• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.1
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• pp.13-18
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• 2000

An efficient method for Agrobacterium-mediated transformation of forage crop alfalfa (Medicago sativa L.) was established using secondary somatic embryogenic calli. Agrobacterium tumefaciens strain EHAlOl and a binary vector pIG121-Hm which has selection markers for kanamycin and hygromycin have been shown to be an efticient materials for alfalfa transformation. The secondary somatic embryogenic calli originated from hypocotyl explants of alfalfa were efficient infection materials for Agrobacterium EHAlOl and normally germinated into plantlets. The introduced gene (GUS) was constitutively expressed in all tissues of transgenic alfalfa with different expression levels. These results indicate that the use of pIG121-Hm vector, Agrobacterium EHAlOl and improved culture system of callus facilitate the transformation of alfalfa. (Key words : Agrobacterium, Alfalfa, Gene transfer, Transformation)

• Molecules and Cells
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• v.39 no.9
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• pp.705-713
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• 2016

The efficiency of Agrobacterium-mediated transformation in plants depends on the virulence of Agrobacterium strains, the plant tissue culture conditions, and the susceptibility of host plants. Understanding the molecular interactions between Agrobacterium and host plant cells is crucial when manipulating the susceptibility of recalcitrant crop plants and protecting orchard trees from crown gall disease. It was discovered that Arabidopsis voltage-dependent anion channel 1 (atvdac1) mutant has drastic effects on Agrobacterium-mediated tumorigenesis and growth developmental phenotypes, and that these effects are dependent on a Ws-0 genetic background. Genetic complementation of Arabidopsis vdac1 mutants and yeast porin1-deficient strain with members of the AtVDAC gene family revealed that AtVDAC1 is required for Agrobacterium-mediated transformation, and there is weak functional redundancy between AtVDAC1 and AtVDAC3, which is independent of porin activity. Furthermore, atvdac1 mutants were deficient in transient and stable transformation by Agrobacterium, suggesting that AtVDAC1 is involved in the early stages of Agrobacterium infection prior to transferred-DNA (T-DNA) integration. Transgenic plants overexpressing AtVDAC1 not only complemented the phenotypes of the atvdac1 mutant, but also showed high efficiency of transient T-DNA gene expression; however, the efficiency of stable transformation was not affected. Moreover, the effect of phytohormone treatment on competence to Agrobacterium was compromised in atvdac1 mutants. These data indicate that AtVDAC1 regulates the competence of Arabidopsis to Agrobacterium infection.

• Journal of Forest and Environmental Science
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• v.25 no.3
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• pp.195-204
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• 2009

Agrobacterium-mediated genetic transformation has been widely used for the production of genetically modified transgenic plants to obtain specific desired traits. Most of the molecular mechanisms that underlie the transformation steps have been well elucidated over the years. However, a few steps, such as nuclear targeting, T-DNA integration, and Agrobacterium-plant proteins involved remain largely obscure and are still under extensive studies. This review describes the major steps involved in the molecular mechanism of Agrobacterium-mediated transformation and provides insight in the recent developments in studies on the Agrobacterium-mediated genetic transformation system. Some factors affecting the transformation efficiency are also briefly discussed.

• Korean Journal of Plant Tissue Culture
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• v.27 no.5
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• pp.387-393
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• 2000

The process by which Agrobacterium tumefaciens genetically transforms plants involves a complex series of reactions communicated between the pathogen and the plants. To identify plant factors involved in agrobacterium-mediated plant transformation, a large number of T-DNA inserted Arabidopsis thaliana mutant lines were investigated for susceptibility to Agrobacterium infection by using an in vitro root inoculation assay. Based on the phenotype of tumorigenesis, twelve T-DNA inserted Arabidopsis mutants(rat) that were resistant to Agrobacterium transformation were found. Three mutants, rat1, rat3, and rat4 were characterized in detail. They showed low transient GUS activity and very low stable transformation efficiency compared to the wild-type plant. The resistance phenotype of rat1 and rats resulted from decreased attachment of Agrobacterium tumefaciens to inoculated root explants. They may be deficient in plant actors that are necessary for bacterial attachment to plant cells. The disrupted genes in rat1, rat3, and rat4 mutants were coding a arabinogalactan protein, a likely cell wall protein and a cellulose synthase-like protein, respectively.

