• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.77-86
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• 1995

To effectively modify tree function with genetic engineering, transgenes must be expressed at the proper level in the appropriate tissues at suitable developmental stages. Toward understanding the spatial and temporal expression of transgenes in woody plants, transgene expression was evaluated in three greenhouse-grown, transgenic lines of Populus alba ${\times}$ P. grandidentata hybrid clone 'Hansen'. All transgenic poplar lines possess constructs containing the bacterial nopaline synthase(nos) promoter linked to a neomycin phosphotransferase II(NPT II) selectable marker gene. In addition, each transgenic poplar line contains one of the following gene constructs : 1) a wound-inducible potato proteinase inhibitor II (pin2) promoter linked to a chloramphenicol acetyltransferase(CAT) reporter gene. 2) a nos promoter linked to a PIN2 structural gene : or 3) a Cauliflower Mosaic Virus 35s promoter linked to a PIN2 structural gene. Polymerase chain reaction(PCR) was used to verify the presence of foreign genes in the poplar genome. Enzyme-linked immunosorbent assays(ELISAs) were used to evaluate organ specific expression of the nos-NPT II construct. NPT II expression was detected in leaves, petioles, stems, and roots of transgenic poplar, thereby indicating that the nos promoter is potentially effective for general constitutive expression of transgenes. NPT expression varied among transgenic poplar lines and among organs for one transgenic line, Tr15. With Tr15, NPT II levels were highest in older leaves and petioles. These results indicate that screening of several transgenic lines may be required to identify lines with optimal transgene expression.

• Journal of Plant Biotechnology
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• v.6 no.1
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• pp.15-19
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• 2004

The expression of a chimeric transgene (nos-npt II) has been examined in 9 years old transgenic poplars (Populus koreana x P. nigra) growing in a nursery. The expression of the gene in twenty six independentely transformed plants were examined by 1) enzyme (NPT II) assay, 2) RT-PCR, and 3) resistance to kanamycin. High NPT II activities in young leaves of all the transformed plants were found even without a selection pressure for antibiotics for 9 years. However, the activity varied with the positions of leaves in the stem in that young leaves showed higher activity than did mature tissues. When leaf segments were cultured in the presence of 150 mg/l kanamycin, only those from young leaves produced vigorously growing callus. However, as in the case of NPTII assay, the leaf segments from mature leaves did not form callus well on the media. RT-PCR with nptII specific primers also showed that amplification products were observed only when RNAs from young tissues were used. The total RNA gel showed that while RNA in young leaves are relatively stable and in a large quantity, those in old leaves were mostly degraded. All the above results suggest that the gene is transcriptionally active only in young tissue even though it is attached to a constituitive promoter. Therefore, the expression of foreign gene in poplar plants seemed to be affected by the metabolic state of the cells and thus vary greatly with the developmental stages and the age of tissue.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.91-95
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• 2005

Agrobacterium tumefaciens-mediated immature embryo transformation was used to produce transgenic maize. Immature embryo of Hi II genotype were co-cultivated with strains Agrobacterium tumefaciens (C58C1) containing the binary vectors (pPTN290) carrying with Ubiquitin promoter-GUS gene as reporter gene and NOS promoter-nptll gene conferring resistance to paromomycin as selective agent. Seven embryogenic callus lines transformed showed the resistance in paromomycin antibiotics. Histochemical GUS assay showed that 7 individual lines transformed with the GUS gene were positive response among the transformants. Southern blot analysis revealed that the nptll gene segregated and expressed in their progeny.

• Journal of Korean Society of Forest Science
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• v.86 no.4
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• pp.407-414
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• 1997

The resistance of a non-transgenic poplar clone, 'Ogy' and three transgenic poplar lines to the cottonwood leaf beetle, Chrysomela scripta F., was evaluated by in vitro feeding. The lines were transformed with neomycin phosphotransferase II(NPT II) as a selectable marker, proteinase inhibitor II(pin2) as a resistance gene, and CaMV 35S as a promoter. An efficient method of sterilizing the beetle eggs and introducing them into plant tissue cultures was developed. The resistance of the transgenic lines was investigated in terms of effects tin leaf area consumed, insect weight, insect developmental stages, and plantlet root dry weight after feeding. Also, leaf area consumed was examined by leaf age as measured through leaf plastochron index(LPI). The leaf area consumed and insect weight were highly significant between transformants and control, and insect development in vitro was significant among the transgenic lines. Larval infestation was the most severe around LPI 4 to 5 which were young leaves. The system provided a quick, highly controlled method to screen developing transgenic plantlets directly.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.192-197
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• 2013

This study examined the phenotypic and molecular characteristics of the $2^{nd}$ clone ($T_0V_2$) plants of LeLs-antisense gene-transgenic chrysanthemum line (LeLs80) that exhibited non-branching, proving the relevance of these characteristics as a factor for use in environmental risk assessment. Results of the Southern blot analysis showed that three copies of the LeLs-antisense gene were introduced into the transgenic line, and northern analysis showed that the transcripted gene was normally expressed in the transgenic line. A flanking T-DNA sequencing method was used to determine that sequences of 184 and 464 bps flanked the LeLs-antisense gene in the transgenic line. These sequences, respectively, matched the 35S promoter for expression of the npt II gene and the NOS terminator for expression of the LeLs-antisense gene within the pCAMBIA 2300 vector.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.161-165
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• 2005

Agrobacterium tumefaciens-mediated cotyledonary explants transformation was used to produce transgenic cucumber. Cotyledonary explants of cucumber (c.v., Eunchim) were co-cultivated with strains Agrobaderium (LBA4404, GV3101, EHA101) containing the binary vector (pPTN289) carrying with CaMV 355 promoter-gus gene as reporter and NOS promoter-bar gene conferring resistance to glufosinate (herbicide Basta) as selectable marker. There was a significant difference in the transformation frequency depending Agrobacterium strains. The EHA101 of bacterial strains employed gave the maximum frequency (0.35%) for cucumber transformation. Histochemical gus and leaf painting assay showed that 15 individual lines were transgenic with the gus and bar gene. Southern blot analysis also revealed that the gus gene was successfully integrated into each genome of transgenic cucumber.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.257-262
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• 2005

Agrobacterium tumefaciens-mediated cotyledonary-node explants transformation was used to produce transgenic melon. Cotyledonary-node explants of melon (Cucumis melo L. cv. Super VIP) were co-cultivated with Agrobacterium strains (LBA4404, GV3101, EHA101) containing the binary vector (pPTN289) carrying with CaMV 35S promoter-gus gene as reporter gene and NOS promoter-bar gene conferring resistance to glufosinate (herbicide Basta) as selective agent, and the binary vector (pPTN290) carrying with Ubiquitin promoter-GUS gene and NOS promoter-nptll gene conferring resistance to paromomycin as selective agent, respectively. The maximum transformation efficiency (0.12%) was only obtained from the cotyledonary-node explants co-cultivated with EHA101 strain (pPTN289) on selection medium with 5 mg/L glufosinate and not produced a transgenic melon from the cotyledon or cotyledonary-node co-cultivated with other strains. Finally, five plants transformed showed the resistance in glufosinate antibiotic and the GUS positive response in leaf ($T_0$), flower ($T_0$), seeds ($T_1$) and plantlet ($T_1$). Southern blot analysis revealed that the gus gene integrated into each genome of transgenic melon.