 1BL/1RS translocation line. Only 19 out of the 62 ω-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 ω-secalin genes have a typical primary structure, which is different from wheat gliadins. There was no cysteine residue in ω-secalin proteins, and the potential celiac disease (CD) toxic epitope (PQQP) was identified to appear frequently in the repetitive domains. The ω-secalin genes from various cereal species shared high homology in their gene sequences. The ω-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 ω-secalin pseudogenes than in ω-secalin ORFs indicate that the pseudogenes may be subject to a reduced selection pressure. Based on the conserved sequences of ω-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.
Triticeae Research Institute, Sichuan Agricultural University, Ya'an, Sichuan, China.
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D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D002446:Celiac Disease / Q000276:immunology; D032461:Chromosomes, Plant / Q000235:genetics*; D002523:Edible Grain / Q000235:genetics*; D000939:Epitopes / Q000276:immunology; D019143:Evolution, Molecular; D017343:Genes, Plant / Q000235:genetics*; D005983:Glutens / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012434:Secale / Q000235:genetics*; D014178:Translocation, Genetic; D014908:Triticum / Q000235:genetics*
D000939:Epitopes; D005983:Glutens