• Korean Journal of Microbiology
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• v.27 no.3
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• pp.310-315
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• 1989

Tabtoxin produced in Pseudomonas syringae pv. tabace irreversibly inhibits its known physiological target, glutamine synthetase so that causes wildfire disease on leaves of host plant. In this study, we examined a rapid and sensitive microbiological method for tabtoxin assay in several media. In minimal A agar medium nd minimal glucose agar medium, growth inhibition zone of Agrobacterium tumefaciens was larger than that of other indicator strain. However, mostly, growth inhibition zone of indicator strains on the minimal glucose agar medium was smaller than that of on the miniaml A agar medium. In complex agar medium, growth inhibithiton zone was not observed in all the tested indicator strains. Pseudomonas syringae pv. tabaci produced more tabtoxin according to the incubation time. When glutamine was added to the minimal glucose agar medium, growth inhkbition zone of Agrobacterium tumefaciens was reduced.

• Microbiology and Biotechnology Letters
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• v.38 no.2
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• pp.216-221
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• 2010

This study shows an application of microbiologically induced carbonate precipitate for strength improvement and crack remediation of cement-sand mortar. Seven calcium carbonate-forming bacteria (CFB) were isolated from Dok-do and partially identified by DNA sequence analysis of the 16s rRNA gene. Crystal aggregates were apparent around the bacterial colonies grown on an agar medium. These strains showed strain specific $CaCO_3$ precipitation on urea-$CaCl_2$ medium. Among 7 isolates, Arthrobacter nicotinovorans KNUC601, Microbacterium resistens KNUC602, Agrobacterium tumefaciens KNUC603, Exiguobacterium acetylicum KNUC604, and Bacillus thuringiensis KNUC606 showed a repairing of artificial forced cracks in cement-sand mortar. Compressive strength of cement-sand mortar consolidated with Stenotrophomonas maltophilia KNUC605 was increased around 14.07% compared with that of negative control.

• Research in Plant Disease
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• v.12 no.2
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• pp.75-80
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• 2006

Crown gall on rose was observed in greenhouse during year 2003-2005. The disease incidence was up to 28.3% and the disease was the severer in hydrophonics culture than that in soil. The typical gall symptom occurred mainly on the root and crown resulting in poor foliage, stunting, and fewer blossoms. Sixty-three rose cultivars were inoculated with Agrobacterium. tumefaciens isolated from rose crown gall, to evaluate rose cultivar-specific resistance. The size of galls from inoculated rose stems was measured in a greenhouse test. Tumors formed in almost varieties of rose inoculated. Based on the frequency of tumor occurrence and weight of galls formed on the stem of rose, it was shown that 'Little Marble', 'Golden Gate' and 'Rosa Rox-ette' were extremely susceptible to crown gall. Some varieties such as 'Little Silver' appeared to be resistant to the crown gall.

• Molecules and Cells
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• v.28 no.5
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• pp.447-453
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• 2009

The quorum sensing (QS) inhibitors that antagonize TraR, a receptor protein for N-3-oxo-octanoyl-L-homoserine lactones (3-oxo-C8-HSL), a QS signal of Agrobacterium tumefaciens were developed. The structural analogues of 3-oxo-C8-HSL were designed by in silico molecular modeling using SYBYL packages, and synthesized by the solid phase organic synthesis (SPOS) method, where the carboxamide bond of 3-oxo-C8-HSL was replaced with a nicotinamide or a sulfonamide bond to make derivatives of N-nicotinyl-L-homoserine lactones or N-sulfonyl-L-homoserine lactones. The in vivo inhibitory activities of these compounds against QS signaling were assayed using reporter systems and compared with the estimated binding energies from the modeling study. This comparison showed fairly good correlation, suggesting that the in silico interpretation of ligand-receptor structures can be a valuable tool for the pre-design of better competitive inhibitors. In addition, these inhibitors also showed anti-biofilm activities against Pseudomonas aeruginosa.

