Qi Peng-Fei, Chen Qing, Ouellet Thérèse, Wang Zhao, Le Cheng-Xing, Wei Yu-Ming, Lan Xiu-Jin, Zheng You-Liang
Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, 611130, Sichuan, China.
Genetica. 2013 Sep;141(7-9):303-10. doi: 10.1007/s10709-013-9729-2. Epub 2013 Jul 27.
Many of the unique properties of wheat flour are derived from seed storage proteins such as the α-gliadins. In this study these α-gliadin genes from diploid Triticeae species were systemically characterized, and divided into 3 classes according to the distinct organization of their protein domains. Our analyses indicated that these α-gliadins varied in the number of cysteine residues they contained. Most of the α-gliadin genes were grouped according to their genomic origins within the phylogenetic tree. As expected, sequence alignments suggested that the repetitive domain and the two polyglutamine regions were responsible for length variations of α-gliadins as were the insertion/deletion of structural domains within the three different classes (I, II, and III) of α-gliadins. A screening of celiac disease toxic epitopes indicated that the α-gliadins of the class II, derived from the Ns genome, contain no epitope, and that some other genomes contain much fewer epitopes than the A, S(B) and D genomes of wheat. Our results suggest that the observed genetic differences in α-gliadins of Triticeae might indicate their use as a fertile ground for the breeding of less CD-toxic wheat varieties.
小麦粉的许多独特特性源自种子贮藏蛋白，如α-醇溶蛋白。在本研究中，对来自二倍体小麦族物种的这些α-醇溶蛋白基因进行了系统表征，并根据其蛋白质结构域的不同组织方式分为3类。我们的分析表明，这些α-醇溶蛋白所含半胱氨酸残基的数量各不相同。大多数α-醇溶蛋白基因在系统发育树中根据其基因组起源进行分组。正如预期的那样，序列比对表明，重复结构域和两个聚谷氨酰胺区域是导致α-醇溶蛋白长度变化的原因，α-醇溶蛋白的三个不同类别（I、II和III）内结构域的插入/缺失也是如此。对乳糜泻毒性表位的筛选表明，源自Ns基因组的II类α-醇溶蛋白不含表位，而且其他一些基因组所含表位比小麦的A、S(B)和D基因组少得多。我们的结果表明，在小麦族α-醇溶蛋白中观察到的遗传差异可能表明它们可作为培育低乳糜泻毒性小麦品种的沃土。
