• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.217-223
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• 2005

Effects of growth regulators on growth of adventitious roots and accumulation of steroidal saponins, such as dioscin, prosapogenin A and prosapogenin C, in cultures of Dioscorea nipponica were determined. The maximum growth of adventitious roots was observed in MS medium supplemented with 30 g/L sucrose and 1.0 mg/L NAA. Addition of BA in combination with NAA appeared to be no effective in the growth of adventitious roots. Among the twenty different adventitious roots formed from different seeds, strain No. 10 was selected based on production ability of dioscin, and its stability through the successive liquid culture. During the first 4 weeks of incubation, contents of steroidal saponins in adventitious roots were negligible but the contents were markedly increased at 5 weeks of incubation. Dioscin and prosapogenin C content in IBA-treated adventitious roots were significantly higher than those in NAA-treated roots. However, content of prosapogenin A was not significantly different among NAA or IBA level. Results provide that liquid culture of adventitious roots of D. nipponica have a potential for mass production of dioscin including prosapogenin A and prosapogenin C.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.47-53
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• 2007

This study was carried out to identify the treatment methods for the inhibition of lateral roots and promotion of hypocotyl enlargement using plant growth regulators for the production of high quality soybean sprouts. Inhibition of lateral root formation was not significant from the $CA_3$ and NAA treatments. From the treatment of BAP, lateral roots were not occurred at all, and hypocotyl enlargement was promoted at the low concentration of $10\;mg{\cdot}L^{-1}\;and\;15\;mg{\cdot}L^{-1}$. Promotion of hypocotyl enlargement was higher as the BAP treatment time was shorter. The optimum time of BAP treatment was 6 hours. Occurrence ratio of lateral roots were low and hypocotyl enlargement was promoted from water supply every 24 hours after BAP treatment. In the indole B treatment, lateral roots occurrence was very low with the concentration of 1.1%, which is much lower than the optimum concentration of 4.2%.

• Korean Journal of Plant Tissue Culture
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• v.21 no.2
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• pp.123-129
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• 1994

The potency of adventitious root initiation was investigated in relation with germination days and ike end of culture days healed with root induction medium on the initiation of adventitious roots from explants of soybean (Glycine max L.) cotyledon. Also, the changes in the pattern of protein profiles related with adventitious mot initiation have been examined by two-dimensional polyauyl-amide gel elecoophoresis during the germination and the initiation of adventitious roots. The potency of adventitious root initiation from germinated cotyledons was high after 4 days, and adventitious roots were initiated from after 4 days and very high after 6 days healed with mot induction medium There was a reproducible quantitative change in 34 specific protein spots during germination and adventitious root initiation. A necessary basic protein for adventitious root initiation with rotative molecular weight of 27 kD was induced during the germination. And three basic protein groups with relative molecular weight 22 kD, 23 kD and 33 kD, and two acidic protein groups with relative molecular weight 27kD and 29 kD were induced during the initiation of adventitious roots.

• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.507-514
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• 1998

The effects of media and elicitors on betalain, phytolaccoside G and D2 production were examined in the hairy roots of Phytolacca esculenta van Houtte induced by Agrobacterium tumefaciens $A_4$T. Phytolaccoside G and D2 from Phytolacca hairy roots PEH2 were identified by TLC, HPLC, IR, Mass, $^1$H-NMR, and ^(13)C-NMR. Among the culture media tested, SH medium was the best for hairy root growth of hairy roots. White medium was the most suitable medium for betalain production, while MS medium was for phytolaccoside G and D2 production. Although the growth of hairy roots was supped by light (1,000 Lux), the production of betalain, phytolaccoside G and D2 was enhanced by the same light treatment. Addition of elicitors such as NaF, chitosan, and yeast extract to the culture medium increased the content of betalain, phytolaccoside G and D2, suggesting the importance of culture condition for the production of those componds.

