Most alpha‐gliadin genes of the Gli‐D2 locus on the D genome of hexaploid bread wheat (Triticum aestivum) encode for proteins with epitopes that can trigger coeliac disease (CD), and several contain a 33‐mer peptide with six partly overlapping copies of three epitopes, which is regarded as a remarkably potent T‐cell stimulator. To increase genetic diversity in the D genome, synthetic hexaploid wheat lines are being made by hybridising accessions of Triticum turgidum (AB genome) and Aegilops tauschii (the progenitor of the D genome). The diversity of alpha‐gliadins in A. tauschii has not been studied extensively. We analysed the alpha‐gliadin transcriptome of 51 A. tauschii accessions representative of the diversity in A. tauschii. We extracted RNA from developing seeds and performed 454 amplicon sequencing of the first part of the alpha‐gliadin genes. The expression profile of allelic variants of the alpha‐gliadins was different between accessions, and also between accessions of the Western and Eastern clades of A. tauschii. Generally, both clades expressed many allelic variants not found in bread wheat. In contrast to earlier studies, we detected the 33‐mer peptide in some A. tauschii accessions, indicating that it was introduced along with the D genome into bread wheat. In these accessions, transcripts with the 33‐mer peptide were present at lower frequencies than in bread wheat varieties. In most A. tauschii accessions, however, the alpha‐gliadins do not contain the epitope, and this may be exploited, through synthetic hexaploid wheats, to breed bread wheat varieties with fewer or no coeliac disease epitopes.

中文翻译：

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探索 α-麦醇溶蛋白基因座：小麦中具有六个重叠乳糜泻表位的 33-mer 肽来自 Aegilops tauschii 的一个亚群

六倍体面包小麦 ( Triticum aestivum ) D 基因组上Gli-D2基因座的大多数 α-麦醇溶蛋白基因编码具有可引发乳糜泻 (CD) 的表位的蛋白质，并且一些包含具有六个部分重叠拷贝的 33 聚体肽三个表位，被认为是一种非常有效的 T 细胞刺激剂。为了增加 D 基因组的遗传多样性，正在通过杂交小麦（AB 基因组）和Aegilops tauschii（D 基因组的祖先）的种质来制备合成六倍体小麦品系。A. tauschii中 α-醇溶蛋白的多样性尚未得到广泛研究。我们分析了 51 A. tauschii的 α-醇溶蛋白转录组代表A. tauschii多样性的种质。我们从发育中的种子中提取 RNA，并对 α-麦醇溶蛋白基因的第一部分进行了 454 个扩增子测序。α-麦醇溶蛋白等位基因变体的表达谱在种质之间以及在A. tauschii的西方和东方进化枝的种质之间是不同的。一般来说，两个进化枝都表达了许多在面包小麦中没有发现的等位基因变体。与早期的研究相反，我们在一些A. tauschii种质中检测到 33-mer 肽，表明它与 D 基因组一起被引入面包小麦中。在这些种质中，具有 33 聚体肽的转录本的出现频率低于面包小麦品种。在大多数A. tauschii 然而，α-麦醇溶蛋白不包含表位，可以通过合成六倍体小麦利用这一点来培育具有较少或没有乳糜泻表位的面包小麦品种。