Journal of Applied Genetics 51(4), 2010, pp. 403-411
Characterization of ω-secalin genes from rye, triticale,
and a wheat 1BL/1RS translocation line
Q-T. Jiang, Y-M. Wei, L. Andre, Z-X. Lu, Z-E. Pu, Y-Y. Peng, Y-L. Zheng
Abstract: 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 &omega-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 ?-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.
Key words: 1BL/1RS translocation, grain quality, Secale cereale, storage proteins, Triticum aestivum, × Triticosecale, ω-secalin.
Correspondence: Y-L. Zheng, Triticeae Research Institute, Sichuan Agricultural University, Ya’an, Sichuan, 625014, China; e-mail: firstname.lastname@example.org
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