• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.16-22
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• 2005

cDNA for oxidosqualene cyclase was cloned by a homology-based PCR method and sequenced from Centella asiatica. In a sequences analysis, the putative polypeptide of C. asiatica cycloartenol synthase (CaCYS) deduced from the 2,274 bp nucleotide sequence, consisted of 758 amino acids and had a molecular mass of 86.3 kD. The predicted amino acid sequence exhibited high homology to that of PNX (cycloartenol synthase) from Panax ginseng ($89\%$). Southern blot analysis suggests that CaCYS may be present in one copy of the C. asiatica genome. If methyl jasmonate (MJ) is applied exogenously to plants, not only triterpene saponins are accumulated in tissues, but also it produces effects such as growth inhibition and the promotion of ethylene production. In order to investigate the effect of MJ and thidiazuron (TDZ), a cytokinin that plays a role as an antisenescence agent in several plants, on the level of CaCYS mRNA, we performed northern blot analysis. When MJ is alone treated by adding to culture medium, CaCYS transcripts were inhibited. However, sustained levels of the expression of CaCYS, by adding TDZ to the medium despite MJ treatments, were demonstrated in C. asiatica leaves.

• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.91-94
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• 2005

Plants have been known to accumulate a very diverse range of triterpene saponins. We have investigated the regulation of saponin biosynthesis in higher plants using Centella asiatica (L.) Urban as a model plant. Effects of a feeding precursor on asiaticoside production from leaves and on the level of two-type OSCs mRNA were investigated. As a feeding precursor, squalene negatively affected the levels of CYS and bAS mRNA, but it also decreased the production of asiaticoside from whole plants. Plant hormones regulate secondary metabolism, and in plant tissue cultures they could affect both culture growth and secondary metabolite production. Although enhancement of asiaticoside production from whole plant cultures by addition of TDZ (thidiazuron) has been reported, the positive effect of TDZ on the levels of OSCs transcripts was not observed.

• Journal of Ginseng Research
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• v.33 no.3
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• pp.206-211
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• 2009

In order to investigate the effects of elicitors on the growth and ginsenoside biosynthesis of ginseng hairy roots, we treated Panax ginseng hairy root with various concentrations of Haliotidis concha according to different time course. Haliotidis concha supplement increased the biomass and ginsenoside accumulation at 10 mg/L concentration. The growth rate of hairy root under a lighter concentration was greater than hairy root treated with a denser concentration. The highest content and productivity of ginsenosides appeared at 2 weeks after the treatment of 10 mg/L Haliotidis concha. The gene expression of squalene synthase, squalene epoxidase, dammarenediol synthase, cycloartenol synthase, $\beta$-amyrin synthase in hairy roots of ginseng were examined by RT-PCR. The Haliotidis concha treatment resulted in the obvious accumulation of the mRNA of triterpene biosynthesis in Panax ginseng hairy root as compared with the control. In this study, Haliotidis concha acts as a kind of elicitor for the production of ginsenosides.

• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.233-236
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• 2005

Centella asiatica accumulates large amounts of triterpene saponin, such as centellasaponin, asiaticoside, madecassoside. We examined the effect of two candidates, MJ (Methyl jasmonate) and TDZ (thidiazuron), on asiaticoside production and the accumulation of bAS mRNA associated with asiaticoside biosynthesis in leaves of cultured whole plants. The growth of whole plants treated with 0.1 mM MJ was found to decrease significantly, however, the growth of whole plants treated with 0.1 mM MJ plus 0.025 mg/l TDZ was better than that treated with MJ alone. When MJ alone was added to culture medium, asiaticoside contents in leaves were higher than that of control after 7 days of treatments. The maximum level of bAS $({\beta}-amyrin\;synthsae)$ mRNA in leaves of whole plant treated TDZ and MJ was transiently observed after exposure to 5 days. These results showed the up-regulation of bAS gene by adding TDZ and MJ at the molecular level, however, synergic effects of TDZ and MJ on asiaticoside biosynthesis were not testified.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.72.2-73
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• 2003

