Germination is a critical process in the reproduction and propagation of flowering plants, and is also the key stage of industrial grain malting. Germination commences when seeds are steeped in water, followed by degradation of the endosperm cell walls, enzymatic digestion of starch and proteins to provide nutrients for the growing plant, and emergence of the radicle from the seed. Dormancy is a state where seeds fail to germinate upon steeping, but which prevents inappropriate premature germination of the seeds before harvest from the field. This can result in inefficiencies in industrial malting. We used Sequential Window Acquisition of all THeoretical ions Mass Spectrometry (SWATH-MS) proteomics to measure changes in the barley seed proteome throughout germination. We found a large number of proteins involved in desiccation tolerance and germination inhibition rapidly decreased in abundance after imbibition. This was followed by a decrease in proteins involved in lipid, protein and nutrient reservoir storage, consistent with induction and activation of systems for nutrient mobilisation to provide nutrients to the growing embryo. Dormant seeds that failed to germinate showed substantial biochemical activity distinct from that of seeds undergoing germination, with differences in sulfur metabolic enzymes, endogenous alpha-amylase/trypsin inhibitors, and histone proteins. We verified our findings with analysis of germinating barley seeds from two commercial malting facilities, demonstrating that key features of the dynamic proteome of germinating barley seeds were conserved between laboratory and industrial scales. The results provide a more detailed understanding of the changes in the barley proteome during germination and give possible target proteins for testing or to inform selective breeding to enhance germination or control dormancy.

中文翻译：

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蛋白质组学揭示了对大麦种子发芽的承诺，其特点是应激反应蛋白的丢失和营养物质库的动员

发芽是开花植物繁殖和繁殖的关键过程，也是工业谷物制麦的关键阶段。当种子浸入水中后开始发芽，随后胚乳细胞壁降解，淀粉和蛋白质的酶消化为生长中的植物提供营养，并从种子中出现胚根。休眠状态是种子浸泡后无法发芽的状态，但可以防止从田间收获之前种子过早发芽。这可能导致工业制麦芽效率低下。我们使用所有理论离子质谱（SWATH-MS）蛋白质组学的顺序窗口采集来测量整个发芽过程中大麦种子蛋白质组的变化。我们发现，大量蛋白质参与了干燥后的耐旱性和萌发抑制作用，吸收后其丰度迅速降低。其次是参与脂质，蛋白质和养分储库的蛋白质减少，这与诱导和激活养分动员系统以向正在生长的胚胎提供养分的系统一致。未发芽的休眠种子显示出与正在发芽的种子不同的重要生化活性，其中硫代谢酶，内源性α-淀粉酶/胰蛋白酶抑制剂和组蛋白均存在差异。我们通过分析两个商业制麦厂发芽的大麦种子，验证了我们的发现，证明了发芽的大麦种子动态蛋白质组的关键特征在实验室和工业规模之间得到了保留。结果提供了对大麦蛋白质组在发芽过程中变化的更详细的了解，并提供了可能的靶蛋白进行测试或告知选择性育种以增强发芽或控制休眠。