• Korean Journal of Breeding Science
• /
• v.40 no.2
• /
• pp.128-135
• /
• 2008

Herbicide resistance is the most common trait being tested and thus herbicide?resistant genetically modified plants are now the most widely cultivated worldwide. Here we developed herbicide?resistant transgenic Agrostis mongolica Roshev. by employing an efficient Agrobacterium?mediated transformation procedure with 25.2% of transformation efficiency. The identification and employment of regenerable and reproducible type of callus was one of the most critical factors to ensure success in this study. PCR analysis confirmed that the bar transgene was integrated into the genome of transgenic plants. The expression of 35S?bar gene was confirmed by Northern blot analysis. The transgenic plants showed complete resistance to herbicide, indicating that the bar gene is functional in transgenic plants.

• Journal of Plant Biotechnology
• /
• v.2 no.1
• /
• pp.35-41
• /
• 2000

Transgenic cabbage (Brassica oleracea ssp. capitata) plants resistant to the commercial herbicide Bast $a^{R}$ were obtained by Agrobacterium tumefaciens - mediated transformation. Hypocotyl segments of in vitro grown plants were infected with Agrobacterium tumefaciens LBA 4404 harboring plasmid pMOG6-Bar which contains hpt and bar genes. Explants were cultured on callus induction medium (MS basal medium + 1 mg/L NAA + 2 mg/L BA + 2 mg/L AgN $O_3$+ 100 mg/L carbenicillin + 250 mg/L cefotaxime) supplemented with 15 mg/L hygromycin. Hygromycin resistant calluses were transferred to shoot regeneration medium (MS basal medium + 0.1 mg/L NAA + 2 mg/L BA + 3% sucrose + 2 mg/L AgN $O_3$+ 15 mg/L hygromycin + 250 mg/L cefotaxime + 100 mg/L carbenicillin). In order to induce roots, elongated shoots were placed on the MS medium without plant growth regulators and hygromycin. Southern blot analysis of several putative transgenic plants indicated that one to five intact copies of Apt and bar genes were incorporated into the genome. Expression of bar gene was confirmed by Northern blot analysis and by herbicide resistant phenotype. Seed progeny from self-pollinated transformants expressed the herbicide resistance and showed Mendelian segregation of the introduced gene.e.

• Journal of Life Science
• /
• v.7 no.3
• /
• pp.172-175
• /
• 1997

Transgenic hybrid poplar subclones containing herbicide glyphosate resistant gene (aroA) were treated with ozone at the concentration of 100 nL L$^{-1}$ for 6 hr for 5 consecutive days. The foreign gene expression in leaves of all treated plants was reduced both at transcriptional and translational levels confirmed by Northern and Western blot analysis, respectively, as compared to non-treated control plants. These results indicated that the expression of foreign gene in transgenic plants could be affected by the environmental stresses. Thus, the performance of transgenic plants cultivated on field conditions may be lower than they are expected.

• Journal of Plant Biotechnology
• /
• v.31 no.4
• /
• pp.261-266
• /
• 2004

This experiment was carried out to confirm the stability of bar gene introduced into petunia plant through Agrobacterium-mediated transformation, in successive generation, or after crossing or back-crossing. Some of different 25 transgenic plants were used in crossing and back-crossing to wild type, or repeated-selfing to T$_4$ generation. On the processing of experiment, it was found that some lines lost their resistant ability to herbicide basta, or showed non-Mendelian segregation mode: produced much more susceptible segregants than resistant plants. Even though there are exceptional cases, which was off from expected, the genetic stability of bar gene introduced could be confirmed strongly, because in almost case, the segregation of resistant and susceptible plants to basta was done under Mendelian-law according to single gene dominant model.

