• BMB Reports
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• v.32 no.1
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• pp.1-5
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• 1999

In order to understand the biological role of calmodulin in plants, transgenic tobacco plants expressing a calmodulin mutant (VU-4 calmodulin, lys to ile-115) gene have been analyzed. SDS-PAGE and Western-blot analyses showed that the foreign calmodulin mutant is stably and highly expressed in the transgenic tobacco plants. The levels of $H_2O_2$were elevated approximately 2-fold in the transgenic plants. Furthermore, the transgenic tobacco plants have more than 6-fold higher levels of NADPH compared to control tobacco plants. The present findings, combined with previous data showing differences in the susceptibility of the transgenic tobacco seeds and normal tobacco seeds to fungal contamination (Oh and Yang, 1996), suggest that the expression of the calmodulin derivative gene in tobacco plants could increase resistance to infection by fungal pathogens.

• 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.11 no.1
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• pp.80-86
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• 1995

The cDNA of CMV-As satellite RNA was introduced into tobacco plants (Nicotiana tabacum cv. Samsun NN) using a binary Ti plasmid vector system of Agrobacterium tumefaciens. The cDNA of satellite RNA introduced into tobacco plants was detected by polymerase chain reaction (PCR) and molecular hybridization analyses. Symptom development was distinctly suppressed in the transgenic tobacco plants when inoculated with CMV-Co. CMV concentration in the transgenic tobacco plants was decreased to 1/40 of non-transgenic tobacco plants. The kanamycin resistance gene of the transgenic tobacco plants was also detected in the progeny.

• 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.

• 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 Plant Biotechnology
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• v.34 no.1
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• pp.31-36
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• 2007

Though higher plants car not metabolize D-amino acid, many prokaryotes and eukaryotes have the D-amino acid metabolism. Therefore, we transformed tobacco plants with D-amino acid oxidase (DAO), which can metabolize D-amino acid, and confirmed that transgenic tobacco plants might metabolize D-amino acid. Transgenic tobacco plants were survived a high concentration of D-serine, however non-transgenic plants were not grown on D-serine medium. From Southern and Northern blot analysis, transgenic tobacco plants selected on D-serine medium were confirmed by insert and expression of transgene. $T_{1}$ tobacco seeds derived $T_{0}$ tobacco plants selfing were grown on D-serine medium and showed normal phenotype compared to wild tobacco plants. Transgenic tobacco plants displayed the metabolic capability of D-serine. Therefore, we suggested that DAO is useful selectable marker gene for plant transformation.

• 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.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.41-45
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• 2001

Transgenic tobacco plants were produced by the transformation of ginseng CAB gene using Agrobacterium tumefaciens LBA4404. The presence of CAB gene in the second generation of transgenic tobacco plant was confirmed by genomic PCR. The photosynthetic ability of transgenic plants was higher than normal tobacco plants and the maximum photosynthetic point of transgenic and normal tobacco plants was 500 $\mu$mol m$^{-2}$ s$^{-1}$ . The photosynthesis of C7, C11, 1, C14 cell lines was higher than normal plants at all the light intensities investigated. The photosynthesis of C2, C11, C14 cell lines in 90% dark condition was higher than normal plants. The chlorophyll contents of transgenic tobacco plants were almost same as normal plants. The % of dry weight, nicotine content, total sugar and nitrogen contents of harvested transgenic tobacco plant leaves were almost same as normal plants.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.57-65
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• 1998

This study was conducted to develop a resistant tobarro against Potato virus Y (PVY) by transformation of the plants with genetically engineered viral genes. The complimentary DNAs (cDNAS) of potato virus Y-necrosis strain (PVY-Vn) replicase mutant genes (3'-deleted, 5'-deleted and ADD-mutant Nlbs) were synthesized through RT-PCR by using purified PVY-VN RNA and synthesized primers, and cloned in the sense orientation into a plant expression vector (pMBPI), The cDNAS of the genes were transferred into Agrobacterium tumefaciens LBA 4404, and then transformed into tobacco (Nicotiana tabacum cv. Burley 21) plants. Regenerated plants were tested for PVY resistance by inoculation test; 13 transgenic plants including 7 for 3'-deleted Nlb, 3 for 5'-deleted Nlb, and 3 for ADD-mutant Nlb appeared to be resistant at 4 weeks after inoculation with PVY-VN. Among the 13 transgenic tobacco plants, 8 plants had no symptom up to 14 weeks after inoculation. The progenies ($T_1$) from self-fertilization of the transgenic lines varied 0.0% to 81.2% in their resistance (% of resistant plants). The analysis of Nlb-31deleted, -5'deleted and -ADD mutant in the $T_1$ plants by polymerase chain reaction (PCR) showed that Nlb-3'deleted, -5'deleted and -ADD mutants were detected in all of the resistant plants. These results suggest that the PVY resistance was inherited in the $T_1$ generation.

• Journal of Plant Biotechnology
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• v.2 no.1
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• pp.25-28
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• 2000

The anthocyanin gene encoding flavonoid 3',5'-hydroxylase(F3,5H) was normally expressed in Nicotiana tobacco (Xanthi) plants cocultivated with Agrobacterium tumefaciens LBA4404 carrying egg plant flavonoid 3',5'-hydroxylase cDNA. Northern blot analysis showed the normal expression of F3', 5'H gene from transgenic plants. Here we found the phenotypic differences between transgenic plants and wild-type plants. The petal shape of transgenic plants showed more round shape and around petal tube area was compared to that of wild-type tobacco plants. And the petal color of transgenic plants was much lighter than that of wild-type tobacco plants.