• KSBB Journal
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• v.8 no.1
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• pp.62-68
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• 1993

Transformed rice plantlet were recovered from protoplasts by electroporation with the plasmld pB 1121, which contain the plant expressible NPT-II and GUS genes. Embryonic cell suspension culture was established with embryonic callus induced from mature seeds of rice (Oryza sativa L. cv. Dong-jin) on the MS medium supplemented with 2.0 mg/l 2,4-D, 0.5 mg/l kinetin, 3% sucrose. Protoplasts isolated from embryonic cell suspensions were electroplated and then poterltialty-transformed tissues were selected by growth on the medium containing 200 mg/l kanamycin sulfate. When subjected to GUS assay, they stained blue, indicating the expression of the inserted GUS genes. Plantlets were regenerated from electroplated protoplasts on the hormone free MS medium. Transferred foreign genes in the plants were confirmed by southern hybridization. These results support use of electroporation for transformation of these important cereal plants.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.187-192
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• 2022

The repeated monthly or weekly subculture of plant callus is labor intensive and increases the risk of somaclonal variation from the parental callus line. The most effective method for preserving plant callus is cryopreservation, which involves storage in liquid nitrogen. However, this method cannot be applied to the callus of different plant species in the same manner, so it is difficult to develop a standardized cryopreservation method. In addition, the survival rate of the frozen callus after thawing and the regeneration rate after survival are uncertain. Therefore, it is necessary to develop a method to extend the subculture interval of plant callus in an active state. In this study, active plant calli of various species without freezing was incubated at 15℃ for 4 to 12 weeks without subculture. After 12 weeks, 8 lines of plant callus grew less than 2-fold when cultured at 25℃, but at least 2 times as much when cultured at 15℃. Moreover, total antioxidant activity did not differ significantly between plant callus recovered at 25℃ after culturing at 15℃ or at 25℃. These results show that the subculture interval can be extended at a temperature of 15℃ without need for modified medium composition or additional processes. In addition, positive results in all calli of several plant species are expected to reduce labor as well as somaclonal variation by increasing the subculture.

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.107-119
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• 1999

In this study, the induction regeneration of callus from immature embryo in trifoliata orange (Poncirus trifoliata RAFIN.) were accomplished. The embryogenic calli were induced from the immature embryo derived from seed when the calli were irradiated for 16hr at about 2,000 Lux in $\frac{1}{2}$ MS medium supplemented with 3% sucrose, and 44.4$\mu$M BA. Regeneration to whole plants was the most successful in MS medium containing 5.0$\mu$M BA. The yellowish callus was developed at 2 to 3 weeks of culture and the callus was changed from yellow to green at 5 to 6 weeks culture. In vitro regeneration was directly induced from embryogenic callus in MS medium containing 3% sucrose and 5.0$\mu$M BA. Multishoot was formed at 16 weeks culture. Moreover, when the root-formed plantlet was transplanted to soil, they grew to a whole plant. The compact cultured-cells were observed by light microscope after 4 weeks of cultivation and the embryogenic clumps were formed about the 5 weeks. At the same time, the neighboring cells were liquefied. In addition, differentiation of leaf and stem from the callus was observed after 12 weeks. The developed oil sacs and the profacicular cambium of the immature leaf were observed after 18 weeks. Therefore, we can see the considerable changes of cell arrangements according to the developmental stages of calli from trifoliata orange.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.461-471
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• 2011

This study was carried out to establish an in vitro culture method of callus having a high antioxidant activity from Ginkgo biloba L. Leaf explants were cultured on Murashige and Skoog's medium supplemented with various growth regulators. The explants were incubated in the dark or 3,000 lux cool-white light. Methanol extracts from incubated callus were evaluated for scavenging activity of the free radicals using DPPH. The best callus growth rate was achieved in MS medium combined with 10 ${\mu}M$ NAA and 5 ${\mu}M$ kinetin in the light condition. Total antioxidant activity of cell aggregates in suspension culture [MS medium supplemented with 10 ${\mu}M$ NAA in the light] was up to 80% of ascorbic acid. By means of HPLC analysis, quantification of the quercetin dehydrate and keamperol profiles from suspension callus was compared. Contents of quercetin dehydrate and keamperol from leaf extracts were 0.07 and 2.24 ${\mu}g/20{\mu}l$, and those from callus 0.56 and 0.18 ${\mu}g/20{\mu}l$, respectively.

• Journal of Plant Biotechnology
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• v.5 no.3
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• pp.173-179
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• 2003

The combination of a radiation technique with an in vitro culture system was appiled to develop submergence tolerant rice. The 3,000 $M_3$ lines with an average 80 percent of fertile grain were utilized for the selection of submergence tolerance. Salt tolerant lines were selected based on high plant height, root length and root number after submergence in plastic pots. Of the lines tested, the tolerant line (403-6) showed a dramatic difference in morphological traits under submergence compared to its original variety (Dongjinbyeo). It was suggested that genetic variations between the original variety and $M_3$-403-6 did exist. The levels of $\alpha$-amylase and alcohol dehydrogenase activities were significantly increased in the mutant line compared to its original variety. The mutant with greater tolerance showed less electrolyte leakage indicating a greater membrane integrity and better survival. Also, this line was much more resistant to a salt stress of $1.25\%$ than the original variety. The proline level of the line was significantly (p<0.01> higher than that of the original variety. The relationships between the inhibition of growth caused by stress and the physiological changes in the plant cell were discussed.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.18-18
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• 2010

