Panax ginseng is one of the most important medicinal plants in Asia. Triterpene saponins, known as ginsenosides, are the major pharmacological compounds in P. ginseng. The present study was conducted to evaluate the changes in ginsenoside composition according to the foliation stage of P. ginseng cultured in a hydroponic system. Among the three tested growth stages (closed, intermediate, and opened), the highest amount of total ginsenoside in the main and fine roots was in the intermediate stage. In the leaves, the highest amount of total ginsenoside was in the opened stage. The total ginsenoside content of the ginseng leaf was markedly increased in the transition from the closed to intermediate stage, and increased more slowly from the intermediate to opened leaf stage, suggesting active biosynthesis of ginsenosides in the leaf. Conversely, the total ginsenoside content of the main and fine roots decreased from the intermediate to opened leaf stage. This suggests movement of ginsenosides during foliation from the root to the leaf, or vice versa. The difference in the composition of ginsenosides between the leaf and root in each stage of foliation suggests that the ginsenoside profile is affected by foliation stage, and this profile differs in each organ of the plant. These results suggest that protopanaxadiol- and protopanaxatriol (PPT)-type ginsenosides are produced according to growth stage to meet different needs in the growth and defense of ginseng. The higher content of PPT-type ginsenosides in leaves could be related to the positive correlation between light and PPT-type ginsenosides.

BackgroundThe effect of methyl jasmonate (MJ) on ginsenoside production in different organs of ginseng (Panax ginseng Meyer) was evaluated after the whole plant was dipped in an MJ-containing solution. MJ can induce the production of antioxidant defense genes and secondary metabolites in plants. In ginseng, MJ treatment in adventitious root resulted in the increase of dammarenediol synthase expression but a decrease of cycloartenol synthase expression, thereby enhancing ginsenoside biosynthesis. Although a previous study focused on the application of MJ to affect ginsenoside production in adventitious roots, we conducted our research on entire plants by evaluating the effect of exogenous MJ on ginsenoside production with the aim of obtaining new approaches to study ginsenoside biosynthesis response to MJ in vivo.MethodsDifferent parts of MJ-treated ginseng plants were analyzed for ginsenoside contents (fine root, root body, epidermis, rhizome, stem, and leaf) by high-performance liquid chromatography.ResultsThe total ginsenoside content of the ginseng root significantly increased after 2 d of MJ treatment compared with the control not subjected to MJ. Our results revealed that MJ treatment enhances ginsenoside production not in the epidermis but in the stele of the ginseng root, implying transportation of ginsenosides from the root vasculature to the epidermis. Application of MJ enhanced protopanaxadiol (PPD)-type ginsenosides, whereas chilling treatment induced protopanaxatriol (PPT)-type ginsenosides.ConclusionThese findings indicate that the production of PPD-type and PPT-type ginsenosides is differently affected by abiotic and biotic stresses in the ginseng plant, and they might play different defense mechanism roles.

a b s t r a c t a r t i c l e i n f oGlutathione peroxidases (GPXs) are a group of enzymes that protect cells against oxidative damage generated by reactive oxygen species (ROS). GPX catalyzes the reduction of hydrogen peroxide (H 2 O 2 ) or organic hydroperoxides to water or alcohols by reduced glutathione. The presence of GPXs in plants has been reported by several groups, but the roles of individual members of this family in a single plant species have not been studied. Two GPX cDNAs were isolated and characterized from the embryogenic callus of Panax ginseng. The two cDNAs had an open reading frame (ORF) of 723 and 681 bp with a deduced amino acid sequence of 240 and 226 residues, respectively. The calculated molecular mass of the matured proteins are approximately 26.4 kDa or 25.7 kDa with a predicated isoelectric point of 9.16 or 6.11, respectively. The two PgGPXs were elevated strongly by salt stress and chilling stress in a ginseng seedling. In addition, the two PgGPXs showed different responses against biotic stress. The positive responses of PgGPX to the environmental stimuli suggested that ginseng GPX may help to protect against environmental stresses.

Korean ginseng (Panax ginseng) has been developed as a horticultural crop due to the increasing demand in the world market. "Chunpoong" is an economically important cultivar with superior quality and high yield among nine cultivars of Korean ginseng. The aim of this work was to develop a simple technique for specific authentication of Chunpoong using DNA method. Molecular authentication of Chunpoong was investigated using DNA sequences of mitochondrial cytochrome oxidase subunit 2 (cox2) intron I and intron II regions. A single nucleotide polymorphism (SNP) specific to Chunpoong was detected and amplification refractory mutation system (ARMS)-PCR method was applied to specific identification of Chunpoong based on the SNP site. Ginseng samples collected from other locations were used to validate the SNP marker and the established method was determined to be effective. Thus, this work provides a rapid and reliable method for the specific identification of Chunpoong cultivar.

Polygalacturonase inhibiting proteins (PGIPs) are the major defense proteins which play an important role in resistance to infection of pathogens. A putative novel gene encoding PGIP was isolated from Panax ginseng C.A. Meyer, which shows 70.3 and 68.4% homology with chick pea and Arabidopsis PGIPs. The RACE PCR was preformed to isolate the full-length PGIP cDNA from Panax ginseng. Sequence analysis revealed that the cDNA of PgPGIP is of 1,275 bp in length and that it's containing ORF encodes for a polypeptide of 366 amino acids. Domain analysis revealed that the deduced amino acid sequences of PgPGIP have a typical PGIP topology. The transcription level of PgPGIP was up-regulated in ginseng in response to wounding and infection with phytopathogenic fungi i.e., Rhizoctonia solani, Fusarium oxysporum, Phythium ultimum, Botrytis cinerea, Colletotrichum gloeosporioides and Cylindrocarpon destructans, which causes drastic damage in ginseng plants. The constitutive PgPGIP expression of 4 years old plant, showed elevated transcript level, especially roots, showed maximum then buds, stems and leaves, indicating that the gene is developmentally regulated. The crude PGIP extracts derived from the fungal infected plants directly reduces the aggressive potential of PGs from diverse group of fungi. Like other PGIPs, PgPGIP also possess board spectrum of inhibitory activity. Thus, the presence of PgPGIP gene and their active role in defense mechanism was proved. The structural model of PgPGIP was predicted based on the alignment generated by EBI-Align, the program "MOODELLER" and the predicted structure showed 10 β-strands and 10 α-helixes region.