College of Biological and Chemical Engineering, Anhui Polytechnic University, Wuhu, Anhui 241000, China.
Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Department of Agronomy, Zhejiang University, Hangzhou 310058, China.
J Agric Food Chem. 2021 Jan 13;69(1):568-583. doi: 10.1021/acs.jafc.0c05284. Epub 2020 Dec 28.
The hull-less barley (Qingke) is widely planted as a staple food crop in the Tibetan area, China, and the grains contains high content of β-glucan (BG). The mechanisms of BG synthesis and accumulation in qingke has not been studied at the protein level. This study characterized the proteins associated with BG synthesis and accumulation during qingke seed development. The proteome profiles of qingke seeds taken at 20, 30, and 40 days after flowering were compared using the TMT-based quantitative proteomics. A total of 4283 proteins were identified, with 759 being differentially expressed (DEPs) throughout seed development. Comparisons of protein expression pattern, functions, and pathway enrichment tests highlight cell wall modification, carbon and energy metabolism, polysaccharide metabolism, post-transcriptional modifications, and vesicular transport as critical biological processes related to qingke BG accumulation. Furthermore, induction of starch synthase, starch branching enzyme, pectin acetyl esterases, beta-glucosidases, beta-amylases, 1,4-beta-xylan, xyloglucan, α-amylase inhibitors, and glycosyltransferases underpinned BG synthesis. The results also indicated that the proteins involved in glycolytic, gluconeogenesis, and glyoxylate bypass pathways provided energy and reducing power for BG storage. Parallel reaction monitoring (PRM) and quantitative real-time PCR (qPCR) analyses confirmed the expression profile of the proteins obtained by TMT-based proteomics. The current results provided an insight into the mechanisms of BG synthesis and accumulation during qingke seed development.
青稞（裸大麦）是中国西藏地区广泛种植的主食作物，其籽粒含有丰富的β-葡聚糖（BG）。但青稞中 BG 的合成和积累机制尚未在蛋白质水平上进行研究。本研究旨在分析青稞种子发育过程中与 BG 合成和积累相关的蛋白质。采用基于 TMT 的定量蛋白质组学技术比较了开花后 20、30 和 40 天的青稞种子的蛋白质组图谱。共鉴定到 4283 种蛋白质，其中 759 种在种子发育过程中差异表达（DEPs）。蛋白质表达模式、功能和通路富集测试的比较突出了细胞壁修饰、碳和能量代谢、多糖代谢、转录后修饰和囊泡运输等与青稞 BG 积累相关的关键生物学过程。此外，淀粉合酶、淀粉分支酶、果胶乙酰酯酶、β-葡萄糖苷酶、β-淀粉酶、1,4-β-木聚糖、木葡聚糖、α-淀粉酶抑制剂和糖基转移酶的诱导支持 BG 的合成。研究结果还表明，糖酵解、糖异生和乙醛酸旁路途径中涉及的蛋白质为 BG 储存提供了能量和还原力。平行反应监测（PRM）和定量实时 PCR（qPCR）分析证实了 TMT 蛋白质组学分析得到的蛋白质表达谱。本研究结果为深入了解青稞种子发育过程中 BG 的合成和积累机制提供了参考。