Molecular insights on the role of plant growth promoting rhizobacteria (PGPR) in potato tuberization are reported in the present study. The PGPRwere isolated from the soil collected from potato fields of Highland Agricultural Research Centre, Pyeongchang, Korea and they were identified to the genus level based on the 16S rRNA sequence analysis. These PGPR were heat-killed, filtered and the filtrates were addedindividually at a concentration of $10^7\;cfu\;mL^{-1}$ in MS (Murashige and Skoog's) medium supplemented with 7% (w/v) sucrose to study their influence on in vitro potato tuberization. Tuber initiation occurred early in untreated control, while tuber growth was pronounced in case of PGPR treatments. The control explants showed tuber formation as a result of sub-apical swelling of stolons while several sessile tubers formed directly in the axils of nodal cuttings in case of PGPR treatments, which is an indication of strong induction for tuberization. Theexplants cultured on MS medium supplemented with bacterial isolate 6 (Bacillus firmus strain 40) showed highest average tuber yield (Ca. 12.56 g per treatment) after 30 days of culture, which was 3 folds increase over the untreated control. A significant increase in lipoxygenase (LOX1) mRNA expression and activity of LOX enzyme were also detected in the tubers induced on PGPR treatments as compared to untreated control. This LOX expression level correlated with increased tuber growth and tuber yield. Further studies focused on the role of bacteria cell wall components, growth regulators and signal molecules released by PGPR are under investigation to elicit clues for PGPR-mediated signal pathway controlling potato tuberization.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.288-298
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• 2014

We examined the efficacy of a bacterium for biocontrol of the root-knot nematode (RKN) Meloidogyne hapla in carrot (Daucus carota subsp. sativus) and tomato (Solanum lycopersicum). Among 542 bacterial isolates from various soils and plants, the highest nematode mortality was observed for treatments with isolate C1-7, which was identified as Bacillus cereus based on cultural and morphological characteristics, the Biolog program, and 16S rRNA sequencing analyses. The population density and the nematicidal activity of B. cereus C1-7 remained high until the end of culture in brain heart infusion broth, suggesting that it may have sustainable biocontrol potential. In pot experiments, the biocontrol efficacy of B. cereus C1-7 was high, showing complete inhibition of root gall or egg mass formation by RKN in carrot and tomato plants, and subsequently reducing RKN damage and suppressing nematode population growth, respectively. Light microscopy of RKN-infected carrot root tissues treated with C1-7 showed reduced formation of gall cells and fully developed giant cells, while extensive gall cells and fully mature giant cells with prominent cell wall ingrowths formed in the untreated control plants infected with RKNs. These histopathological characteristics may be the result of residual or systemic biocontrol activity of the bacterium, which may coincide with the biocontrol efficacies of nematodes in pots. These results suggest that B. cereus C1-7 can be used as a biocontrol agent for M. hapla.

• KSBB Journal
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• v.15 no.5
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• pp.537-540
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• 2000

In developing a HPLC purification process, it was hoped that a single chromatographic system would be sufficient to abtain pure paclitaxel in high yield. However, no such system was found, due in part to the complex taxoid profile of crude paclitaxel and to the rigorous nature of the product specification. A two step HPLC purification was adopted using reverse-phase separation on C(sub)18 as a first step, and normal-phase separation on silica as the final polishing step. Impurity profiles were established and maintained for paclitaxel, which identified and quantified each impurity observed in purified paclitaxel from these two steps, all impurities at or above 0.1% were identified. Results provide information for improving the quality control of paclitaxel production.

• Journal of Environmental Health Sciences
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• v.31 no.4 s.85
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• pp.287-293
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• 2005

Pollen has been used for Prevention or treatment of certain diseases such as diabetes, arthritis, or cancer in traditional medicine. In addition, pollen is under investigation as a host cell for a gene expression. This study was undertaken to evaluate the immunologic safety of pollen intake. BALB/c mice were administered with 500, 50,5, or 0.5 mg/kg bw of lily pollen for five times a week for four weeks through gastric intubation. Comparing the control mice administered with distilled water, no significant changes were observed in body weight gain, weight of liver, spleen, lung, and his-topathological findings of liver and kidney of the mice groups administered with the pollen. Plasma level of IgG1, IgG2a, and IgE was not different among the groups. When splenic B lymphocytes were stimulated in vitro with lipopolysaccharides for 7 days, level of IgGl and IgGwa produced in the culture supernatants was not significantly different among the groups. Furthermore, no significant alteration was observed in IL-4 and $IFN{\gamma}$ producing ability with splenic T lymphocytes stimulated in vitro with phytohemagglutinins for 48 hours between the pollen-administered and the control mice. Overall, this study suggests that the lily pollen intake is Inducing no significant modulation of humoral and cell-mediated immunity in mice.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.153-158
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• 1998

The internal structures of Arabidopsis thaliana infected with beet curly top virus (BCTV) were studied by light microscopy. Hyperplasia was observed in the inflorescence stems of Arabidopsis thaliana ecotype Sei-O at 2 weeks after BCTV-Logan inoculation and callus was induced on symptomatic tissues at 4 weeks after virus inoculation. The infection processes were revealed as follows: hyperplasia of phloem tissue, necrosis of hyperplastic phloems, lacuna formation of necrotic tissues, elongation and enlargement of cortex and epidermal cells surrounding the lacuna formed phloem tissues, induction of cell division in the enlarged cortex and epidermal cells, and induction of callus tissue. Callus formation on Arabidopsis was caused by the virus infection, and virus inclusion body was observed in both phloem and callus tissue by azure-A staining.