Effects of Different Culture Times Genes Expression on Ginsenoside Biosynthesis of the Ginseng Adventitious Roots in Panax ginseng

Abstract

Panax ginseng is an ancient and very potent herb, which has a long history of medicinal use, and recent studies have shown that ginsenosides are the main active substances in its pharmacological effects. However, the saponin content of wild ginseng and cultivated ginseng can hardly meet the market supply, and the ginseng adventitious root suspension culture technology can produce ginsenosides in a targeted manner. The length of culture time is an important factor affecting the growth and development of plants and the accumulation of secondary metabolites. After transcriptome sequencing of ginseng adventitious root material at different culture times, the results showed that a total of 5784 differentially expressed genes were screened, which contained 239 transcription factors. KEGG analysis showed that these differentially expressed genes were mainly enriched in metabolic pathways and biosynthesis of secondary metabolites. A proposed temporal analysis of differentially expressed genes among the two groups distributed the differentially expressed genes under nine clusters, and the differentially expressed genes under different clusters had the same expression trends, indicating that these genes can be jointly involved in specific biological processes. Extraction of ginsenosides from ginseng adventitious roots using water-saturated n-butanol and detection of ginsenoside content by high-performance liquid chromatography revealed a significant increase in total saponins and protopanaxadiol ginsenosides (particularly significant for ginsenosides Rd and Rb1), an increase in bioaccumulation of some protopanaxatriol ginsenosides, and a decrease in some protopanaxatriol ginsenosides (S-Rh1, R-Rg3, and Rf) saponin content decreased. We also found seven genes involved in ginsenoside biosynthesis and that the changes in these genes’ expression may be related to the accumulation of ginsenosides.