Main conclusionComparative proteomics and metabolomics study of juvenile green, light purple and dark purple leaf to identify key proteins and metabolites that putatively govern color transition in Camellia sinensis.AbstractColor transition from juvenile green to dark purple leaf in Camellia sinensis is a complex process and thought to be regulated by an intricate balance of genes, proteins and metabolites expression. A molecular-level understanding of proteins and metabolites expression is needed to define metabolic process underpinning color transition in C. sinensis. Here, purple leaf growth of C. sinensis cultivar was divided into three developmental stages viz. juvenile green (JG), light purple (LP) and dark purple (DP) leaf. Scanning electron microscope (SEM) analysis revealed a clear morphological variation such as cell size, shape and texture as tea leaf undergoing color transition. Proteomic and metabolomic analyses displayed the temporal changes in proteins and metabolites that occur in color transition process. In total, 211 differentially expressed proteins (DEPs) were identified presumably involved in secondary metabolic processes particularly, flavonoids/anthocyanin biosynthesis, phytohormone regulation, carbon and nitrogen assimilation and photosynthesis, among others. Subcellular localization of three candidate proteins was further evaluated by their transient expression in planta. Interactome study revealed that proteins involved in primary metabolism, precursor metabolite, photosynthesis, phytohormones, transcription factor and anthocyanin biosynthesis were found to be interact directly or indirectly and thus, regulate color transition from JG to DP leaf. The present study not only corroborated earlier findings but also identified novel proteins and metabolites that putatively govern color transition in C. sinensis. These findings provide a platform for future studies that may be utilized for metabolic engineering/molecular breeding in an effort to develop more desirable traits.

中文翻译：

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紫茶（Camellia sinensis）颜色转变的调控

主要结论 通过比较蛋白质组学和代谢组学研究青、浅紫色和深紫色的幼叶，以确定假定控制茶树颜色转变的关键蛋白质和代谢物。受基因、蛋白质和代谢物表达的复杂平衡调节。需要在分子水平上了解蛋白质和代谢物的表达，以定义支撑中华冬青颜色转变的代谢过程。在这里，C. sinensis 品种的紫叶生长分为三个发育阶段，即。幼年绿 (JG)、浅紫色 (LP) 和深紫色 (DP) 叶。扫描电子显微镜 (SEM) 分析揭示了明显的形态变化，例如细胞大小、茶叶的形状和质地正在经历颜色的转变。蛋白质组学和代谢组学分析显示了颜色转换过程中发生的蛋白质和代谢物的时间变化。总共鉴定出 211 种差异表达蛋白 (DEP) 可能参与次级代谢过程，特别是类黄酮/花青素生物合成、植物激素调节、碳和氮同化以及光合作用等。通过它们在植物中的瞬时表达进一步评估了三种候选蛋白质的亚细胞定位。Interactome 研究表明，参与初级代谢、前体代谢物、光合作用、植物激素、转录因子和花青素生物合成的蛋白质被发现直接或间接相互作用，从而调节从 JG 到 DP 叶的颜色转变。本研究不仅证实了早期的发现，而且还确定了新的蛋白质和代谢物，这些蛋白质和代谢物假定控制了中华红豆的颜色转变。这些发现为未来的研究提供了一个平台，可用于代谢工程/分子育种，以开发更理想的性状。