• 생명과학회지
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• 제22권12호
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• pp.1614-1620
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• 2012

유전자총(Particle bombardment) 방법에 의해 snowdrop lectin (Galanthus nivalis agglutinin; GNA) 유전자가 도입된 해충저항성 형질전환 벼를 개발하였다. GNA 유전자가 도입된 많은 형질전환 식물체가 재분화되었으며, 형질전환 벼의 GNA 유전자의 integration, expression 및 inheritance는 Southern 및 western analysis분석 방법에 의해 증명되었다. 벼 genome 내 도입 유전자 수는 one 혹은 five copies이었다. 형질전환 $R_1$과 $R_2$ 식물체의 GNA 단백질 발현 분석 결과, 함량은 총 단백질 중 0.01%부터 2.0%까지 포함하고 있었다. 형질전환 식물체 중 GNA 과발현 형질전환 벼를 이용한 생물 검정 결과, 대조구와 비교하여 벼의 주요 해충인 벼멸구(Nilaparvata lugens St${\aa}$l)에 저항성을 나타내었다. 위의 실험 결과를 통해, 해충저항성 유전자인 GNA가 도입된 형질전환 벼는 해충의 증식을 억제하는데 이용될 수 있을 것이다.

• Journal of Plant Biotechnology
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• 제30권2호
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• pp.143-149
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• 2003

This experiment was carried out to confirm the stability of bar gene introduced into petunia plant through Agrobacerium-mediated transformation. Twenty-five transgenic plants T$_{0}$ plants, back cross (BC$_1$) populations to wild type and F$_1$plants between different T$_{0}$ plants were prepared, and polymerase chain reaction(PCR), PCR-Southern blot analysis, and field test with 0.1% Basta treatment were done. The results of PCR, PCR-Southern blot hybridization, and field test indicated that NPTII and bar gene introduced into the genome of petuina plants were stably transmitted to their progenies, and conferred the plants resistance to herbicide, Basta.sta.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.90.1-90
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• 2003

Colonization of Pseudomonas chlororaphis O6, a nonpathogenic rhizobacterium, on the roots induced systemic resistance in cucumber plants against tai-get leaf spot, a foliar disease caused by Corynespora cassiicola. A cDNA library was constructed using mRNA extracted from the cucumber leaves 12 h after inoculation with C. cassiicola, which roots had been previously treated with O6. To identify the genes involved in the O6-mediated induced systemic resistance (ISR), we employed a subtractive hybridization method using mRNAs extracted from C cassiicola-inoculated cucumber leaves with and without previous O6 treatment on the plant roots. Differential screening of the cDNA library led to the isolation of 5 distinct genesencoding a GTP-binding protein, a putative senescence-associated protein, a galactinol synthase, a hypersensitive-induced reaction protein, and a putative aquaporin. Expressions of these genes are not induced by O6 colonization alone. Before challenge inoculation, no increase in the gene transcriptions could be detected in previously O6-treated and untreated plants but, upon subsequent inoculation with the pathogenic fungus, transcription levels in O6-treated plants rose significantly faster and stronger than in untreated plants. Therefore, the O6-mediated ISR may be associated with an enhanced capacity for the rapid and effective activation of cellular defense responses which becomes apparent only after challenge inoculation on the distal, untreated plant parts, as suggested by Conrath et al. (2002). This work was supported by a grant R11-2001-092-02006-0 from the Korea Science and Engineering Foundation through the Agricultural Plant Stress Research Center at Chonnam National University.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.917-923
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• 2014

Chondrosarcomas are malignant cartilage-forming tumors of bone which exhibit resistance to both chemotherapy and radiation treatment. miRNAs have been well demonstrated to regulate gene expression and play essential roles in a variety of biological processes, including proliferation, differentiation, migration, cell cycling and apoptosis. In this study, we obtained evidence that miR-100 acts as a tumor suppressor in human chondrosarcomas. Interestingly, cisplatin resistant chondrosarcoma cells exhibit decreased expression of miR-100 compared with parental cells. In addition, we identified mTOR as a direct target of miR-100. Overexpression of miR-100 complementary pairs to the 3' untranslated region (UTR) of mTOR, resulted in sensitization of cisplatin resistant cells to cisplatin. Moreover, recovery of the mTOR pathway by overexpression of S6K desensitized the chondrosarcoma cells to cisplatin, suggesting the miR-100-mediated sensitization to cisplatin dependent on inhibition of mTOR. In summary, the present studies highlight miR-100 as a tumor suppressor in chondrosarcoma contributing to anti-chemoresistance. Overexpression of miR-100 might be exploited as a therapeutic strategy along with cisplatin-based combined chemotherapy for the treatment of clinical chondrosarcoma patients.

• Journal of Microbiology and Biotechnology
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• 제19권3호
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• pp.271-276
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• 2009

Functional gene studies in the cultivated white button mushroom Agaricus bisporus have been constrained by the absence of effective gene-silencing tools. Using two endogenous genes from A. bisporus, we have tested the utility of dsRNA hairpin constructs to mediate downregulation of specific genes. Hairpin constructs for genes encoding orotidine 5'-monophosphate decarboxylase (URA3) and carboxin resistance (CBX) were introduced into A. bisporus using Agrobacteriummediated transfection. Although predicted changes in phenotype were not observed in vitro, quantitative-PCR analyses indicated unambiguously that transcripts in several transformants were substantially reduced compared with the non-transformed controls. Interestingly, some hairpin transformants exhibited increased transcription of target genes. Our observations show that hairpin transgenic sequences can mediate downregulation of A. bisporus endogenous genes and that the technology has the potential to expedite functional genomics of the mushroom.

