State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China.
Department of Plant Biology, College of Biological Sciences, University of California, Davis, Davis, United States.
Elife. 2024 Oct 14;13:RP95891. doi: 10.7554/eLife.95891.
Root-synthesized secondary metabolites are critical quality-conferring compounds of foods, plant-derived medicines, and beverages. However, information at a single-cell level on root-specific secondary metabolism remains largely unexplored. L-Theanine, an important quality component of tea, is primarily synthesized in roots, from which it is then transported to new shoots of tea plant. In this study, we present a single-cell RNA sequencing (scRNA-seq)-derived map for the tea plant root, which enabled cell-type-specific analysis of glutamate and ethylamine (two precursors of theanine biosynthesis) metabolism, and theanine biosynthesis, storage, and transport. Our findings support a model in which the theanine biosynthesis pathway occurs via multicellular compartmentation and does not require high co-expression levels of transcription factors and their target genes within the same cell cluster. This study provides novel insights into theanine metabolism and regulation, at the single-cell level, and offers an example for studying root-specific secondary metabolism in other plant systems.
根合成的次生代谢物是食品、植物药和饮料的关键质量决定化合物。然而，在单细胞水平上，关于根特异性次生代谢的信息在很大程度上仍未得到探索。茶氨酸是茶叶的重要品质成分，主要在根部合成，然后从根部运输到茶树的新梢。在这项研究中，我们提供了一个茶树根的单细胞 RNA 测序 (scRNA-seq) 衍生图谱，使我们能够对谷氨酸和乙胺（茶氨酸生物合成的两个前体）代谢以及茶氨酸的生物合成、储存和运输进行细胞类型特异性分析。我们的研究结果支持了一个模型，即在茶氨酸生物合成途径中发生了细胞间区室化，并且不需要在同一细胞簇中具有高转录因子及其靶基因的共表达水平。这项研究为茶氨酸代谢和调控提供了新的见解，在单细胞水平上，并为在其他植物系统中研究根特异性次生代谢提供了一个范例。
