Drought Stress Stimulates the Terpenoid Backbone and Triterpenoid Biosynthesis Pathway to Promote the Synthesis of Saikosaponin in Bupleurum chinense DC. Roots

Abstract

Bupleurum chinense is an important medicinal plant in China; however, little is known regarding how this plant transcribes and synthesizes saikosaponins under drought stress. Herein, we investigated how drought stress stimulates the transcriptional changes of B. chinense to synthesize saikosaponins. Short-term drought stress induced the accumulation of saikosaponins, especially from the first re-watering stage (RD_1 stage) to the second re-watering stage (RD_2 stage). Saikosaponin-a and saikosaponin-d increased by 84.60% and 75.13%, respectively, from the RD_1 stage to the RD_2 stage. Drought stress also stimulated a rapid increase in the levels of the hormones abscisic acid, salicylic acid, and jasmonic acid. We screened 49 Unigenes regarding the terpenoid backbone and triterpenoid biosynthesis, of which 33 differential genes were significantly up-regulated during drought stress. Moreover, one P450 and two UGTs are possibly involved in the synthesis of saikosaponins, while some transcription factors may be involved in regulating the expression of key enzyme genes. Our study provides a reference for the cultivation of B. chinense and a practical means to ensure the quality (safety and effectiveness) of B. chinense for medicinal use, as well as insights into the modernization of the China Agriculture Research System.

Comparative metabolic profiling of the mycelium and fermentation broth of Penicillium restrictum from Peucedanum praeruptorum rhizosphere

“…The biosynthesis of the terpenoid skeleton is responsible for the later formation of different terpenoids (Sun & Li, 2018 ). Bupleurum chinense promotes the synthesis of saikosaponin by affecting the terpene skeleton and triterpenoid biosynthesis (Yang et al, 2022 ). More investigation is needed to determine whether P. praeruptorum produces terpenes via rhizosphere fungi, thereby facilitating the production of saponins.…”

Multi-Omics Elucidates Difference in Accumulation of Bioactive Constituents in Licorice (Glycyrrhiza uralensis) under Drought Stress

“…In terms of the triterpenoid saponins, predominant types of licorice derived from glycyrrhizin, the classic oleanane structure, stemming from the mevalonic acid pathway of terpene backbone. Several investigations have suggested that triterpenoid saponins have been conducive to the adaptation of plants in water-deficit conditions [48][49][50]. Currently, the pathway of glycyrrhizin has been completely clarified, obtaining bAS, two key CYP450 enzymes (CYP88D6 and CYP72A154), and two UDPs (GuCSyGT and UGT73P12).…”

Physiological and Transcriptional Analysis Provides Insights into Tea Saponin Biosynthesis and Regulation in Response to SA in Camellia vietnamensis Huang

“…The tea saponin biosynthesis pathway can be divided into initiation, skeleton construction, and modification [9,10]. In the initial stage, isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) are synthesized via mevalonic acid (MVA) and methylerythritol phosphate (MEP) pathways [11].…”

“…The research on the biosynthesis pathway of tea saponin is still in its infancy, and the main task is to mine genomic and transcriptome data. For example, Yang et al [10] identified key genes in the tea saponin biosynthesis pathway, including 143 key genes in the initial and skeleton construction stage and 1169 CYP450 and 1019 UGT in the modification phase, by analyzing the released genome data of C. oleifera [12]. Yang et al [13] cloned 41 WRKY transcription factors through transcriptome sequencing, five of which may regulate SQS genes, and proved that CoWRKY1 could bind to the promoter region of SQS by using yeast monohybrid (Y1H) technology.…”