• Journal of the Korean Society of Tobacco Science
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• v.26 no.1
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• pp.7-12
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• 2004

Effect of Decyl Alcohol Emulsifiable Concentrate on sucker control and phytotoxicity to tobacco plants were tested on flue-cured tobacco and burley tobacco. There were no significant differences of sucker inhibition effect between Decyl Alcohol EC and Choline Salt of Maleic Hydrazide Soluble Concentrate(control chemical). Tobacco plants applied with Decyl Alcohol EC showed no visible symptoms of phytotoxicity and no significant differences of number of leaves, leaf length, leaf width, and stalkt height. Yields increased considerably with no difference from ones of plants treated with control chemical.

• Journal of Applied Biological Chemistry
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• v.43 no.2
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• pp.69-73
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• 2000

In order to understand the biological role of calmodulin in plants, transgenic plants expressing a mutant calmodulin (VU-4, Iys to ile-115) have been analyzed. We found that tobacco plants expressing VU-4 calmodulin have approximately twofold higher $\gamma$-aminobutyric acid (GABA) levels than the control plants. Cell suspension cultures established from the stem explants of the transgenic tobacco seedlings also have higher levels of GABA than the control cell cultures. Specific activity of glutamate decarboxylase (GAD), which catalyzes the decarboxylation of glutamate to $CO_2$ and GABA, of the transgenic tobacco cell extracts was about twofold higher than the activity of the control cell extracts. Western-blot analysis showed that the GAD is highly expressed in the transgenic tobacco plants. GAD partially purified from tobacco cell extracts showed approximately threefold $Ca^{2+}$/calmodulin-dependent activation. These data suggest that GABA synthesis in the transgenic tobacco plants is elevated, possibly due to higher levels of the calmodulin-dependent GAD enzyme and/or as a result of enhanced activation due to increased levels of the foreign calmodulin.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.1
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• pp.12-19
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• 2003

Transgenic tobacco plants were selected by using the transformation of putrescine N-methyltransferase(PMT) gene, the key enzyme in diverting polyamine metabolism towards the biosynthesis of nicotine. PMT was fused in reverse orientation to the CaMV 35S promoter of the plant expression vector pBTEX(pPAB3) to produce tobacco plants of low nicotine content. To compare nicotine content, only pBTEX vector and PMT gene which was fused in forward orientation to the CaMV 35S promoter(pPAB2) were also transformed to the leaf tobacco plants(Nicotiana tabacum cv. NC82 and N. tabacum cv. Br2l). The presence of sense- and antisense-PMT gene, and pBTEX vector in the transgenic plant was confirmed by genomic PCR.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.50-56
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• 1998

The complementary DNA (cDNA) of potato virus Y- vein necrosis strain (PVY-VN) replicase gene (Nlb) was transformed into tobacco (Nicotiana tabacum cv. Burley 21) plants. Out of 25 putative transformants regenerated, 3 were resistant to PVY-VN, one highly resistant plant with no symptom until seed harvest time and the other two with mild chlorotic spot symptoms at late stages after infection. No symptom was observed in the highly resistant plant, while mild vein necrotic symptoms were developed on suckers of the moderately resistant plants after seed harvest time, In the first generation (T1) via self fertilization, resistance to susceptibility frequency in transgenic plants from the highly resistant transformant was about 3 : 1, while it was lowered much (about 1:2 and 1:19) in T1 of the moderately resistant transformants. In the second generation (T2) of the highly resistant plant, resistance frequencies were similar to T1, but resistance levels varied greatly and appeared to be decreased. Key words : potato virus Y, viral replicate gene, transgenic tobacco plants, resistance.

• Journal of the Korean Society of Tobacco Science
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• v.26 no.2 s.52
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• pp.79-84
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• 2004

During the screening of antiviral substances having inhibitory effects on tobacco mosaic virus (TMV) infection to tobacco plants, we found a bacterial isolate KTGBP10, which was identified as a Stenotrophomonas sp., strongly inhibited the infection of TMV. When the culture filtrate from KTGBP10 was applied on the upper surface of leaves of Xanthi-nc tobacco plants at the same time or 24 hours before TMV inoculation, almost complete inhibition of TMV infection was achieved. And $40\%$ inhibition was shown with application of the culture filtrate to the under surface of leaves. In field trials, transmission of TMV from diseased seedlings to the healthy ones during transplanting work was reduced by $87.1\~92.6\%$ when the culture filtrate or cell suspension was sprayed onto the tobacco seedlings, cv. NC82, 24 hours before transplanting. No toxic effect was observed on the tobacco plants. When the broth filtrate of KTGBP10 was supplied by soaking through the cut-leaves before and/or after virus inoculation, the TMV infection was also inhibited by $50.4\~65.3\%$.

