• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.245-250
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• 1998

Tobacco mosaic virus(TMV) coat protein cDNA was transformed to Nicotiana tabacum cv. NC82 and the transgenic tobacco plants resistant to TMV infection were isolated in the next generation. The expression of TMV coat protein cDNA and genetic stability of the fifth generation of TMV resistant transgenic tobacco plants at the higher temperature were investigated. The TMV coat protein cDNA was amplified by genomic PCR in all the TMV resistant transgenic tobacco plants. The TMV coat protein expressed in the transgenic tobacco plants was detected at very low level by immunoblot hybridization. Even in tansgenic plants that showed the viral symptom only on very late sucker growth (delay type plants), the coat protein expression in the suckers was much less than that of susceptible tobacco infected with TMV. The TMV coat protein expressed in the transgenic tobacco plants was below 0.01% of total protein. Transcription and expression of the coat protein cDNA in delay type plants were observbed at high temperature (38$^{\circ}C$), and TMV replication was suppressed at both 28$^{\circ}C$ and 38$^{\circ}C$. This indicates that unlike the resistance conferred by 'N' gene. TMV resistance of transgenic tobacco plant won't break down at high temperature.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.101-106
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• 1996

Tobacco mosaic virus (TMV) tomato strain was isolated from tomato "Seo-Kwang" in Korea. The virion was purified by density gradient centrifugation, and total viral RNA was isolated from the purified particles. Coat protein (CP) cDNA of the virus was synthesized by RT-PCR, and the purified cDNA fragment was subcloned to pBluescript II SK-. The analysis of nucleotide sequence showed that this cDNA was 693 nucleotides long from the insert of clone p1571 and p1572 which contain complete codons of the viral coat protein gene (474 nucleotides) and 3' untranslated region. The nucleotides of coat protein encoding cDNA of the strain were 6 nucleotides less than that of TMV common strain isolated from tobacco plant in Korea. The CP gene showed 70% maximum homology with that of the common strain in the nucleotide level and 86% maximum homology in amino acid level.cid level.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.374-379
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• 1995

The cDNA of tobacco mosaic virus-pepper strain (TMV-P) coat protein (CP) genes were introduced into tobacco plants (Nicotiana tabacum cv. Samsun nn) using a binary Ti plasmid vector of Agrobacterium tumefaciens. these cDNAs introduced into tobacco plants were detected by polymerase chain reaction. Symptom development was distinctly suppressed in the transgenic plant introduced buy sense CP cDNA when the plant was inoculated with TMV-P, while in transgenic tobacco plants of antisense CP gene, symptom development was not suppressed as in non-transgenic plants. TMV-P concentration in the sense CP transgenic tobacco plant was decreased to 1/14 of the concentration in non-transgenic plants. Expression of the kanamycin resistance gene of these transgenic plants could be detected in the progeny.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.182-186
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• 1996

국내에서 재배되고 있는 고추(Capsicum annuum L.)로부터 분리된 TMV pepper 계통을 density gradient centrifugation을 이용하여 순화하였다. 이로부터 바이러스의 total RNA를 분리하였고 RT-PCR에 의하여 TMV pepper 계통의 외피단백질 cDNA를 합성, 증폭하였으며 이를 pBluescript II SK- 벡터에 재조합하였다. 본 실험에서 바이러스 외피단백질과 3` non-coding region을 포함하는 재조합 클론 p1561과 p1562로부터 염기서열을 분석하였고 그 결과로 477 염기의 외피단백질 유전자를 포함하는 691 염기가 합성되었음을 확인하였으며 이것과 TMV common 계통으로부터 합성된 외피단백질 cDNA와의 최대 유사도는 69%였다. 또한 유추된 아미노산 서열에서 이들 두 계통간의 최대 유사도는 81%였다.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.2
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• pp.161-166
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• 1993

A double - stranded cDNA fragment (436bp) encoding coat protein of tobacco mosaic virus(TMV) was derived from the total 480nucleotides gene after reverse transcription of TMV RNA, and subclorled into a plant expression vector pBl 121, resulting in pBL 430. The plasmid DNA containing this chimeric gene was moved from E. cofi to Agrobacterium tumefaciens strain A28l, and was introduced in시 the tobacco plant by the Agrobocterium Ti - mediated transformtion system. The transformants were selected on a selection media containing kanamycin. The shoots add roots could be differentiated from the explants and whole plants were obtained. From Southern blot hybridization analysis, DNA extracted from transformants, it could be conformed that the chimeric gene fragment was inserted into the genomic DNA of tobacco plant.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.66-70
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• 1998

TMV resistant lines (TRLs) originated from the Blo plant of Nicotiana tabacum cv. NC82 transformed with TMV coat protein cDNA which initially showed delayed disease symptom were selected for increased resistance in each subsequent generation. The result of field experiment of the transgenic tobacco lines in the fifth generation for TMV resistance and their response to other tobacco diseases (black shank, bacterial wilt, and powdery mildew) is described in this report. When fifteen TRLs of the fifth generation were tested for TMV resistance by mechanically inoculating the individual plants, over 95 percent of the plants of 6 lines showed complete resistance even 8 weeks after the inoculation. Average frequency of the resistant plants in TRLs of the fifth generation 8 weeks after the inoculation was 87%. Stable insertion and expression of TMV coat protein cDNA in the fifth generation of the transgenic tobacco plant were confirmed by PCR and immunoblot hybridization, respectively. All TRLs were resistant to the black shank but were susceptible to the bacterial wilt disease and the powdery mildew to the same degree as non-transgenic NC82 was. Therefore, it was indicated that the phenotypes related at least to disease resistance were not changed in the transgenic tobacco. Key words : TMV CP cDNA, TMV resistant tobacco plant, transformation.

• 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.