• Journal of Plant Biotechnology
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• v.4 no.4
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• pp.135-141
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• 2002

Agrobacterium-mediated transformation has been unsuccessful for monocot plants except for a few important crops such as barley, rice, maize and wheat. We discussed here that a successful transformation of monocots demands certain critical conditions. The requirements for an efficient transformation are a selection of target tissues competent for plant regeneration and Agrobacterium-infection, and various factors promoting Agrobacterium-infection. The factors were divided into two to activate Agrobacterium and to increase plant cell's susceptibility against Agrobacterium. Optimization of these factors significantly increased transformation efficiency of zoysia grass and rice plants. A technical improvement in transformation system for monocots will promote improvement of the breed as well as a study of gene functions in monocots.

• Journal of Life Science
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• v.11 no.4
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• pp.316-320
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• 2001

Sonication tremendously improves the efficiency of Agrobacterium infection by introducing small and uniform fissures and channels throughout the targeted tissue. Using shoot tips of cotton as explants, the effect of sonication treatment and virulence genes in Agrobacterium tumefaciens on transformation efficiency was investigated. The pat gene which encodes resistance to the herbicide, glufosinate, was used as a selectable marker. Transformation efficiency was evaluated on th basis of survival rates of cocultivated shoot tips on selection medium containing 2.5 mg/l gulfosinate-ammonium(ppt) adn 25. mg/l Clavamax. Sonication from 5 to 15 second has a positive effect on shoop tip survival. However, whil virE as well as virG or vir GN54D showed an enhancement in transformation efficiency, virE,. virG resulted in the most significant enhancement. Overall, the combination of additional virG/virE gene and sonication treatment resulted in the most significant increase in transformation efficiency.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.175-181
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• 2011

Effective Agrobacterium-mediated transformation of Trichoderma harzianum could be achieved using the $Al_2O_3$ particles-abraded mycelia pellets. Transformation efficiency, as percents for the number of hygromcin-resistant mycelia pellets out of total pellets tested, was about 20 in average for $Al_2O_3$ experiment. No transformed mycelium was obtained from the intact mycelia pellets. After second round of antibiotics selection, DNA integration of hygromycin resistant gene and the expression of target gene could be confirmed by PCR and RT PCR, respectively. This is the first report of Agrobacterium-mediated T. harzianum transformation.

• Journal of agriculture & life science
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• v.44 no.1
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• pp.9-15
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• 2010

Barley, a monocotyledonous plant, is relatively recalcitrant to the process of Agrobacterium-mediated genetic transformation. In this study, seedlings of six barley cultivars (Keunal-1-Ho, Saessal, Ol, Saechalssal, Seodunchal and Pungsanchalssal) were injured using alkali, oxidizing or reducing agents. They were then transformed using Agrobacterium via vacuum infiltration for the analysis of comparative GUS gene expression. It was determined that chemical injuries causing a slight growth retardation could overall enhance the GUS transformation rate. Hydrogen peroxide was determined to be the most effective.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.141-146
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• 2010

In this study, Agrobacterium-mediated transformation was tested to the mycelium culture of Flamulina velutipes which is very popular as an edible mushroom in Korea. Particularly, aluminum oxide particles were used to generate wounds in F. velutipes mycelia via vigorous shaking prior to agro-infiltration. The result showed that transformants resistant to hygromycin could be obtained only from the mycelia with physical wounds. Gene transfer was verified by genomic DNA PCR. This study suggested a convenient tool to improve Agrobacterium-mediated transformation of F. velutipes.

• Journal of agriculture & life science
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• v.45 no.1
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• pp.119-124
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• 2011

Trichoderma spp. are very important as being a major source for the industrial production of various secreting enzymes in the field of white biotechnology. In this work, Agrobacterium-mediated transformation (AMT) was studied using Trichoderma sp. KACC 40541 which has high activities of amylase, pectinase, cellobiohydrolase and xylanase. In principal, optimized NaOH treatment, prior to Agrobacterium infection, to the mycelium was determined to be very effective for AMT.