Abstract：
In order to better understand the mechanism of betaine accumulation in Lycium barbarum L. (LBL), we used iTRAQ (Isotope relative and absolute quantitative labeling) proteomics to screen and identify differentially abundant proteins (DAPs) at five stages (S1-young fruit stage, S2-green fruit stage, S3-early yellowing stage, S4-late yellowing stage, S5-ripening stage). A total of 1799 DAPs and 171 betaine-related DAPs were identified, and phosphatidylethanolamine N-methyltransferase (NMT), choline monooxygenase (CMO), and betaine aldehyde dehydrogenase (BADH) were found to be the key enzymes related to betaine metabolism. These proteins are mainly involved in carbohydrates, amino acids and their derivatives, fatty acids, carboxylic acids, photosynthesis and photoprotection, isoquinoline alkaloid biosynthesis, peroxisomes, and glycine, serine, and threonine metabolism. Three of the key enzymes were also up- and down-regulated to different degrees at the mRNA level. The study provide new insights into the of mechanism of betaine accumulation in LBL. SIGNIFICANCE: Betaine, a class of naturally occurring, water-soluble alkaloids, has been found to be widespread in animals, higher plants, and microbes. In addition to being an osmotic agent, betaine has biological functions such as hepatoprotection, neuroprotection, and antioxidant activity. Betaine metabolism (synthesis and catabolism) is complexly regulated by developmental and environmental signals throughout the life cycle of plant fruit maturation. As a betaine-accumulating plant, little has been reported about the regulatory mechanisms of betaine metabolism during the growth and development of Lycium barbarum L. (LBL) fruit. Therefore, this study used iTRAQ quantitative proteomics technology to investigate the abundance changes of betaine-related proteins in LBL fruit, screen and analyze the differential abundance proteins related to betaine metabolism, and provide theoretical references for the in-depth study of the mechanism of betaine metabolism in LBL fruit.
摘要：
为了更好地了解枸杞甜菜碱积累的机理,我们使用iTRAQ（同位素相对和绝对定量标记）蛋白质组学在五个阶段（S1-幼果期，S2-绿色水果阶段，S3-早期黄变阶段，S4-晚黄变阶段，S5-成熟阶段)。总共确定了1799个DEP和171个与甜菜碱相关的DEP，和磷脂酰乙醇胺N-甲基转移酶（NMT），胆碱单加氧酶（CMO），发现甜菜碱醛脱氢酶（BADH）是与甜菜碱代谢相关的关键酶。这些蛋白质主要参与碳水化合物，氨基酸及其衍生物，脂肪酸，羧酸，光合作用和光保护，异喹啉生物碱生物合成，过氧化物酶体,和甘氨酸,丝氨酸,苏氨酸代谢.三种关键酶在mRNA水平上也有不同程度的上调和下调。该研究为甜菜碱在LBL中积累的机制提供了新的见解。意义:甜菜碱,一类自然发生的，水溶性生物碱，已经发现在动物中普遍存在，高等植物,和微生物。除了是渗透剂，甜菜碱具有保肝等生物学功能,神经保护,和抗氧化活性。甜菜碱代谢（合成和分解代谢）在植物果实成熟的整个生命周期中受到发育和环境信号的复杂调节。作为一种积累甜菜碱的植物，关于枸杞（LBL）果实生长发育过程中甜菜碱代谢的调节机制的报道很少。因此,本研究利用iTRAQ定量蛋白质组学技术研究甜菜碱相关蛋白在LBL果实中的差异变化,筛选并分析与甜菜碱代谢相关的差异表达蛋白，为深入研究LBL果实甜菜碱代谢机制提供理论参考。
