Triterpene saponins (ginsenosides) are main bioactive compounds in Panax ginseng. From mevalonic acid pathway, the isoprene units was synthesized that is precusor of triterpene saponin. This study provides the complete nucleotide sequence of the full-length cDNA involved in mevalonic acid biosynthesis pathway. We had a full-length cDNA sequences as followed; HMGS (1944bp, 1407bp ORF), HMGR (2120bp,1728bp ORF) and MDD (1760bp, 1263bp ORF) with partial poly (A). We were used real time PCR and High Performance Liquid Chromatography (HPLC) to analysis the expression level of the gene involved in MVA pathway and to ginsenoside contents, respectively. All cloned genes are constitutively expressed in all tested tissues but at different levels with the highest expression in fine roots. But ginsenoside contents is highest in leaf > fine root> lateral root > red berry> main root > petiol > stem. After treantment of methyl Jasmonate (MeJA), MVA pathway genes are highly expressed and ginsenoside contents was high at 72h.

Methyl jasmonate(MeJA) treatment promotes the plant secondary, especially triterpene saponin which is main compounds in Platycodon grandiflorum. We were performed 5,760 expressed sequence tags from MeJA treated hairy root. Total number of ESTs are 2,536 (811 contigs and 1,725 singletons) among them 2,299 are pass the annotation. The most abundant transcript were encoding fatty acid desaturase (FAD) and lots of secondary metabolite transcript were observed. Four MVA pathway genes (HMGS, HMGR, MK, MDD) and one MEP pathway gene (IDI) are identified. The unigene were classified into three major functional categories by standard GO (Gene Ontology) - cellular component, molecular function and biological process. In this study we were cloned four genes from ESTs : HMGS (1401bp ORF), MK (1167bp ORF), MDD (1254bp ORF), IDI (909bp ORF)