Transcriptome and metabolome analysis revealed the changes of Geniposide and Crocin content in Gardenia jasminoides fruit

Background Gardenia jasminoides Ellis is a perennial evergreen shrub of G. jasminoides of Rubiaceae. Geniposide and Crocin are important components in the fruit of G. jasminoides. In addition to being used as medicinal materials, they are also widely used in food, medicine, cosmetics, and other fields. They have high medicinal value, economic value, and ornamental value. However, at present, the utilization rate of G. jasminoides resources is low, mainly focused on germplasm cultivation,primary processing, and clinical pharmacology, and there are few studies on the quality of Gardenia fruit.Methods and results Based on transcriptome sequencing and metabolic group analysis, the morphological and structural changes of Gardenia fruit with young fruit, middle fruit, and ripe fruit were analyzed, and the formation mechanism and content changes of Geniposide and Crocin in Gardenia fruit were studied. The content of Geniposide decreased with the development of fruit, so did the expression of the main structural gene GES, G10H, and IS in its synthesis pathway, while the content of Crocin increased with the development of fruit, and the expression of the main structural gene CCD, ALDH, and UGT in its synthesis pathway also increased. The relationship between the morphological structure of G. jasminoides and the accumulation of Geniposide and Crocin was summarized. Conclusions This study not only provides a theoretical basis for the mining and utilization of Geniposide and Crocin, but also provides a theoretical basis for genetic background for the identification and cloning of bioactive substances in gardenia fruit in future. At the same time, it provides support for increasing the dual-use value of G. jasminoides and breeding excellent germplasm resources.

背景：栀子（Gardenia jasminoides Ellis）为茜草科栀子属多年生常绿灌木。京尼平苷（Geniposide）与番红花素（Crocin）是栀子果实中的核心活性成分，除药用外，还被广泛应用于食品、医药、化妆品等诸多领域，兼具极高的药用价值、经济价值与观赏价值。但当前栀子资源利用率偏低，现有研究多集中于种质培育、初级加工及临床药理学方向，针对栀子果实品质的相关研究较为匮乏。
方法与结果：本研究依托转录组测序（transcriptome sequencing）与代谢组学分析（metabolomic analysis），系统分析了幼果、中果与成熟果三个发育阶段栀子果实的形态结构变化，并探究了栀子果实中京尼平苷与番红花素的形成机制及含量动态变化规律。结果显示，京尼平苷含量随果实发育进程逐步降低，其生物合成通路中的关键结构基因GES、G10H与IS的表达水平也同步下调；而番红花素含量随果实发育逐渐升高，其合成通路中的关键结构基因CCD、ALDH与UGT的表达量同样呈上升趋势。本研究还总结了栀子形态结构与京尼平苷、番红花素积累之间的内在关联。
结论：本研究不仅为京尼平苷与番红花素的挖掘与产业化利用提供了坚实的理论基础，也为未来栀子果实中生物活性物质的鉴定与克隆提供了遗传背景层面的理论支撑，同时对提升栀子的综合利用价值以及优良种质资源的选育具有重要指导意义。