Woo-Saeng Kwon

Ginsenoside profiles and related gene expression during foliation in Panax ginseng Meyer

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.

A PCR-based SNP marker for specific authentication of Korean ginseng ( panax ginseng ) cultivar “Chunpoong”

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.

Investigation of ginsenosides in different tissues after elicitor treatment in Panax ginseng

Background The 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. Methods Different 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. Results The 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. Conclusion These 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.

Molecular authentication of Panax ginseng and ginseng products using robust SNP markers in ribosomal external transcribed spacer region

Panax ginseng and Panax quinquefolius are the most widely used Panax species, but they are known to have different properties and medicinal values. The aim of this study is to develop a robust and accurate DNA marker for identifying P. ginseng and the origins of ginseng products. Two single nucleotide polymorphism (SNP) sites specific to P. ginseng were exploited from nuclear ribosomal external transcribed spacer (ETS) region. Based on the SNP sites, two specific primers were designed for P. ginseng and P. quinquefolius respectively. P. ginseng can be easily discriminated from P. quinquefolius by amplifying the two specific alleles using multiplex allele-specific PCR. Favorable results can also be obtained from commercial ginseng products. The established method is highly sensitive and can detect 1% of intentional adulteration of P. quinquefolius into P. ginseng down to the 0.1ng level of total DNA. Therefore this study provides a reliable and simple DNA method for authentication of the origins and purities of ginseng products.

Molecular identification of the Korean ginseng cultivar “Chunpoong” using the mitochondrial nad7 intron 4 region

Background and aims. Korean ginseng (Panax ginseng) is one of the most important medicinal plants in the Orient. Among the nine cultivars of Korean ginseng, “Chunpoong” commands a much greater market value and has been planted widely. Materials and methods. A rapid and reliable method for discriminating the Chunpoong cultivar was developed by exploiting a single nucleotide polymorphism (SNP) in the mitochondrial nad7 intron 4 region of nine Korean ginseng cultivars using universal primers. Results. A SNP was detected between Chunpoong and other cultivars, and modified allele-specific primers were designed from this SNP site to specifically identify Chunpoong cultivar via multiplex PCR. Conclusion. We therefore present an effective method for the genetic identification of the Chunpoong cultivar of ginseng.

Molecular characterization of two glutathione peroxidase genes of Panax ginseng and their expression analysis against environmental stresses

Glutathione 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 (H2O2) 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 681bp with a deduced amino acid sequence of 240 and 226 residues, respectively. The calculated molecular mass of the matured proteins are approximately 26.4kDa or 25.7kDa 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.

A simple and rapid technique for the authentication of the ginseng cultivar, Yunpoong, using an SNP marker in a large sample of ginseng leaves

Yunpoong is an important Korean ginseng (Panax ginseng C. A. Meyer) cultivar, but no molecular marker has been available to identify Yunpoong from other cultivars. In this study, we developed a single nucleotide polymorphism (SNP) marker for Yunpoong based on analysis of expressed sequence tags (ESTs) in an exon region of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene. This SNP marker had high specificity to authenticate Yunpoong in twelve different main ginseng cultivars. For application of the molecular marker, a rapid identification method was established based on the NaOH-Tris method and real-time polymerase chain reaction (PCR) in order to ensure more efficiency in the cultivar selection. The biggest feature of the NaOH-Tris method was that it made the extraction of DNA very simple and rapid in young leaf tissues. We only spent 1 min to extract DNA and directly used it to do PCR. In this report, the conventional DNA extraction method was used to develop molecular marker process, and the NaOH-Tris method was applied in screening large numbers of cultivars. Moreover, the greatest advantage of the real-time PCR compared with traditional PCR, is time saving and high efficiency. Thus, this strategy provides a rapid and reliable method for the specific identification of Yunpoong in a large number of samples.

Molecular characterization of 5-chlorophyll a/b -binding protein genes from Panax ginseng Meyer and their expression analysis during abiotic stresses

The chlorophyll a/b-binding protein (CAB) serves in both photosystems (PS), I and II, as a coordinator of antenna pigments in the light-harvesting complex (LHC). The CABs constitute abundant and important proteins in the thylakoid membrane of higher plants. In our study, five CAB genes, which contained full-length cDNA sequences from the 4-year-old ginseng leaves (Panax ginseng Meyer), were isolated and named PgCAB. Phylogenetic comparison of the members of the subfamily between ginseng and higher plants, including Arabidopsis, revealed that the putative functions of these ginseng CAB proteins were clustered into the different family of Arabidopsis CABs; two PgCABs in LHCII family and three PgCABs in LHCI family. The expression analysis of PgCABs consistently showed dark-dependent inhibition in leaves. Expression analysis during abiotic stress identified that PgCAB genes responded to heavy metal, salinity, chilling, and UV stresses differently, suggesting their specific function during photosynthesis. This is the first comprehensive study of the CAB gene family in P. ginseng.

Characteristics of Korean ginseng varieties of Gumpoong, Sunun, Sunpoong, Sunone, Cheongsun, and Sunhyang

Background Ginseng (Panax ginseng Meyer) is an important medicinal herbs in Asia. However, ginseng varieties are less developed. Method To developed ginseng varieties, a pure line selection method was applied in this study. Results Gumpoong was testing of 4-yr-old specimens in 2002, the proportions of the below-ground roots that were rusty colored for Gumpoong was 1.29 in Daejeon and 1.45 in Eumseong, whereas the proportions for its yellow berry variant were 2.60 and 2.45 in the two regions, respectively. Thus the Gumpoong was resistant to root rust. Sunpoong has a high yielding property. Its average root weight is 70.6 g for 6-yr-old roots. Its yield is 2.9 kg/1.62m2 and the rate of heaven- and earth-grade product is 20.9%, which is very high compared to 9.4% for Yunpoong. Sunone is resistance to root rot and the survival rate of 4-yr-old roots was 44.4% in 1997, whereas that of the violet-stem variant landrace was 21.7%. Sunhyang has content of arginyl-fructosyl-glucose (AFG), which produces the unique scent of red ginseng, is 95.1 μmol/g and greater than the 30.8 μmol/g of Chunpoong in 6-yr-old plants. Sunun and Cheongsun are being nurtured to protect genetic resources. Conclusion Developed ginsneg varieties will be used as the basis for the protection of genetic resources and breeding.

Cloning and characterization of pathogenesis-related protein 4 gene from Panax ginseng

The family of pathogenesis-related protein 4 (PR4) is a group of proteins with a Barwin domain in C-terminus and generally thought to be involved in plant defense responses. In the present study, PR4 (designated as PgPR4) cDNA was isolated from the leaf of Panax ginseng C.A. Meyer. and characterized. The ORF is 513 bp with a deduced amino acid sequence of 170 residues. A GenBank BlastX search revealed that the deduced amino acid of PgPR4 shares the highest sequence similarity to PR4 of Sambucus nigra (72% identity). Sequence and structural analysis indicated that PgPR4 belongs to class II of PR4 proteins. This is the first report on the isolation of PR4 gene from the P. ginseng genome. The high-level expression of PgPR4 was observed in the root as revealed by quantitative real-time PCR. The temporal expression analysis demonstrated that PgPR4 expression could be up-regulated by pathogen infection, salt, wounding, and hormone stresses. These results suggest that PgPR4 could play a role in the molecular defense response of ginseng to abiotic stress and pathogen attack.