• Korean Journal of Environmental Agriculture
• /
• v.31 no.1
• /
• pp.52-59
• /
• 2012

BACKGROUND: Cultivation of genetically modified(GM) crops rapidly has increased in the global agricultural area. Among those, herbicide resistant GM crops are reported to have occupied 89.3 million hectares in 2010. However, cultivation of GM crops in the field evoked the concern of the possibility of gene transfer from transgenic plant into soil microorganisms. In our present study, we have assessed the effects of herbicide-resistant GM Chinese cabbage on the surrounding soil microbial community. METHODS AND RESULTS: The effects of a herbicide-resistant genetically modified (GM) Chinese cabbage on the soil microbial community in its field of growth were assessed using a conventional culture technique and also culture-independent molecular methods. Three replicate field plots were planted with a single GM and four non-GM Chinese cabbages (these included a non-GM counterpart). The soils around these plants were compared using colony counting, denaturing gradient gel electrophoresis and a species diversity index assessment during the growing periods. The bacterial, fungal and actinomycetes population densities of the GM Chinese cabbage soils were found to be within the range of those of the non-GM Chinese cabbage soils. The DGGE banding patterns of the GM and non-GM soils were also similar, suggesting that the bacterial community structures were stable within a given month and were unaffected by the presence of a GM plant. The similarities of the bacterial species diversity indices were consistent with this finding. CONCLUSION: These results indicate that soil microbial communities are unaffected by the cultivation of herbicide-resistant GM Chinese cabbage within the experimental time frame.

• Korean Journal of Plant Resources
• /
• v.11 no.2
• /
• pp.188-194
• /
• 1998

This experiment was conducted to introduce phosphinothricin acetyl -transferase(PAT) gene, resistant to basta and non-selective herbidide, into tobacco(Nicotiana tabacum cv.BY4). For shoot formation,tobacco leaf disks were placed on the MS medium supplemented with 2.0mg/L BA and 0.1mg/L NAA. In this medium condition, tobacco leaf disces were cocultivated with A. tumefaciens MP90 containing NPT IIand PAT resistant to kanamycin and Basta, respectively. Shoots were obtained in the medium containing antibiotics, and those were transferred to rooting medium supplemented with 0.1mg/L NAA and antibiotics. The plants obtaining roots were transplanted into soil. Phenotype of transgenic tobacco plant was mostly as normal plant. However, about 5% was abnormal plant, which did not set seeds. PCR analysis and southern blot were performed to determine transformation. As the results, it was confirmed that PAT gene was stably integrated into tobacco genome.When herbicide, basta, was sprayed to the plants confirmed by PCR, the transgenic plants showed normal growth, whereas normal plants died. Therefore, the result of this experiment show that tobacco transformation for the resistance to basta, non-selective herbicide, was successful because PAT gene was stably integrated into tobacco.

• Applied Biological Chemistry
• /
• v.37 no.4
• /
• pp.248-254
• /
• 1994

Bromoxynil is an antidicot herbicide widely used on cereal crops and has a short half life in the soil. A bxn gene, encoding a specific nitrilase that converts bromoxynil to its primary metabolite 3,5-dibromo-4-hydroxybenzoic acid, was inserted in plant binary vector pGA482, and then introduced into tobacco and lettuce plants via Agrobacterium mediated leaf-disc transformation method. Transgenic plants with the bxn gene were selected by kanamycin and regenerated to whole plants. The regenerated transgenic plants were determined level of expression of bxn gene by Northern blot analysis. Leaf-disc analysis and pot-assay confirmed that the transgenic tobacco and lettuce plants were resistant to high doses of bromoxynil.

