Wheat kernel proteins are not homogeneously distributed throughout the endosperm. The goal of this study was to investigate the relative differences in protein composition between the aleurone, sub-aleurone and inner endosperm. Using laser microdissection followed by nanoLC-MS/MS, an innovative method combining high spatial specificity and analytical selectivity in sample-limited situations, 780 proteins were detected and classified by function. A higher proportion of gluten proteins was detected in the sub-aleurone than inner endosperm. Composition-wise, gluten from the sub-aleurone is relatively more enriched in ω-gliadins but impoverished in LMW-GS and γ-gliadins. While a basic set of albumins and globulins was detected in all three microdissected endosperm tissues, specific proteins, like puroindoline B, displayed a gradient. This study provides indications that both histological origin and relative positioning of the tissues drive the protein distribution. Knowledge of this protein distribution offers significant opportunities for the wheat manufacturing industry. Data available via ProteomeXchange, identifier PXD038743.

小麦籽粒蛋白在整个胚乳中分布不均匀。本研究的目的是研究糊粉层、亚糊粉层和内胚乳之间蛋白质组成的相对差异。使用激光显微切割和 nanoLC-MS/MS（一种在样品有限的情况下结合了高空间特异性和分析选择性的创新方法），检测到了 780 种蛋白质并按功能进行了分类。在糊粉层下检测到的麸质蛋白比例高于内胚乳。从成分角度来看，来自亚糊粉层的面筋相对富含 ω-麦醇溶蛋白，但 LMW-GS 和 γ-麦醇溶蛋白较少。虽然在所有三种显微解剖的胚乳组织中都检测到了一组基本的白蛋白和球蛋白，但特定的蛋白质（如嘌呤吲哚啉 B）却显示出梯度。这项研究表明组织的组织学起源和相对位置驱动蛋白质分布。了解这种蛋白质分布为小麦制造业提供了重大机遇。数据可通过 ProteomeXchange 获取，标识符 PXD038743。