• Korean Journal of Weed Science
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• v.8 no.1
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• pp.53-58
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• 1988

This study was carried out to determine effect of butachlor [N.-(buthoxymethyl)-2-chloro-N-(2,6-diethylphenyl) acetamide] and bialaphos [2-amino-4(hydroxy)(methyl) phosphionyl] butyryl-alanylalanine sodium salt on the germination of tobacco seed, induction and growth of callus from tobacco. Further, fatty acids and ammonia content of tobacco calli were determined. Bialaphos had no effect on tobacco seed germination, but the growth of seedling was markedly affected by an application of 10 ppm bialaphos. However, regardless of varieties tested, tobacco seed germination was completely inhibited by $5{\times}10^{-5}M$ of butachlor. At an application of $5{\times}10^{-5}M$ butachlor, tobacco seeds were to some extent germinated and showed further growth. Hyangcho among varieties tested, showed the most tolerant response to butachlor. In induction of callus from various tobacco varieties and their growth, aromatic type of tobacco varieties exhibited the most tolerance against bialaphos. However, no distinct varietal differences were determined in the treatment of butachlor. The major fatty acids identified in tobacco calli were palmitic, oleic and linoleic acid. No marked difference in terms of fatty acids was observed among tobacco varieties used, but it was observed that there was the higher ratio of quantity in unsaturated fatty acids over saturated one, bialaphos treatment accumulated about 9 times higher ammonia content than that of the untreated control, giving an evidence that bialaphos might inhibit glutamine synthetase activity.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.158-163
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• 2005

Virus-induced gene silencing (VIGS) is a recently developed gene transcript suppression technique for characterizing the function of plant genes. However, efficient VIGS has only been studied in a few plant species. In order to extend the application of VIGS, we examined whether a VIGS vector based on TRV would produce recognizable phenotypes in soybean. Here, we report that VIGS using the Tobacco rattle virus (TRV) viral vector can be used in several soybean cultivars employing various agro-inoculation methods including leaf infiltration, spray inoculation, and agrodrench. cDNA fragments of the soybean phytoene desaturase(PDS) was inserted into TRV RNA-2 vector. By agrodrench, we successfully silenced the expression of PDS encoding gene in soybean. The silenced phenotype of PDS was invariably obvious 3 weeks after inoculation with the TRV-based vector. Real-time RT-PCR analyses showed that the endogenous level of GmPDS transcripts was dramatically reduced in the silenced leaf tissues. These observations confirm that the silenced phenotype is closely correlated with the pattern of tissue expression. The TRV-based VIGS using agrodrench can be applied to functional genomics in a soybean plants to study genes involved in a wide range of biological processes. To our knowledge, this is the first high frequency VIGS method in soybean plants.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.77.2-78
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• 2003

An EREBP/AP2-type transcription factor (CaPFl) was isolated by DDRT-PCR following inoculation of soybean pustule pathogen Xanthomonas axonopodis pv. glycines Bra which induces HR on pepper leaves. Genomic Southern blot analysis revealed that the CaPFl gene is present as a single copy within the hot pepper genome. The deduced amino acid sequence of CaPFl has two potential nuclear localization signals, a possible acidic activation domain, and an EREBP/AP2 motif that could bind to a conserved cis- element present in promoter region of many stress-induced genes. The mRNA level of CaPFl was induced by both biotic and abiotic stresses. We observed higher-level transcripts in resistance-induced pepper tissues than diseased tissues. Expression of CaPFl is also induced upon various abiotic stresses including ethephon, MeJA, cold stress, drought stress and salt stress treatments. To study the role of CPFI in plant, transgenic Arabidopsis and tobacco plants which express higher level of pepper CaPFl were generated. Global gene expression analysis of transgenic Arabidopsis by cDNA microarray indicated that expression of CaPFl in transgenic plants affect the expression of quite a few GCC box and DRE/CRT box-containing genes. Furthermore, the transgenic Arabidopsis and tobacco plant, expressing CaPFl showed tolerance against freezing temperature and enhanced resistance to Pseudomonas syrnigae pv. tabaci. Taken together, these results indicated that CaPFl is a novel EREBP/AP2 transcription factor in hot pepper plant and it may has a significant role(s) in regulation of biotic and abiotic stresses in plant.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.85-92
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• 2002

