Gluten-free foods cannot substitute for products made from wheat flour. When wheat products are digested, the remaining peptides can trigger an autoimmune disease in 1% of the North American and European population, called coeliac disease. Because wheat proteins are encoded by a large gene family, it has been impossible to use conventional breeding to select wheat varieties that are coeliac-safe. However, one can test the properties of protein variants by expressing single genes in coeliac-safe cereals like maize. One source of protein that can be considered as coeliac-safe and has bread-making properties is teff (Eragrostis tef), a grain consumed in Ethiopia. Here, we show that teff α-globulin3 (Etglo3) forms storage vacuoles in maize that are morphologically similar to those of wheat. Using transmission electron microscopy, immunogold labelling shows that Etglo3 is almost exclusively deposited in the storage vacuole as electron-dense aggregates. Of maize seed storage proteins, 27-kDa γ-zein is co-deposited with Etglo3. Etglo3 polymerizes via intermolecular disulphide bonds in maize, similar to wheat HMW glutenins under non-reducing conditions. Crossing maize Etglo3 transgenic lines with α-, β- and γ-zein RNA interference (RNAi) lines reveals that Etglo3 accumulation is only dramatically reduced in γ-zein RNAi background. This suggests that Etglo3 and 27-kDa γ-zein together cause storage vacuole formation and behave similar to the interactions of glutenins and gliadins in wheat. Therefore, expression of teff α-globulins in maize presents a major step in the development of a coeliac-safe grain with bread-making properties.

中文翻译：

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迈向腹腔安全的面包。

无麸质食品不能替代小麦粉制成的产品。消化小麦产品时，剩余的肽可引发1％的北美和欧洲人口自身免疫疾病，称为乳糜泻。由于小麦蛋白是由一个大的基因家族编码的，因此不可能使用常规育种选择具有腹腔安全的小麦品种。但是，可以通过在玉米等腹腔安全的谷物中表达单个基因来测试蛋白质变异体的特性。可以被认为是腹腔安全的，具有面包制作特性的蛋白质之一，是埃塞俄比亚食用的谷物teff（Eragrostis tef）。在这里，我们表明，teffα-globulin3（Etglo3）在玉米中形成与小麦相似的贮藏液泡。使用透射电子显微镜 免疫金标记显示Etglo3几乎全部以电子致密聚集体的形式沉积在储存液泡中。在玉米种子贮藏蛋白中，27-kDaγ-玉米醇溶蛋白与Etglo3共沉积。Etglo3通过玉米中的分子间二硫键聚合，类似于在非还原条件下的小麦HMW谷蛋白。将玉米Etglo3转基因品系与α-，β-和γ-玉米醇溶蛋白RNA干扰（RNAi）杂交，表明Etglo3积累仅在γ-玉米醇溶蛋白RNAi背景下显着减少。这表明，Etglo3和27-kDaγ-玉米醇溶蛋白一起引起储存液泡的形成，其行为类似于小麦中谷蛋白和麦醇溶蛋白的相互作用。因此，在玉米中表达teffα-球蛋白代表了具有面包制作特性的腹腔安全谷物的发展的重要一步。