• Journal of Plant Biotechnology
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• v.50
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• pp.63-69
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• 2023

This study includes the transformation of genes such as ORE7, the increase of gene expression, and the use of the bar gene as a selectable marker that shows herbicide resistance with Agrobacterium tumefaciens using hypocotyls from the oilseed rape "Youngsan" cultivar. To establish an Agrobacterium transformation system for the production of oilseed rape with a high-yield trait, infection time and co-cultivation period with Agrobacterium were tested. Therefore, when hypocotyls from the oilseed rape "Youngsan" cultivar were infected with Agrobacterium for 20 min and co-cultivated for 3 days, approximately 32-36 putatively transformed hypocotyls with shoots including roots survived from 100 inoculated hypocotyls after 4 weeks of transformation on a selection medium containing 20 mg/L of phosphinothricin (PPT) as a selectable agent. Additionally, a PCR assay was performed to confirm the insertion of target genes and showed the presence of the ORE7 gene as a high-yielding trait and the bar gene as a selectable marker. Treatment with 0.5% (v/v) Basta solution as a selectable agent for 6 days with leaves from transformed oilseed rape expressed the bar gene. Therefore, this study can contribute to the development of special oilseed rapes containing agriculturally useful traits such as herbicide resistance, drought tolerance, high yielding traits, and high oleic acid content.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.308-314
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• 2011

Efficient transformation and regeneration methods are a priority for successful application of genetic engineering to vegetative propagated plants such as grape. In this study, methods for Agrobacterium tumefaciens-mediated transformation and plant regeneration of grapevine (Vitis vinifera) were evaluated. Tamnara, Heukgoosul, Heukbosek, Rizamat were co-cultivated with Agrobacterium strains, LBA4404 containing the vector pBI121 carrying with CaMV 35S promoter, GUS gene as reporter gene and resistance to kanamycin as selective agent. Seven percent of the maximum regeneration frequency was obtained from co-cultivated with explants from Rizamat with LBA4404 strain on selection medium with kanamycin. The addition of acetosyringone, 200 ${\mu}m$ in virulence induction step was a key factor for successful GUS reporter gene expression in grapevine transformation. Transgenic plants showed resistance to kanamycin and the GUS positive response in leaf ($T_0$) stem ($T_0$) and petiole ($T_0$).

• Korean Journal of Medicinal Crop Science
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• v.11 no.4
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• pp.289-297
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• 2003

Using Agrobacterium-me야ated transformation method the auxin-regulated cotton GST (Gh-5) constructs were used to transform Rehmannia glutinosa L. The PCR analysis was conducted to verify transgenicity. Based on the PCR analysis, there was verified that the 988 bp DNA band had showed in transgenic plant genomes in PCR anaJysis using Gh5-1 and Gh5-2 primers. The effects of cocultivation with Agrobacterium tumefaciens, regeneration and selection conditions on the transformation efficiency of Chinese foxglove (Rehmannia glutinosa L.) were investigated. Factors such as cocultivation period, use of acetosyringone, postcultivation in darkness, and different kanamycin concentrations for selection were assessed. In vitro regeneration, the number of leaves, shoot lengths and numbers on MS medium were superior to on B5 and WPM medium, and the shoot formation rate was highest level of 95% in cultured base part containing leaf stalk. Addition of acetosyringone at concentration of $200{\mu}M$ to cocultivation medium and 3-day of cocultivation improved transformation frequencies. Exposure of explants to darkness for 4 weeks on selection medium resulted in further increased the regeneration frequency of transgenic shoots. In PCR analysis, the amplified fragments of Gh5 gene were detected (988 bp), and GST-expressing transgenic R. glutinosa L. plants had approximately three-fold higher activity in leaf extracts compared with control plant.

• Journal of Life Science
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• v.19 no.3
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• pp.378-383
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• 2009

Agrobacterium tumefaciens-mediated transformation procedure for the phalaenopsis orchid, established by using Protocorm-like bodies (PLBs), was aimed at the introduction of target genes into individuals with divergent genetic backgrounds. PLBs obtained from the axillary bud of a peduncle were maintained on a hyponex medium supplemented with 1 g/l of activated charcoal, 30 g/l of sucrose and 0.1 mg/l thiamine. The multiplication rate of PLBs was about 90% in case of subculture PLBs to be cut transversely into 1/3 part from top position. The PLBs were inoculated with Agrobacterium strain EHA105 harboring both $\beta$-glucuronidase (GUS) and hygromycin-resistant genes for 20 minutes after dipping treatment. Transformation efficiency was the highest with a Agrobacterium culture medium and dipping treatment of O.D. 0.8. Newly induced PLBs were put on selection medium containing 1 mg/l hygromycin for 2 months. Hygromycin-resistant phalaenopsis plants that regenerated after the selection culture of PLBs showed histochemical blue staining due to GUS. Transgene integration of the hygromycin-resistant plants was confirmed by PCR and Southern blot using GUS specific primers and probe.