A new isolate of Cucumber mosaic virus (CMV), identified as Li-CMV was isolated from a diseased Korean native lily (Lithium tsingtauense Gilg). Biological and serological properties of Li-CMV were characterized, and reverse transcription-polymerase chain reaction (RT-PCR) analysis, restriction enzyme profiling of RT-PCR products, and nucleotide sequence analysis of RNA3 of the virus were performed in this study. Remarkable differences in symptoms between Li-CMV and ordinary CMV strains were found in tobacco plants and Datura stramonium. Li-CMV-infected tobacco plants (cv. Xanthi-nc and cv. Samsun) induced chlorotic ringspots on uninoculated upper leaves, and the symptom expression was delayed or faint whereas, ordinary CMV strains induced green mosaic symptoms on the plant. Systemic infections were observed on Nicotiana benthamiana with severe mosaic symptom. Restriction mapping analysis of RT-PCR products using MspI showed that Li-CMV belonged to CMV subgroup I. A full-length CDNA copy of RNA3 for the virus was amplified by RT-PCR, cloned, and its complete nucleotide sequence was determined. The RNA3 of Li-CMV was 2, 232 nucleotides long, and consisted of two open reading frames of 843 and 657 bases encoding 3a protein (movement protein) and coat protein, respectively. Results of this study indicate that Li-CMV is a novel strain and belongs to subgroup I of CMV in the genus Cucumovirus.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.339-343
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• 2000

When plants are exposed to subfreezing temperatures ice crystals are forming within extracelluar space in leaves. The growth of ice crystal is closely related to the degree of freezing injury. It was shown that an antifreeze protein binds to an ice nucleator through hydrogen bonds to prevent growth of ice crystal and also reduces freezing damage. The antifreeze proteins in plants are similar to PR proteins but only the PR proteins induced upon cold acclimation were shown to have dual functions in antifreezing as well as antifungal activities. Three of the genes encoded for CLP, GLP, and TLP were isolated from barley and Kentucky bluegrass based on amino acid sequence revealed after purification and low temperature-inducibility as shown in analysis of the protein. The deduced amino acid of the genes cloned showed a signal for secretion into extracellular space where the antifreezing activity sup-posed to work. The western analysis using the antisera raised against the antifreeze proteins showed a positive correlation between the amount of the protein and the level of freeze tolerance among different cultivars of barely. Besides it was revealed that TLP is responsible for a freeze tolerance induced by a treatment of trinexapac ethyl in Kentucky bluegrass. Analysis of an overwintering wild rice, Oryza rufipogon also showed that an acquisition of freeze tolerance relied on accumulation of the protein similar to CLP. The more direct evidence for the role of CLP in freeze tolerance was made with the analysis of the transgenic tobacco showing extracellular accumulation of CLP and enhanced freeze tolerance measured by amount of ion leakage and rate of photosynthetic electron transport upon freezing. These antifreeze proteins genes will be good candidates for transformation into crops such as lettuce and strawberry to develop into the new crops capable of freeze-storage and such as rose and grape to enhance a freeze tolerance for a safe survival during winter.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.271-275
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• 2007

In the chloroplast transformation process, a chloroplast containing transformed chloroplast genome copies should be selected over wild-type chloroplasts on selection medium. It is more effective for a cell to become homoplasmic if the cell contains smaller number of chloroplasts. Therefore, to reduce the number of chloroplasts in mesophyll cells in tobacco, we overexpressed FtsZ to generate transgenic plants, of which mesophyll cell contained a few enlarged chloroplasts contrast to a wild-type mesophyll cell containing approximately 100 chloroplasts. It was demonstrated that transgenic leaf tissues comprising cells with a few enlarged chloroplasts gave rise to approximately 40% higher frequency of chloroplast-transformed adventitious shoots.

