• Journal of the Korean Society of Tobacco Science
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• v.9 no.2
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• pp.25-35
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• 1987

Effects of application time And rate of chlorine on the chlorine absorption and distribution at different stalk positions of the plants were Investigated in burley tobacco grown under the pot condition. Treatment consisted of 6 application times (from 2 weeks before transplanting to 8 weeks after transplanting with 2 weeks' interval) and 2 application rates (2g and 4g-KCl/pot) by 6X2 factorial experimental design. The tobacco plants took up the chlorine rapidly just after chlorine application, and the chlorine content of leaf was increased proportionally to the rate of chlorine application. The chlorine was accumulated when much in lower leaves when chlorine was applied early, while the chlorine accumulated much in upper leaves when chlorine was applied late. The chlorine content of leaf was negatively correlated to the degree of brightness, red color and yellow color of cured leaf. Significant Increases In cured leaf ratio, leaf thickness, leaf weight and weight Per unit leaf area of harvested leaf were obtained with increased chlorine application. When the chlorine was applied early, the leaf weight showed Increasing tendency.

• Mycobiology
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• v.29 no.1
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• pp.48-53
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• 2001

Plants have the ability to acquire an enhanced level of resistance to pathogen attack after being exposed to specific biotic stimuli. To obtain plant growth-promoting rhizobacteria inducing resistance against cucumber anthracnose by Colletotrichum orbiculare, more than 800 strains of rhizobacteria were screened in the greenhouse. Among these strains, Bacillus amyloliquefaciens solate EXTN-1 showed significant disease control efficacy on the plants. Induction of pathogenesis-related(PR-la) gene expression by EXTN-1 was assessed using tobacco plants transformed with PR-1a::$\beta$-glucuronidase(GUS) construct. GUS activities of tobacco treated with EXTN-1 and salicylic acid-treated transgenic tobacco were significantly higher than those of tobacco plants with other treatments. Gene expression analyses indicated that EXTN-1 induces the accumulation of defense-related genes of tobacco. The results showed that some defense genes are expressed by the treatment with EXTN-1 suggesting the similar resistance mechanism by salicylic acid.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.289.1-289
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• 1997

No Abstract, See Full Text

• Journal of Environmental Impact Assessment
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• v.22 no.2
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• pp.125-134
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• 2013

Plant virus coat (CP) gene-mediated protection is one of the best known approaches to protect against virus resistant transgenic plants. Transgenic N. benthamiana plants containing the CP gene of Zucchini green mottle mosaic virus (ZGMMV) were used for the environmental risk assessment of the living modified (LM) plants with plant virus resistance. The most optimal co-infection method of both ZGMMV and CMV (Cucumber mosaic virus) on Non-LM and CP-expressing LM tobacco plants was established and co-infection of CMV and ZGMMV was confirmed by polymerase chain reaction (PCR). To address the effects of LM tobacco plants on the mutation of the virus, in-vitro transcripts of CP and Replicase (Rep) derived from CMV and/or ZGMMV were inoculated onto Non-LM or LM tobacco plants. Mutation frequency of CP and Rep from CMV and ZGMMV was examined through six serial passages in Non-LM and LM tobacco plants. Little actual frequency of mutation was estimated, probably due to the limited number of transgenic plants tested in this study. However, it does not suggest environmental safety of these CP-mediated LM plants. Further study at a larger scale is needed to evaluate the environmental risk associated with the CP-expressing LM plants.

• The Plant Pathology Journal
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• v.15 no.1
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• pp.8-13
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• 1999

Hypersensitive cell death of plants during incompatible plant-pathogen interactions is one of the efficient defense mechanisms of plants against pathogen infections. For better understanding of the molecular mechanisms involved in the plant hypersensitive response (HR), TMV-induced biotic plant cell death and CuSO4-induced abiotic plant cell death were compared in terms of expression patterns of ten different defense-related genes as molecular markers. The genes include five pathogenesis-related protein genes, two plant secondary metabolite-associated genes, two oxidative stress-related genes and one wound-inducible gene isolated from tobacco. Northern blot analyses revealed that a same set of defense-related genes was induced during both biotic and abiotic cell death but with different time and magnitude. The expression of defense-related genes in tobacco plants was temporarily coincided with the time of cell death. However, when suspension cell cultures was used to monitor the expression of defense-related genes, different patterns of the gene expression were detected. This result implies that three are common and, in addition, also different branches of signaling pathways leading to the induced expression of defense-related genes in tobacco during the pathogen- and heavy metal-induced cell death.

