• Korean Journal of Microbiology
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• v.25 no.3
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• pp.173-179
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• 1987

Ti plasmids were isolated from three strains of Agrobacterium tumefaciens in Korea and their types and molecular weights were determined. All of these are octopine-type and their molecular weights are 44Kb (pTi 12), 180Kb (pTi 14) and 172Kb (pti 49), respectively. In order to construct physical map of pTi 12, pTi 12 was digested with restriction endonucleases Sma I and Hind III. Sma I degestion of pTi 12 produce 8 fragments and Hind III produced 10 fragments. Physical arrangements of these fragments was determined by Southern hybridization techniques.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.137-142
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• 1997

In order to elucidate the optimum medium on the growth and tropane alkaloid production of hairy root, hairy root were induced by inoculating leaf and stem of Datura stramonium var. tatula Torr. with Agrobacterium spp. Both Agrobacterium tumefaciens $\textrm{A}_{4}$ T and A, rhizogenes ATCC 15834 among tested strains were effective on hairy root formation. Among 23 clones selected in SH (Schenk and Hildebrandt, 1972) liquid medium, DTLA9 clone was shown fast growth of hairy root and DTLE6 clone was shown high level production of tropane alkaloids. When both DTLA9 and DTLE6 clones were cultured in the GD (Gresshoff and Doy, 1972) medium, alkaloid production was higher than in 8 tested media. It was elucidated that optimum medium for root proliferation and for tropane alkaloid production is SH, GD medium, respectively.

• Journal of Plant Biotechnology
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• v.38 no.3
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• pp.198-202
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• 2011

Agrobacterium tumefaciens-mediated cotyledonary-node explants transformation was used to produce transgenic cucumber. Cotyledonary-node explants of cucumber (Cucumis sativus L. cv., Eunsung) were co-cultivated with Agrobacterium strains (EHA101) containing the binary vector (pPZP211) carrying with CaMV 35S promoter-nptII gene as selectable marker gene and 35S promoter-DQ gene (unpublished data) as target gene. The average of transformation efficiency (4.01%) was obtained from three times experiments and the maximum efficiency was shown at 5.97%. A total of 9 putative transgenic plants resistant to paromomycin were produced from the cultures of cotyledonary-node explants on selection medium. Among them, 6 transgenic plants showed that the nptII gene integrated into each genome of cucumber by Southern blot analysis.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1994.06a
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• pp.11-26
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• 1994

Crown gall of stonefruit and nut trees is one of the very few plant diseases subject to efficient biological control. The disease is caused by the soil-inhabiting bacteria Agrobacterium tumefaciens and Agrobacterium rhizogenes and the original control organism was a non-pathogenic isolate of A. rhizogenes strain K84. Control is achieved by dipping planting material in a cell suspension of strain K84 which specifically inhibits pathogenic strains containing a nopaline Ti plasmid. Because the agrocin 84-encoding plasmid (pAgK84) is conjugative, it can be transmitted from the control strain to pathogenic strains which, as a result, become immune to agrocin 84 and cannot be controlled. To prevent this happening, the transfer genes on pAgK84 were located and then largely eliminated by recombinant DNA technology. The resulting construct, strain K1026, is transfer deficient but controls crown gall just as effectively as does strain K84. Field data from Spain confirm that pAgK84 can transfer to pathogenic recipients from strain K84 but not from strain K1026. The latter has been registered in Australia as a pesticide and is the first genetically engineered organism in the world to be released fro commercial use. It is recommended as a replacement for strain K84 to prevent a breakdown in the effectiveness of biological control of crown gall. Several reports indicate that both strains K84 and K1026 sometimes control crown gall pathogens that are resistant to agrocin 84. A possible reason for this is that both strains produce a second antibiotic called 434 which inhibits growth of nearly all isolates of A. rhizogenes, both pathogens and non-pathogens. Crown gall of grapevine is caused by another species, Agrobacterium vitis. It is resistant to agrocin 84 and cannot be controlled by strains K84 or K1026. It is different from other crown gall pathogens in several characteristics, including the fact that, although a rhizosphere coloniser, its also lives systemically in the vascular tissue of grapevine. Pathogen free propagating material can be obtained from tissue culture or, less surely, by heat therapy of dormant cuttings. A number of laboratories are searching for a biocontrol strain that will prevent, or at least delay, reinfection. A non-pathogenic A. vitis strain F/25 from South Africa looks very promising in this regard.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.193-197
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• 1987

