Transcriptome Level Reveals the Triterpenoid Saponin Biosynthesis Pathway of Bupleurum falcatum L

Genes (Basel). 2022 Nov 29;13(12):2237. doi: 10.3390/genes13122237.

Abstract

Bupleurum falcatum L. is frequently used in traditional herbal medicine in Asia. Saikosaponins (SSs) are the main bioactive ingredients of B. falcatum, but the biosynthetic pathway of SSs is unclear, and the biosynthesis of species-specific phytometabolites is little known. Here we resolved the transcriptome profiles of B. falcatum to identify candidate genes that might be involved in the biosynthesis of SSs. By isoform sequencing (Iso-Seq) analyses of the whole plant, a total of 26.98 Gb of nucleotides were obtained and 124,188 unigenes were identified, and 81,594 unigenes were successfully annotated. A total of 1033 unigenes of 20 families related to the mevalonate (MVA) pathway and methylerythritol phosphate (MEP) pathway of the SS biosynthetic pathway were identified. The WGCNA (weighted gene co-expression network analysis) of these unigenes revealed that only the co-expression module of MEmagenta, which contained 343 unigenes, was highly correlated with the biosynthesis of SSs. Comparing differentially expressed gene analysis and the WGCNA indicated that 130 out of 343 genes of the MEmagenta module exhibited differential expression levels, and genes with the most "hubness" within this module were predicted. Manipulation of these genes might improve the biosynthesis of SSs.

Keywords: Bupleurum falcatum; WGCNA; gene expression; saikosaponin biosynthetic pathway; transcriptome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bupleurum / metabolism
  • Saponins* / analysis
  • Saponins* / biosynthesis
  • Transcriptome
  • Triterpenes* / analysis
  • Triterpenes* / metabolism

Substances

  • saikosaponin D
  • Saponins
  • Triterpenes

Supplementary concepts

  • Bupleurum falcatum

Grants and funding

This work was supported by the earmarked fund for CARS (CARS-21), the CAMS Innovation Fund for Medical Sciences (CIFMS) under grant number 2021-I2M-1-032, the Programs of Science and Technology Department of Sichuan Province (2019YFN0150, 2022NSFSC1639, 2022NSFSC1703), the Doctoral Research Funding of Southwest University of Science and Technology (19zx7117 and 21zx7116), and the Opening Project Fund of Key Laboratory of Rubber Biology and Genetic Resource Utilization, Ministry of Agriculture (RRL-KLOF202201).