• Korean Journal of Plant Tissue Culture
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• v.22 no.6
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• pp.345-350
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• 1995

Root gravitropism was investigated in the pea (Pisum sativum L.) mutant ageotropum lacking normal gravitropic response. Exogenous ethylene treatment inhibited gravitropic response in the normal (wild type) pea rook, but had no significant effect to restore the unresponsiveness in the mutant Neither inhibitors of ethylene biosynthesis nor antagonists of ethylene action were able to bring about the development of gravioopic curvature in the ageotropum roots. Auxin action seems to be normal since asymmetric application of agar blocks containing auxin to the mutant roots caused normal gravitropic response to occur. Endogenous as well as auxin-induced ethylene production in tissue segments of the mutant root was about equal to that of the wild type. However no appreciable lateral transport of labeled auxin was observed in glavistimulated mutant roots whereas typical auxin asymetry was apparent in the wild type roots under the same conditions. It is concluded that the mutant has a defect in either gravity perception or its transduction, but not in the effector system involving auxin action.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.65-71
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• 2003

This research aims the production of anti-tumor substances through in vitro culture of hairy roots transformed by Agrobacterium rhizogenes in Artemisia sylvatica MAX and the effect of culture conditions on optimum growth of hairy roots. We investigated the optimum medium, pH, carbon source, sucrose, light, Fe and polyamine conditions of various lines of hairy roots (NK3, NK4, YX. NK3-10) induced from Artemisia sylvatica to increase the optimum growth of hairy roots. MS medium was the best for optimum growth of hairy root clone, NK3-S10. The optimum culture period was 4 weeks for NK3-S10. The optimum sucrose concentration was 3.5%. The optimum concentration of FeSO$_4$, spermine and spermidine was 0.1 mM, 10 mM and 100 mM, respectively.

• Journal of Ginseng Research
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• v.47 no.3
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• pp.469-478
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• 2023

Background: Nitrogen (N) is an essential macronutrient for plant growth and development. To support agricultural production and enhance crop yield, two major N sources, nitrate and ammonium, are applied as fertilizers to the soil. Although many studies have been conducted on N uptake and signal transduction, the molecular genetic mechanisms of N-mediated physiological roles, such as the secondary growth of storage roots, remain largely unknown. Methods: One-year-old P. ginseng seedlings treated with KNO₃ were analyzed for the secondary growth of storage roots. The histological paraffin sections were subjected to bright and polarized light microscopic analysis. Genome-wide RNA-seq and network analysis were carried out to dissect the molecular mechanism of nitrate-mediated promotion of ginseng storage root thickening. Results: Here, we report the positive effects of nitrate on storage root secondary growth in Panax ginseng. Exogenous nitrate supply to ginseng seedlings significantly increased the root secondary growth. Histological analysis indicated that the enhancement of root secondary growth could be attributed to the increase in cambium stem cell activity and the subsequent differentiation of cambium-derived storage parenchymal cells. RNA-seq and gene set enrichment analysis (GSEA) revealed that the formation of a transcriptional network comprising auxin, brassinosteroid (BR)-, ethylene-, and jasmonic acid (JA)-related genes mainly contributed to the secondary growth of ginseng storage roots. In addition, increased proliferation of cambium stem cells by a N-rich source inhibited the accumulation of starch granules in storage parenchymal cells. Conclusion: Thus, through the integration of bioinformatic and histological tissue analyses, we demonstrate that nitrate assimilation and signaling pathways are integrated into key biological processes that promote the secondary growth of P. ginseng storage roots.

• Journal of Life Science
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• v.29 no.11
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• pp.1281-1293
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• 2019

The rhizosphere is the active zone where plant roots communicate with the soil microbiome, each responding to the other's signals. The soil microbiome within the rhizosphere that is beneficial to plant growth and productivity is known as plant growth-promoting rhizobacteria (PGPR). PGPR take part in many pivotal plant processes, including plant growth, development, immunity, and productivity, by influencing acquisition and utilization of nutrient molecules, regulation of phytohormone biosynthesis, signaling, and response, and resistance to biotic- and abiotic-stresses. PGPR also produce secondary compounds and volatile organic compounds (VOCs) that elicit plant growth. Moreover, plant roots exude attractants that cause PGPR to aggregate in the rhizosphere zone for colonization, improving soil properties and protecting plants against pathogenic factors. The interactions between PGPR and plant roots in rhizosphere are essential and interdependent. Many studies have reported that PGPR function in multiple ways under the same or diverse conditions, directly and indirectly. This review focuses on the roles and strategies of PGPR in enhancing nutrient acquisition by nutrient fixation/solubilization/mineralization, inducing plant growth regulators/phytohormones, and promoting growth and development of root and shoot by affecting cell division, elongation, and differentiation. We also summarize the current knowledge of the effects of PGPR and the soil microbiota on plants.