We found a soybean (Glycine max) cultivar 561 that was strongly resistant to a virulent bacterial strain of a Pseudomonas spp. Further identification revealed that the Pseudomonas spp. was a strain of Pseudomonas aeruginosa. Furthermore we identified specific genes involved in the resistance of soybean 561 and analyzed the pattern of gene expression against the Pseudomonas infection using differential-display reverse transcription PCR (DDRT-PCR). More than 126 cDNA fragments representing mRNAs were induced within 48 hours of bacteria inoculation. Among them, 28 cDNA fragments were cloned and sequenced. Twelve differentially displayed clones with open reading frames had unknown functions. Sixteen selected cDNA clones were homologous to known genes in the other organisms. Some of the identified cDNAs were pathogenesis-related genes (PR genes) and PR-like genes. These cDNAs included a putative calmodulin-binding protein, an endo-1,3-1,4-b-D-glucanase, a b-1,3-endoglucanase, a b-1,3-exoglucanase, a phytochelatin synthetase-like gene, a thiol pretense, a cycloartenol synthase, and a putative receptor-like sorineithreonine protein kinase. Among them, we found that four genes were putative pathogenesis-related genes (PR) induced significantly by the p. aeruginosa infection. These included a calmodulin-binding protein gene, a b-1,3-endoglucanase gene, a receptor-like sorine/threonine protein kinase gene, and pS321 (unknown function). These results suggest that the differentially expressed genes may mediate the strong resistance of soybean 561 to Pseudomonas aeruoginosa.

• The Plant Pathology Journal
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• v.19 no.5
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• pp.239-247
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• 2003

In Korea, a local soybean (Glycine max) genotype 56l. was found to be strongly resistant to a virulent bacterial strain of a Pseudomonas sp. SN239. Specific genes involved in the resistance of the soybean genotype 561 were identified and the pattern of gene expression against the Pseudomonas infection was analyzed using differential-display reverse transcription PCR (DDRT-PCR). More than 126 cDNA fragments representing mRNAs were induced within 48 hours of bacteria inoculation. Among them, 28 cDNA fragments were cloned and sequenced. Twelve differentially displayed clones with open reading frames had unknown functions. Sixteen selected cDNA clones were homologous to known genes of other organisms. Some of the identified cDNAs were pathogenesis-related (PR) genes and PR-like genes. These cDNAs included a putative calmodulin-binding protein; an endo-l,3-1,4-$\bate$-D-glucanase; a $\bate$-1,3-endoglucanase; a $\bate$-1,3-exoglucanase; a phytochelatin synthetase-like gene; a thiol protease; a cycloartenol synthase; and a putative receptor-like serine/threonine protein kinase. Among them, four genes were found to be putative PR genes induced significantly by the Pseudomonas infection. These included a calmodulin-binding protein gene, a $\bate$-1,3-endoglucanase gene, a receptor-like serine/threonine protein kinase gene, and pS321 (unknown function). These results suggest that the differentially expressed genes may mediate the strong resistance of soybean 561 to the strain SN239 of Pseudomonas sp.

• Journal of Ginseng Research
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• v.46 no.2
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• pp.225-234
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• 2022

Background: Ginseng, officially known as Panax ginseng Meyer, has been traditionally used as a medicinal herb, particularly in Asia. Ginseng is propagated from seeds; however, seed germination is challenging, especially in its natural environment on farms. The seeds typically exhibit morphophysiological dormancy and require release from both morphological and physiological dormancy before germination. Although some studies have proposed methods for increasing seed germination rates, the underlying mechanisms of its dormancy release process remain unclear. Here, we investigated metabolic alterations during dehiscence in P. ginseng to determine their potential roles in dormancy release. Methods: We compared the ginseng seed metabolome before and after dehiscence and the ginsenoside and phytosterol compositions of the seeds in both periods in the presence of related enzymes. Results: After seed dehiscence, the sugar, amino acid, and squalene concentrations were significantly altered, phytosterols associated with the stigmasterol biosynthesis pathway were increased, while ginsenoside and brassinosteroid levels were not significantly altered. In addition, squalene epoxidase, cycloartenol synthase, 24-methylenesterol C-methyltransferase, and the stigmasterol biosynthesis pathway were activated. Conclusion: Overall, our findings suggest that morphological activities that facilitate ginseng seed growth are the primary phenomena occurring during the dehiscence process. This study improves the understanding of P. ginseng germination processes and promotes further research of its germination and cultivation.

• Journal of Ginseng Research
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• v.38 no.4
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• pp.270-277
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• 2014

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.