• Current Research on Agriculture and Life Sciences
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• v.17
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• pp.15-20
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• 1999

To investigate the function of the chloroplast small heat shock protein (small HSP), transgenic tobacco plants (Nicotiana tabacum L., cv. SRI) that show constitutive expression of the chloroplast small HSP were generated. Effects of constitutive expression of the introduced gene on thermotolerance were first probed with the chlorophyll fluorescence. After a 5-min incubation of leaf discs at high temperatures, an increase in the Fo level and a decrease in the Fv level, indications of separation of LHCII from PSII and inactivation of electron transport reactions in PSII, were mitigated by constitutive expression of the small HSP. When tobacco plantlets grown in Petri dishes were incubated at $52^{\circ}C$ for 45 min and subsequently incubated at $25^{\circ}C$, leaf color of nontransformants was gradually became white and all plantlets finally were died. Under conditions in which all nontransformants were dying, more than 80% of the transformants remained green and survived. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery during heat stress.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.13-18
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• 2000

To investigate the function of chloroplast small HSP, transgenic tobacco plants (Nicotiana tabacum L. cv. Samsun) that constitutively overexpress the chloroplast small HSP (NtHSP21) from N. tabacum cv. Petit Havana SR1 were generated. Five homozygous lines of transformants showing different constitutive expression levels of the NtHSP21 were selected. To determine whether constitutive overexpression of NtHSP21 protein affects thermotolerance, wild-type and transformants were grown in Petri dishes, heat-stressed at 52$^{\circ}C$ for 45 min, and then incubated in normal growth condition. When heat-stressed wild-type plantlets were incubated at $25^{\circ}C$, leaf color gradually became white and all trio plantlets finally died within a week. As for the transformants, however, more than 70% of them remained green and survived under the conditions in which all the wild-type plants were dying. It was also found that the levels of NtHSP21 were correlated with the degree of thermotolerance. These results suggest that the NtHSP21 protein in transformants is responsible for the increase in thermotolerance.

• Korean journal of applied entomology
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• v.38 no.3
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• pp.225-230
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• 1999

This study was conducted to determine the effect of pupal development and adult longevity of Spodoptera litura larvae reared on leaves of different leguminos plants of 11 varieties or cultivars. Pupal duration varied from 8.7 to 9.5 days depending upon different diets and duration of female pupa (8.3~9.1 days) was about 1 day shorter than that of male's (9.4~10.1 days). Prepupal an postpupal duration were 1.7 to 2.0 days and 6.7 to 7.7 days, respectively. Pupal weight ranged from 0.23g to 0.43g for female and 0.24g to 0.35 g for male. Percent change of pupal weight was lowest (11%) on geomjeongkong-1 and highest (16%) on bukwangkong. Adult longevity was in ranging from 7.8 days on dongbu to 11.2 days on bukwangkong and tended to become slightly longer in female than tin male. Significant relationships were recognized between moisture content of feeding leaf, the pupal duration and weight and adult longevity.

• Research in Plant Disease
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• v.24 no.1
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• pp.81-85
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• 2018

Chinese artichoke (Stachys sieboldii Miq.) belongs to herbaceous perennial plants of Labiatea and is cultivated as edible and medicinal crops in China, Japan and Korea. A Chinese artichoke plant showing virus-like symptoms was collected in Chungju, Korea. Plant sap of the sample was inoculated in Nicotiana tabacum cv. Xanthi-nc, Chenopodium quinoa and Chenopodium amaranticolor. Necrotic local lesions were observed in the inoculated leaves of N. tabacum cv. Xanthi-nc and C. amaranticolor, C. quinoa with systemic chlorotic spots and mosaic symptoms on the upper leaves. The disease reactions on indicator plants suggested that the collected Chinese artichoke sample was mixed-infected with different viruses. We detected three viruses by RT-PCR analysis using genus- and species-specific primer sets for Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV). This study is the first report of a mixed infection of three viruses in Chinese artichoke in Korea.