• Journal of the Korean Society of Tobacco Science
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• v.13 no.1
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• pp.53-60
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• 1991

Seedling rot occurred on burley tobacco at the early growing stage after transplanting was surveyed in the Chonbuk province, the main area for burley tobacco production, during the 3 crop years from 1986. The incidence of disease was about 0.6-0.7% every year and major causal organisms were Pythium spp. More diseased plants were observed in the fields in which tobacco planted with improved mulching system than in that with any other mulching system. The temperature and relative humidity in the planting hole covered with polyethylene film for 11 days after transplanting were recorded by 27-45$^{\circ}C$ and 75~95%, respectively. The punched polyethylene film mulching field showed less diseased plants than that with improved mucking. In improved mulching system the longer period of mulching caused higher incidence of seedling rot(r=0.74**). Soil drench treatment of 200m1 of aqueous Metalaxyl Solution(125ppm) was effective to control the disease.

• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.292-296
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• 1994

Main tobacco diseases were surveyed on tobacco plants in the northern Kyeongbuk area to evaluate the effectiveness of current disease control techniques from 1993 to 1994. The major disease in seedlings was the anthracnose (Colletotrichum tabacum) but the mosaic (TMV) in adult plants. Wild fire (Psedomonas syringae pv. tabaci) and hollow stalk (Erwinia carotovora subsp. carotovora) were more severe in 1993 than those in 1994 because of more rain. Establishment of drain-outlet at the bottom of the temporary transplanting pot gave a significant reduction in anthracnose severity. Most farmers have ignored the protection effect of using milk during transplanting and the removal of diseased roots from the fields on mosaic (TMV). It was considered that the educating program on disease diagnosis and fungicide application might help farmers for the proper use of chemicals.

• Korean Journal of Pharmacognosy
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• v.28 no.4
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• pp.192-197
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• 1997

As a part of searching for new antitumor agents from natural products, 94 kinds of Chinese plants were extracted with petroleum ether/ether (1:1), ethyl acetate and methanol, successively and their cytotoxicities were evaluated against A549 (human lung carcinoma) cell line. Among them, six kinds of ether extracts, seven kinds of ethyl acetate extracts and one kind of methanol extracts showed significant cytotoxic activities (above 70% inhibition) at a concentration of $50\;{\mu}g/ml$. These results surest that they may be involved in natural sources with possible anticancer activities.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 1997.10a
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• pp.134-152
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• 1997

Plant viruses of tobacco including tobacco mosaic virus (TMV) and potato virus Y (PVY) cause severe economic losses in leaf-tobacco production. Cultural practices do not provide sufficient control against the viruses. Use of valuable resistant cultivars is most recommendable for the control of the viruses. However, conventional breeding programs are not always proper for the development of virus-resistant plants mostly owing to the frequent lack of genetic sources and introduction of their unwanted properties. Therefore, we tried to develop virus-resistant tobacco plants by transforming commercial tobacco cultivars, NC 82 and Burley 21, with coat protein (CP) or replicase (Nlb) genes of TMV and PVY necrosis strain (PVY-VN) with or without untranslated region (UTR) and with or without mutation. Each cDNA was cloned and inserted in plant expression vectors with 1 or 2 CaMV 35S promotors, and introduced into tobacco leaf tissues by Agrobacterium tumefaciens LBA 4404. Plants were regenerated in kanamycin-containing MS media. Regenerated plants were tested for resistance to TMV and PVY In these studies, we could obtain a TMV-resistant transgenic line transformed with TMV CP and 6 genetic lines with PVY-VN cDNAs out of 8 CP and replicase genes. In this presentation, resistance rates, verification of gene introduction in resistant plants, stability of resistance through generations, characteristics of viral multiplication and translocation in resistant plants, and resistance responses relative to inoculum potential and to various PVY strains will be shown. Yield and quality of leaf tobacco of a promising resistant tobacco line will be presented.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.59-63
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• 1975

A total of 40 virus infected tobacco plants (Nicotiana tabaccum L.) with various symptom types Were collected from Bucheon and Jeonju area by its symptoms were investigated on the incidence of tobacco mosaic virus (TMV), cucumber mosaic virus (CMV), alfalfa mosaic virus (AMV), potato virus X (PVX) and potato virus Y (PVY) by serological methods. van Slogteren's microprecipitin test was applied for the testing of PVX and PVY from infected plants and Ouchterlony agar double diffusion test was used for CMV, TMV and AMV. Results obtained are as follows: 1. TMV, CMV, AMV, PVX and PVY wcre found to occur on the tobacco plants growing in Korea. 2. The prevalence of each of these viruses among the 40 tobacco plants investigated was in the order of AMV: $(67.5\%)>CMV:(60.0\%)>TMY:(47.5\%)>PVY:(17.5\%)>PVX: (10.0\%).$ 3. In Burley variety, the percentage of infection by TMV was $15\%$, whereas it was as high as $80\%$ in Hicks variety. 4. Among the 40 tobacco plants investigated, $37.5\%$ showed infection with one kind of virus whereas the remaining $62.5\%$, revealed mixed infection with more than two different viruses.