Associative heterotrophic nitrogen fixing bacteria were identified by immunodiffusion method in the histosphere of Planta-ginaceae, Caryophllaceae, Gramineae, and two types of rice cultivars. Twenty four strains associative heterotrophic bacteria with high ARA (more than 10nmole/tube/hr) were isolated from the histosphere of grasses and rice.* Those strains were related with 8 species of Azospirillum, 11 species of Pseudomonas, 2 species of Klebsiella and 2 species of Agrobacterium. Among them Azospirillum sp. and Pseudomonas sp. were predominant in histosphere of grasses and rice cultivars. From the histosphere of Oryza sativa, and Sagina maxima, the strains of Azospirillum, Pseudomonas, Klebsiella, and Agrobacter were identified while Pseudomonas was identified from Ischaemum anthephoroides, Plantago lanceolata, Miscanthus sacchuriflorum, and only Azospirillum was identified from Zoisia sinica, respectively. Associative nitrogen fixing heterotrophic bacteria were more abundant in the histosphere of Oryza sativa and Sagina maxima than that of other grasses grown in saline and reclaimed saline paddy soil.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.53-53
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• 2015

Agrobacterium tumefaciens-mediated transformation(ATMT) of Flammulina velutipes was used to produce a diverse number of transformants to discover the functions of gene that is vital for its variation color, spore pattern and cellulolytic activity. Futhermore, the transformant pool will be used as a good genetic resource for studying gene functions. Agrobacterium-mediated transformation was conducted in order to generate intentional mutants of F. velutipes strain KACC42777. Then Agrobacterium tumefaciens AGL-1 harboring pBGgHg was transformed into F. velutipes. This method is use to determine the functional gene of F. velutipes. Inverse PCR was used to insert T-DNA into the tagged chromosomal DNA segments and conducting sequence analysis of the F. velutipes. But this experiment had trouble in diverse morphological mutants because of dikaryotic nature of mushroom. It needed to make monokaryotic fruiting varients which introduced genes of compatible mating types. In this study, next generation sequencing data was generated from 28 strains of Flammulina velutipes with different phenotypes using Illumina Hiseq platform. Filtered short reads were initially aligned to the reference genome (KACC42780) to construct a SNP matrix. And then we built a phylogenetic tree based on the validated SNPs. The inferred tree represented that white- and brown- fruitbody forming strains were generally separated although three brown strains, 4103, 4028, and 4195, were grouped with white ones. This topological relationship was consistently reappeared even when we used randomly selected SNPs. Group I containing 4062, 4148, and 4195 strains and group II containing 4188, 4190, and 4194 strains formed early-divergent lineages with robust nodal supports, suggesting that they are independent groups from the members in main clades. To elucidate the distinction between white-fruitbody forming strains isolated from Korea and Japan, phylogenetic analysis was performed using their SNP data with group I members as outgroup. However, no significant genetic variation was noticed in this study. A total of 28 strains of Flammulina velutipes were analyzed to identify the genomic regions responsible for producing white-fruiting body. NGS data was yielded by using Illumina Hiseq platform. Short reads were filtered by quality score and read length were mapped on the reference genome (KACC42780). Between the white- and brown fruitbody forming strains. There is a high possibility that SNPs can be detected among the white strains as homozygous because white phenotype is recessive in F. velutipes. Thus, we constructed SNP matrix within 8 white strains. SNPs discovered between mono3 and mono19, the parental monokaryotic strains of 4210 strain (white), were excluded from the candidate. If the genotypes of SNPs detected between white and brown strains were identical with those in mono3 and mono19 strains, they were included in candidate as a priority. As a result, if more than 5 candidates SNPs were localized in single gene, we regarded as they are possibly related to the white color. In F. velutipes genome, chr01, chr04, chr07,chr11 regions were identified to be associated with white fruitbody forming. White and Brown Fruitbody strains can be used as an identification marker for F. veluipes. We can develop some molecular markers to identify colored strains and discriminate national white varieties against Japanese ones.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.49-56
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• 2006