• BMB Reports
• /
• v.31 no.3
• /
• pp.287-295
• /
• 1998

Acetolactate synthase (ALS) is the first common enzyme in the biosynthesis of L-Ieucine, L-isoleucine, and L-valine. The sulfonylurea-resistant ALS gene from Nicotiana tabacum was cloned into the bacterial expression vector pGEX-2T. The resulting recombinant plasmid pGEX-ALS3 was used to transform Escherichia coli strain XL1-Blue, and the mutant tobacco ALS (mALS) was expressed in the bacteria as a protein fused with glutathione S-transferase (GST). The fusion product GST-mALS was purified in a single step on a glutathione-Sepharose column. ALS activities of 0.9-2.5 ${\mu}mol/min/mg$ protein were observed in the GST-mALS, and the Km values for pyruvate, FAD, and TPP were 10.8-24.1, $(1.9-8.9){\times}10^{-3}$, and 0.14-0.38 mM, respectively. The purified GST-mALS was resistant to both the sulfonylurea and the triazolopyrimidine herbicides, and lost its sensitivity to end products, L-valine and L-leucine. For comparision, the tobacco wild-type recombinant ALS fused with GST, GST-wALS, was also characterized with respect to its pyruvate and cofactor bindings. These results suggest that the purified mutant recombinant tobacco ALS was functionally active, that the mutations resulting in herbicide resistance has affected pyruvate and cofactor bindings," and that the two classes of herbicides interact at a common site on the plant ALS.

• Plant Biotechnology Reports
• /
• v.3 no.4
• /
• pp.277-283
• /
• 2009

One of the limitations to conducting maize Agrobacterium-mediated transformation using explants of immature zygotic embryos routinely is the availability of the explants. To produce immature embryos routinely and continuously requires a well-equipped greenhouse and laborious artificial pollination. To overcome this limitation, an Agrobacterium-mediated transformation system using explants of type II embryogenic calli was developed. Once the type II embryogenic calli are produced, they can be subcultured and/or proliferated conveniently. The objectives of this study were to demonstrate a stable Agrobacterium-mediated transformation of maize using explants of type II embryonic calli and to evaluate the efficiency of the protocol in order to develop herbicide-resistant maize. The type II embryogenic calli were inoculated with Agrobacterium tumefaciens strain C58C1 carrying binary vector pTF102, and then were subsequently cultured on the following media: co-cultivation medium for 1 day, delay medium for 7 days, selection medium for $4{\times}14$ days, regeneration medium, and finally on germination medium. The T-DNA of the vector carried two cassettes (Ubi promoter-EPSPs ORF-nos and 35S promoter-bar ORF-nos). The EPSPs conferred resistance to glyphosate and bar conferred resistance to phosphinothricin. The confirmation of stable transformation and the efficiency of transformation was based on the resistance to phosphinothricin indicated by the growth of putative transgenic calli on selection medium amended with $4mg\;1^{-1}$ phosphinothricin, northern blot analysis of bar gene, and leaf painting assay for detection of bar gene-based herbicide resistance. Northern blot analysis and leaf painting assay confirmed the expression of bar transgenes in the $R_1$ generation. The average transformation efficiency was 0.60%. Based on northern blot analysis and leaf painting assay, line 31 was selected as an elite line of maize resistant to herbicide.

• Korean Journal of Plant Tissue Culture
• /
• v.28 no.1
• /
• pp.53-58
• /
• 2001

To develop herbicide-resistant cucumber plants (Cucumis sativus L. cv Green Angle) embryogenic suspension cultures were co-cultured with Agrobacterium tumefaciens strain LBA4404 carrying a disarmed binary vector pGA-bar. The T-DNA region of this binary vector contains the nopalin synthase/neomycin phosphotransferase Ⅱ (npt Ⅱ) chimeric gene for kanamycin resistance and the cauliflower 35S/phosphinothricin acetyltransferase (bar) chimeric gene for phosphinothricin (PPT) resistance, After co-cultivation for 48 h, embryogenic calli were placed on maturation media containing 20 mg/L PPT. Approximately 200 putatively transgenic plantlets were obtained in hormone free media containing 40 mg/L PPT. Northern blot hybridization analysis confirmed the expression of the bar gene that was integrated into the genome of five transgenic plants. Transgenic cucumber plants were grown to maturity. Mature plants in soil showed tolerance to the commercial herbicide (Basta) of PPT at the manufacturer's suggested level (3 mL/L).