Comparative Transcriptome Analysis Of Saponin Biosynthesis In Ginseng Cells By MeJA Elicitation

Ginsenoside is one of the triterpenoid saponins in Panax ginseng root,which has extensive pharmarcological effects. However, little is knownabout the molecular mechanisms in the ginsenoside biosynthesis process.Studies have shown that MeJA is a chemical elicitor, which is able toimprove the ginsenoside production. In this experiment, we collectedginseng from Changbai Mountain, Jilin Province, and used it as the explantmaterial. Ginseng callus cultures have been successfully induced and stablysubcultured from one generation to another, and are maintained in amodified MS medium. Ginseng suspension cell cultures have also beensuccessfully established, and the propagation curve shows that ginsengsuspension cell biomass reaches its lag phase from 1st day to 3rd day; itreaches logarithmic phase from the 4th day to the 21st day, with themaximum value on the 21st day, then it reaches the plateau phase. Inaddition, we use MeJA to treat ginseng suspension cells, with aconcentration of 200μmol/L, at 0 h, 24 h, 48 h. It has been verified byRT-PCR that gene transcriptional level of DDS and SE changes in atime-dependent manner, respectively. It reaches its maximum afterelicitation of 24 hours. It also shows that P value is less than 5%, indicatingthat it is statistically acceptable. By using the comparative transcriptomestrategy, and the genetic information of model plant Arabidopsis thaliana,we have found that there are 72 differentially expressed genes, 46 of whichare up-regulated, 26 of which are down-regulated. Cytochrome P450, whichis supposed to be involved in hydroxylation, is upregulated.Semi-quantitative RT-PCR further confirmed that gene expression level ofcytochrome P450 is higher in MeJA group than in control group. Conclusion: In this experiment, ginseng callus has been successfullyinduced and the ginseng suspension cell cultures have been successfullyestablished. By using Arabidopsis expression profiling gene microarray, ithas been found that 46 genes are up-regulated, 26 genes are down-regulated,which provides experimental basis for characterizing and cloning genes thatare related to the ginsenoside biosynthesis.