• Journal of Plant Biotechnology
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• v.4 no.3
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• pp.117-122
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• 2002

Cotton Glutathione S-Transferase(GST: EC 2.5.1.18) was cloned and Gh-5 cDNA was overexpressed in tobacco (Nicotiana tabacum) plants. The transformation of cotton GST in tobacco plant was confirmed by northern blot analysis. Type I and Type II transcript patterns were identified in Gh-5 transgenic tobacco plants. Type I transcripts was only discussed in this paper. Glutathione and 1-chloro-2,4-dinitrobenzene (CDNB) were used as the substrates, and the activity of GST in the type I transgenic plants was about 2.5-fold higher than the non-expressers and wild type tobacco plants. The expression of cotton GST in tobacco plants proved that Gh-5 could be translated into functional protein. Type I transgenic plants produced functional GST in the cells. Type I showed higher GST specific activity than Type II in the transgenic plants. Control and transgenic seedlings were grown in the growth chamber and under the light at 15$^{\circ}C$, and the effects of cotton GST in the seedlings was evaluated. The growth rate of Gh-5 overexpressors was better than the control and non-transgenic tobacco plants. Salinity tolerance was also analyzed on the seeds of transgenic plants. Seeds of Gh-5 overexpressors and the wild type tobacco seedlings were germinated and grown at 0, 50, 100, 150, and 200 mM NaCl solution. Gh-5 transgenic seedlings showed higher growth rate over control seedlings at both 50 and 100 mM NaCl solution. But at 0, 150, and 200 mM NaCl concentration, the difference in growth rate was not detected.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.583-592
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• 2022

Root-knot nematode disease is a widespread and catastrophic disease of tobacco. However, little is known about the relationship between rhizosphere bacterial community and root-knot nematode disease. This study used 16S rRNA gene sequencing and PICRUSt to assess bacterial community structure and function changes in rhizosphere soil from Meloidogyne incognita-infected tobacco plants. We studied the rhizosphere bacterial community structure of M. incognita-infected and uninfected tobacco plants through a paired comparison design in two regions of tobacco planting area, Yuxi and Jiuxiang of Yunnan Province, southwest China. According to the findings, M. incognita infection can alter the bacterial population in the soil. Uninfested soil has more operational taxonomic unit numbers and richness than infested soil. Principal Coordinate Analysis revealed clear separations between bacterial communities from infested and uninfested soil, indicating that different infection conditions resulted in significantly different bacterial community structures in soils. Firmicutes was prevalent in infested soil, but Chloroflexi and Acidobacteria were prevalent in uninfested soil. Sphingomonas, Streptomyces, and Bradyrhizobium were the dominant bacteria genera, and their abundance were higher in infested soil. By PICRUSt analysis, some metabolism-related functions and signal transduction functions of the rhizosphere bacterial community in the M. incognita infection-tobacco plants had a higher relative abundance than those uninfected. As a result, rhizosphere soils from tobacco plants infected with M. incognita showed considerable bacterial community structure and function alterations.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.77-81
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• 1999

Tobacco plants(Nicotiana tabacum cv. NC82) transformed with TMV CP cDNA were self-fertilized until 8th generation (R$_{8}$), and the transgenic plants from 6th to 8th generation were analized for their resistance to tobacco mosaic virus(TMV) and stability of the gene expression. The 6th generation of the plants(R$_{6}$) showed high resistance(81-91 %) to TMV at eight weeks after artificial inoculation with the virus. The transgenic cell line 601 was the most prominant in the expression of resistance. 98 % of the plants showed no symptom without any agronomic phynotepe variation when they were inoculated with the virus in a experimental field. However, 2% of the plants were revealed as delay type of symptom with mild mosaic on a few leaves. The viral resistance in greenhouse tests of the 7th generation (R$_{7}$) was 54-64%, and the number of delay type plants were increased than that of 6th generation plants. In the 8th generation, 81 % of the plants was complete resistant to the virus. The TMV CP cDNA of the transgenic plants of each generation was also confirmed by genomic PCR, and there was no systemic viral multiplication in the resistant plants. It suggests that the viral resistance and gene expression of the transgenic plants might be stable through the generations.ons.s.

• Journal of the Korean Society of Tobacco Science
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• v.3 no.2
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• pp.131-133
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• 1981

The hollow stalk, caused by Erwinia carotovors var. carotovora, is probaly the most devastating disease to burley tobacco in Korea. There are two modes of infection to tobacco plants: the primary infection along the plant stem from soil and the secondary one from the topped end of plants. The secondary infection rate could be reduced to almost zero by applying an antibiotic, streptomycin sulfate(400 ppm solution), right after topping.

• BMB Reports
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• v.29 no.4
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• pp.308-313
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• 1996

An 1.4 kb of the fad3 cDNA encoding microsomal linoleic acid desaturase catalyzing the conversion of linoleic acid (18:2, ${\omega}-6$) to linolenic acid (18:2, ${\omega}-3$) was introduced into tobacco plants by the Agrobacterium-mediated plant transformation, Among the transgenic tobacco plants conferring kanamycin resistance, five transformants showing increment in unsaturated fatty acid contents were selected and further analyzed for the transgenecity, In genomic Southern blot analyses, copy numbers of the integrated fad3 DNA in chromosomal DNA of the five transgenic tobacco plants were varied among the transgenic lines. By Northern blot analyses, the abundancy of the fad3 mRNA transcript directed by Cauliflower Mosaic Virus 35S promoter was consistent with the relative copy number of the fad3 DNA integrated in the chromosome of transgenic tobacco plants. When compared with the wild type, accumulation of linolenic acid in transgenic tobacco roots was elevated 3.7- to 4.7-fold showing a corresponding decrease in the linoleic acid contents; however, slight increments for linolenic acid were noticed in transgenic leaf tissues. These results indicated that the elevated level of fad3 expression is achieved in transgenic tobacco plants.