## 3 Discussion
ginseng__FPS_ within 12 h of treatment, achieving its maximum value after 24 h. In consequence, the increased activity of farnesyl diphosphate synthase was observed between 12 h and 7 days of methyl jasmonate elicitation [41]. Moreover, transgenic lines of _P. ginseng_ root, obtained from the adventitious root by inserting the _P. ginseng FPS_ gene that regulated the activity of farnesyl diphosphate synthase, showed an 11.1-fold higher level of the transcriptions of that gene and a 2.4-fold increase in the ginseng content in comparison with the control [26]. Figure 8: Scheme of the ginseng biosynthetic pathway in ginseng according to [PERSON] et al. [42]. ACT—acetyl-CoA acetyltransferasease; CAS—cycloartenol synthase; CDP-ME—4-cytidine diphosphate-2-C-methyl-D-erythitol; CDP-ME2P—-CDP-ME-2-phosphate; CMK—CDP-ME kinase;  
DDS--dammarenediol synthase; DMAPP--dimethylallyl pyrophosphate; DXP--1-deoxy-D-xylulose-5-phosphate; DXR--reducoisomerase; DXS--DXP synthetase; FPP--farnesyl diphosphate; FPS--farnesyl diphenylphosphate synthase; GAP--glyceraldehydehyde-3-phosphate; GTS--glycosyltransferase; HDR--HMBPP reductase; HDS--HMBPP synthetase; HMBPP--(E)-4-hydroxy-3-methylbut-2-enyl diphosphate; HMG-CoA--3-hydroxy-3-methylglutural-CoA; HMGR--HMG-CoA reductase (3-hydroxy-3-methylglutural-CoA reductase; HMGS--HMG-CoA synthase; IDI--isopentenyl diphosphate isomerase; IPP--isopentenyl diphosphate; LAS--lanosterol synthase; MCT--4-cytidine diphosphate-2-C-methyl-D-erythhitol synthetase; MDS--2-C-methyl-D-erythhitol-2,4-cyclic phosphate synthetase; MEP--2-C-methyl-D-erythhitol 4-phosphate; MVA--mevalonic acid; MVD--mevalonate diphosphate decarboxylase; MVK--mevalonate kinase; MVP--mevalonate phosphate; MVPP--mevalonate diphosphate; OAS--oleanolic acid synthase (CYP716A52); PMK--phosphomewalonate kinase; PPDS--protonanaxadiol synthase (CYP716A7); PPDS--protonanaxadiol synthase (CYP716A7); SPE--protonanaxatriol synthase (CYP716A53); SE--squalene epoxidase; SS--squalene synthase; \(\beta\)-AS--\(\beta\)-amyrin synthase. The results of this paper confirmed that the expression of the \(SS\) gene was also up-regulated after carvacrol treatment, reaching its maximum 12-fold increase in comparison to the control. This observation confirmed that carvacrol exhibits a weaker effect on the \(SS\) gene than on the _farnesyl pyrophosphate synthase_ gene. The _squalene synthase_ gene codes squalene synthase (SS), which carries out the reaction leading to squalene formation by condensing two molecules of farnesyl diphosphate. Squalene is considered a precursor of 2,3-oxidosqualene and dammarenediol [40]. The important role of the stimulation of \(SS\) gene expression, in order to ensure effective ginseng production with the use of the elicitation process, was demonstrated in many previous reports [18; 27; 43; 44]. The response of the hairy root of _P. quinqueifolium_ was extremely strong and manifested with the up-regulation of the _squalene synthase_ gene (a 2435.4-fold increase in expression in comparison to the control) after MJ elicitation. In consequence, the production of saponin was significantly enhanced [30]. The influence of methyl jasmonate on \(SS\) gene expression was also tested in root cultures of _P. ginseng_[27], and it was observed that the up-regulation of the \(SS\) gene increased the expression of downstream genes, such as the _squalene epoxidase_ gene (_SE_). Furthermore, the increased production of ginseng's belonging to dammaranatype metabolites was noticed. This information implied that the \(SS\) gene can take part in the regulation of a further stage of the ginseng saponin biosynthetic pathway. Moreover, some data demonstrated a significant improvement of the expression of _Panax ginseng_ genes, such as _HMGR, gemanyl diphosphate synthase (GPS), FPS, SS,_ and _SE_, after fungal elicitor treatment, which resulted in the enhanced production of ginseng saponins [45]. Dammarenediol is formed as a result of squalene transformation to 2,3-oxidosqualene. Next, 2,3-oxidosqualene is cyclized to a tetracyclic dammarenediol backbone.