Production of ginsenoside by Chaetomium sp. and its effect on enhancing the contents of ginsenosides in Panax ginseng adventitious roots

Using endophytic fungi elicitors to enhance the yield of valuable secondary metabolites in plant tissue culture is an effective biotechnology strategy. In this study, we isolated an endophytic fungus Chaetomium sp. from cultivated Panax ginseng root and detected a high concentration of Rg(3) in its mycelium. By comparing the effects of different treatments of Chaetomium sp. on ginsenoside production in Panax ginseng adventitious roots (PGARs), the immobilized spores of Chaetomium sp. (ISC) were proved to be the best elicitor. An initial pH of 6.5 and cocultivation time of 24 h yielded the highest ginsenosides content (56.29 +/- 0.62 mg/g) in ISC-treated PGARs, increasing ginsenosides production by 3.2-fold compared with the blank group (17.56 +/- 0.49 mg/g). Moreover, we show that ISC could stimulate the temporary accumulation of defense-related signal molecules, intensify the expression of defense genes in PGARs, and upregulate biosynthetic genes involved in the biosynthetic pathway of ginsenosides. Besides, the expression of the biosynthetic gene FPS (farnesyl diphosphate synthase) was deemed the most relevant factor for ginsenosides production during the elicitation period, and the L-aspartic acid secreted by Chaetomium sp. was proven to play a key role in the elicitation process. In conclusion, this study provides an accessible way of improving pharmacologically active compounds production in medicinal plants.

Automated summary

The use of endophytic fungi elicitors to enhance the production of valuable secondary metabolites in plant tissue culture is an effective biotechnology strategy. The isolated Chaetomium sp. was found to contain a high concentration of Rg(3) in its mycelium, with the immobilized spores of Chaetomium sp. shown to be the best elicitor for increasing ginsenoside production in Panax ginseng adventitious roots. ISC treatment not only led to increased ginsenosides content, but also stimulated the accumulation of defense-related signal molecules, intensified the expression of defense genes, and upregulated biosynthetic genes involved in the biosynthetic pathway of ginsenosides.