• Journal of Ginseng Research
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• v.44 no.3
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• pp.405-412
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• 2020

Background: Root rot is a serious destructive disease of Panax notoginseng, a famous cultivated araliaceous herb called Sanqi or Tianqi in Southwest China. Methods: The chemical substances of Sanqi rot roots were explored by chromatographic techniques. MS, 1D/2D-NMR, and single crystal X-ray diffraction were applied to determine the structures. Murine macrophage RAW264.7 and five human cancer cell lines were used separately for evaluating the antiinflammatory and cytotoxic activities. Results and Conclusion: Thirty dammarane-type triterpenes and saponins were isolated from the rot roots of P. notoginseng. Among them, seven triterpenes, namely, 20(S)-dammar-25-ene-24(S)-hydroperoxyl-3β,6α,12β,20-tetrol (1), 20(S)-dammar-3-oxo-23-ene-25-hydroperoxyl-6α,12β,20-triol (2), 20(S)-dammar-12-oxo-23-ene-25-hydroperoxyl-3β,6α,20-triol (3), 20(S)-dammar-3-oxo-23-ene-25-hydroperoxyl-12β,20-diol (4), 20(S),24(R)-epoxy-3,4-seco-dammar-25-hydroxy-12-one-3-oic acid (5), 20(S),24(R)-epoxy-3,4-seco-dammar-25-hydroxy-12-one-3-oic acid methyl ester (6), and 6α-hydroxy-22,23,24,25,26,27-hexanordammar-3,12,20-trione (7), are new compounds. In addition, 12 known ones (12-16 and 19-25) were reported in Sanqi for the first time. The new Compound 1 showed comparable antiinflammatory activity on inhibition of NO production to the positive control, whereas the known compounds 9, 12, 13, and 16 displayed moderate cytotoxicities against five human cancer cell lines. The results will provide scientific basis for understanding the chemical constituents of Sanqi rot roots and new candidates for searching antiinflammatory and antitumor agents.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.881-891
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• 2003

Paenibacillus polymyxa is a plant growth-promoting rhizobacterium (PGPR) which can be used for biological control of plant diseases. Several bacterial strains were isolated from rotten roots of Korean ginseng (Panax ginseng C. A. Meyer) that were in storage. These strains were identified as P. polymyxa, based on a RAPD analysis using a P. polymyxa-specific primer, cultural and physiological characteristics, an analysis utilizing the Biolog system, gas chromatography of fatty acid methyl esters (GC-FAME), and the 16S rDNA sequence analysis. These strains were found to cause the rot in stored ginseng roots. Twenty-six P. polymyxa strains, including twenty GBR strains, were phylogenetically classified into two groups according to the ERIC and BOX-PCR analyses and 16S rDNA sequencing, and the resulting groupings systematized to the degrees of virulence of each strain in causing root rot. In particular, highly virulent GBR strains clustered together, and this group may be considered as subspecies or biovar. The virulence of the strains seemed to be related to their starch hydrolysis enzyme activity, but not their cellulase or hemicellulase activity, since strains with reduced or no starch-hydrolytic activity showed little or no virulence. Artificial inoculation of the highly virulent strain GBR-1 onto the root surfaces of Korean ginseng resulted in small brown lesions which were sunken and confined to the outer portion of the root. Ginseng root discs inoculated in vitro or two-year-old roots grown in soil drenched with the inoculum developed significant rot only when the inoculum density was $10^{6}-10^{7}$ or more colony-forming units (CFU) per ml. These results suggest that P. polymyxa might induce ginseng root rot if their population levels are high. Based on these results, it is recommended that the concentration of P. polymyxa should be monitored, when it is used as a biocontrol agent of ginseng, especially in the treatment of stored roots.