Hullessbarley (Hordeum vulgare L.) is a barley cultivar, serving as one of the major food crops worldwide. The main nutrients in hulless barley are starch, protein, and β-glucan, the contents of which vary considerably among different cultivars. However, the potential molecular mechanisms that underlie these variations in nutrient are still insufficiently clear. In this study, the nutrient content of two hulless barley cultivars (‘Zangqing 2000’ and ‘C2’) was analyzed, and quantitative tandem mass tag-LC-MS/MS proteomics and bioinformatics analysis were used to verify the differentially expressed proteins (DEPs) between the two cultivars. Parallel reaction monitoring (PRM) analysis was used to verify the expression change of candidate DEPs. The content of starch and amylose in C2 was lower than that in Zangqing 2000, and β-glucan, protein content, and amylopectin showed a higher concentration in C2 hulless barley cultivar. A total of 326 DEPs were identified, with 108 induced proteins and 218 reduced proteins in C2 compared with Zangqing 2000. Further functional and pathways analysis of DEPs revealed that C2 hulless barley cultivar has relatively more biological activities, and DEPs in C2 hulless barley cultivar were mainly associated with the biological processes of multiple important metabolic pathways. Moreover, PRM analysis showed the accuracy level of quantitative proteomic data. Overall, this was the first study that undertook the proteomic analysis in Zangqing 2000 and C2 and the results revealed the molecular mechanisms of seed nutrient biosynthesis and accumulation, which provide key insights about the development of hulless barley quality.

中文翻译：

---

基于蛋白质组学的两个无壳大麦品种谷物营养成分的比较分析

Hullessbarley（大麦）L.) 是一种大麦品种，是世界上主要的粮食作物之一。去壳大麦的主要营养成分是淀粉、蛋白质和β-葡聚糖，其含量因品种而异。然而，这些营养变化背后的潜在分子机制仍然不够清楚。本研究对两个无壳大麦品种（'藏青2000'和'C2'）的营养成分进行了分析，并利用定量串联质量标签-LC-MS/MS蛋白质组学和生物信息学分析验证了差异表达蛋白（DEPs） ) 两个品种之间。平行反应监测 (PRM) 分析用于验证候选 DEP 的表达变化。C2中淀粉和直链淀粉含量低于藏青2000，β-葡聚糖、蛋白质、支链淀粉在 C2 无壳大麦品种中显示出更高的浓度。与藏青2000相比，共鉴定出326个DEPs，其中C2诱导蛋白108个，还原蛋白218个。 DEPs的进一步功能和通路分析表明，C2无壳大麦品种的生物活性相对较高，C2无壳大麦品种的DEPs主要与多种重要代谢途径的生物过程有关。此外，PRM 分析显示了定量蛋白质组学数据的准确性水平。总体而言，这是在藏青 2000 和 C2 中进行蛋白质组学分析的第一项研究，结果揭示了种子养分生物合成和积累的分子机制，为无壳大麦品质的发展提供了关键见解。