• Korean Journal of Weed Science
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• v.18 no.3
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• pp.205-213
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• 1998

This experiment was carried out to produce herbicide resistant potatoes hawing only chimeric phosphinothricin acetyltransferase (PAT) genes without using antibiotic selectable marker. The pDY502 vector having only PAT gene was reconstructed for transformation of potato. The reconstructed vector was introduced to Agrobacterium tumefaciens MP90 disarmed, and they were used for potato transformation. Hormonal requirement for plant regeneration from leaves and stem explants of potato was investigated. From this experiment, MS medium treated with IBA 0.1 mg/L + BA 0.5 mg/L was the best for potato regeneration, and the ratio of shoot regeneration was 54% for leaf and 46% for stem in that condition. For transformation, explants of potato leaves and stems were cocultured with A. tumefaciens MP90 containing reconstructed vector harvoring only PAT gene. When the potato explants were placed on various concentrations of bialaphos and all the potato explants were dead on medium with over 5.0mg/L bialaphos. By this selection methods, the explants cocultured with Agrobacterium produced the putative transgenic shoots on medium with 5mg/L bialaphos treatment after 3-4 weeks. Second selection was performed by transferring the shoot tips of putative transgenic to medium containing 20mg/L of bialaphos. The shoot tips grew well on the second selection medium, indicating the production of successful transgenic plants. But normal shoots were dead in same cytotoxic medium. Incorporation of the PAT gene into transgenic potatos were confirmed by PCR analysis of DNA and Southern hybridization. These results show that the PAT gene can serve as a selectable marker and herbicide resistant genes for transformation of potato.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.138-147
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• 2024

Agrobacterium-mediated transformation (AMT) is a method that allows for the stable integration of DNA fragments into the plant genome. Transgenic plants generated through AMT typically exhibit a lower copy number of the transgene compared to those induced by particle bombardment. Furthermore, AMT offers a straightforward and efficient approach for generating transgenic plants. While the transformation efficiency of wheat is comparatively lower than that of other monocot plants such as Rice (Oryza sativa L.) and Maize (Zea mays L.), the cultivars 'Bobwhites' and 'Fielder' are commonly employed for wheat transformation. To date, there have been no reported instances of successful development of transgenic plants using Korean wheat varieties through AMT. This study aims to assess the transformation efficiency of 43 Korean wheat cultivars using the GUS assay, with the goal of identifying suitable Korean wheat cultivars for AMT. The pCAMBIA1301 vector, carrying the β-glucuronidase (GUS) gene, was incorporated into Agrobacterium strain EH105. Following the inoculation of Agrobacterium into immature embryos, GUS assays were conducted 'Saeol', 'Jopum', and 'Jonong' showed 100% (the number of embryos showing GUS spots/the number of embryos used for AMT) among 43 cultivars. In addition, cultivars with more than 70% were 'Saekeumgang', 'Jojung', 'Tapdong', 'Anbaek', 'Dabun', 'Sugang', 'Keumgang', 'Jeokjung', 'Seodun', 'Joeun', 'Dajung', and 'Baekjung'. It seems that the 15 cultivars above showed the possibility of using AMT. On the other hand, 'Yeonbaek', 'Goso', 'Baekgang', and 'Johan' showed less than 20% and GUS spots were not observed in 'Gru', 'Gobun', 'Milseong', and 'Shinmichal-1'. This study explores transient GUS expression in Korean wheat cultivars seven days after AMT. The observed initial high efficiency of transient transformation suggests the potential for subsequent stable transformation efficiency. Korean wheat cultivars demonstrating elevated transient transformation efficiency could serve as promising candidates for the development of stable transgenic wheat.