Gerber (Gerbera hybrida) is a valuable ornamental species grown as a potted plant and cut flowers. However, genetic variability within the gerbera genus is very limited. So it is absolutely needed to introduce and widen genetic resources into gerbera lines by genetic transformation. For the purpose, 18 Korean gerbera lines were screened to establish Agrobacterium-mediated genetic transformation procedure. In an experiment to select Korean gerbera lines which are amenable to Agrobacterium-inoculation, 12 lines turned out to be positive in Agrobacterium-inoculation. More callus were produced from BA 2ppm, Zeatin 2ppm, IAA 0.2ppm in pre-culture and regeneration medium (2X media) but there was no difference in the frequency of GUS expression rate. In another experiment to find out optimal condition for highly efficient Agrobacterium-inoculation, petiole and leaf explants have been treated with four different pre-culture periods, two different co-culture periods and two different Agrobacterium strains. As a result, high GUS expression has been showed from petiole and leaf explants treated no pre-culture period with LBA4404 Agrobacterium tumerfaciens, 5 day co-culture period and dipping treatment.

• Journal of Plant Biotechnology
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• v.34 no.2
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• pp.139-144
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• 2007

Hypocotyl explants of Chinese cabbage (cvs. "Jeong Sang") produced transgenic calli on callus induction medium (MS salt, B5 vitamin, 5 mg/L acetosyringone, 1 mg/L 2,4-D, 3% sucrose, 400 mg/L cefotaxime, 100 mg/L paromomycin, pH 5.8) after cocultivation with strains of Agrobacterium tumefaciens (EHA101, LBA4404, GV3101) harboring the pPTN290 containing paromomycin-resistance gene as a selectable marker, and then they transferred to root induction medium (1/2MS salt, MS vitamins, 2% sucrose, 100 mg/L paromomycin, 100 mg/L cefotaxime, pH 5.8) and shoot induction medium (MS salt, B5 vitamin, 4 mg/L $AgNO_3$, 4 mg/L 6-benzyladenine, 3 mg/L alpha-naphthaleneacetic acid, 100 mg/L paromomycin, 100 mg/L cefotaxime, 3% sucrose, pH 5.8) in order. There was a significant difference in the frequency of transgenic calli depending on Agrobacterium strains. In particular, the highest frequency (6.1%) of transgenic calli was obtained from the hypocotyls cocultivated with EHA101 strains. Also, the frequency (%) of transgenic root and plants from each transgenic callus clone were obtained with 60.7% and 38.2% in EHA101, with 8.3% and 0% in LBA4404, with 20.5% and 85.7% in GV3101 strains, respectively. They were grown to maturity in a greenhouse and normally produced $T_2$ seeds. GUS histochemical assay for progeny ($T_2$) revealed that the transgenes was expressed in the plant genome, and progeny analysis from 7 independent transgenic events demonstrated that the transformants transmitted the transgene as a single or multiple functional locus.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.1000-1006
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• 2011

We examined the effects of various phenolic compounds, Ti plasmids(octopine, nopaline) and A. tumefaciens on the vir gene expression. Nine phenolic compounds were tested using 3 types of Ti plasmid and 3 strains of A. tumefaciens on the vir gene expression. It was also investigated how the levels of vir gene expression could be related to specific phenolic compounds. Six phenolic compounds as 4-hydroxyacetophenone, phenol, catechol, resorcinol, acetosyringone and vanillin had exhibited a strong effect on the vir gene expression of A. tumefaciens MW107 containing nopaline Ti plasmid. The vir genes of A. tumefaciens MW105 and MW108 containing octopine Ti plasmids were remarkably stimulated only by acetosyringone. Thus, it appeared that the vir gene inducing abilities were differed by the kinds of phenolic compounds, A. tumefaciens and Ti plasmids.

• Journal of Plant Biology
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• v.34 no.4
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• pp.289-296
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• 1991

Cultures of hairy root induced from ginseng(Panax C.A. Meyer) transformed with Agrobacterium rhizogenes (strain A4, ATCC 15834) were established and morphologically two different hairy root strains (HB1, HB2) were obtained. To determine the optimum growth rate, the hairy root (HB2) was cultured in various liquid medium supplemented with or without plant growth hormone. The growth rate of hairy root cultured on MS medium was 1.3-3.1 times higher than those cultured on other media, and the optimum sucrose concentration and pH were 3-6%, 5.5-6.5, respectively. Also, the growth rate of hairy root was increased when 0.02 M ammonium nitrate, 1.2 mM potassium phosphate (monobasic) and 0.5 mg/l IBA were supplied to liquid medium. The saponin patterns and contents of hairy root (HB2) were determined by TLC and HPLC. The crude saponin contents were 4.67% and the total saponin contents were 1.0%, on dry weight basis.