• 식물병연구
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• 제16권1호
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• pp.10-20
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• 2010

Root-knot nematodes cause billions of dollars in crop losses annually have a broad range of host over 2,000 species of plants. These nematodes are known as obligate, sedentary endo-parasites in a plant host to feed upon to complete their life cycle. To prevent the plant parasitic nematode, methyl bromide was widely applied as a soil fumigant. Other strategies to prevent or control nematodes involve RNAi-mediated suppression, R gene transformation, natural products or chemical treatments, the expression of peptide or proteins in susceptible plants, and others. Over the last decade, the entry in GenBank for Meloidogyne reveals 73,340 ESTs and recently two complete Meloidogyne spp. genomes sequences have simultaneously been presented by two groups. Recent works have demonstrated the effect of RNAi suppression to nematode target genes. These results will provide novel members of genes as a foundation for studies focused on understanding the function of M. incognita nematode genes as well as for the development of novel target genes for parasite control. Thus the successful development of biotechnology-derived plants with nematode resistance will result in large yield benefits for producers as well as environmental benefits and will accelerate the research related to pathogensresistant crops.

• Journal of Plant Biotechnology
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• 제38권4호
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• pp.272-277
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• 2011

Plants expressing Agrobacterium sp. strain CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) are known to be resistant to glyphosate, a potent herbicide that inhibits the activity of the endogenous plant EPSPS. In order to develop herbicide-resistant rice, we prepared transgenic rice plants with CP4 EPSPS gene under the control of CaMV 35S promoter for over-expression. A recombinant plasmid was transformed into rice via Agrobacterium-mediated transformation. A large number of transgenic rice plants were obtained with glyphosate and most of the transformants showed fertile. The integration and expression of CP4 EPSPS gene from regenerated plants was analyzed by Southern and northern blot analysis. The transgenic rice plants had CP4 EPSPS enzyme activity levels more than 15-fold higher than the wild-type plants. EPSPS enzyme activity of transgenic rice plants was also identified by strip-test method. Field trial of transgenic rice plants further confirmed that they can be selectively survived at 100% by spay of glyphosate (Roundup$^{(R)}$) at a regular dose used for conventional rice weed control.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.856-865
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• 2012

We describe the construction and immunobiological properties of a novel whooping cough vaccine candidate, in which the aroQ gene, encoding 3-dehydroquinase, was deleted by insertional inactivation using the kanamycin resistance gene cassette and allelic exchange using a Bordetella suicide vector. The aroQ B. pertussis mutant required supplementation of media to grow but failed to grow on an unsupplemented medium. The aroQ B. pertussis mutant was undetectable in the trachea and lungs of mice at days 6 and 12 post-infection, respectively. Antigen-specific antibody isotypes IgG1 and IgG2a, were produced, and cell-mediated immunity [CMI], using interleukin-2 and interferon-gamma as indirect indicators, was induced in mice vaccinated with the aroQ B. pertussis vaccine candidate, which were substantially enhanced upon second exposure to virulent B. pertussis. Interleukin-12 was also produced in the aroQ B. pertussis-vaccinated mice. On the other hand, neither IgG2a nor CMI-indicator cytokines were produced in DTaP-vaccinated mice, although the CMI-indicator cytokines became detectable post-challenge with virulent B. pertussis. Intranasal immunization with one dose of the aroQ B. pertussis mutant protected vaccinated mice against an intranasal challenge infection, with no pathogen being detected in the lungs of immunized mice by day 7 post-challenge. B. pertussis aroQ thus constitutes a safe, non-reverting, metabolite-deficient vaccine candidate that induces both humoral and cell-mediated immune responses with potential for use as a single-dose vaccine in adolescents and adults, in the first instance, with a view to disrupting the transmission cycle of whooping cough to infants and the community.

• 한국응용곤충학회지
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• 제22권2호
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• pp.52-66
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• 1983

The brown planthopper, N. lugens (Stal), has become a serious pest of rice in tropical Asia during the last decade. At high pest density, its feeding damage causes 'hopperburn' or complete wilting and drying of the rice plant. It also transmits grassy and ragged stunt virus diseases. The estimated losses caused by the pest in tropical Asia exceed $US\$300$ millions. While cultivation of resistant rice varieties has proved to be highly effective against the pest, their long-term stability is threatened because of the evolution of prolific biotypes which can destroy these varieties. At present, identification of biotypes is based principally on the differential reactions of host rice varieties to the pest and on host-mediated behavioral and physiological responses of the pest. Recent findings of morphological differences in adult rostrum, legs, and antennae, body parts that possess receptors for host plant location and discrimination, and cytological differences in N. lugens populations maintained as stock cultures strongly complement other biotype studies. So far, three N. lugens biotypes have been identified in the Philippines. Biotype I can survive on and damage varieties that do not carry and genes for resistance, while Biotype 2 survives on resistant varieties carrying Bph 1 gene and Biotype 3 on varieties carrying gene bph 2. However, none of these biotypes can survive on varieties with genes Bph 3 or bph 4. Several varieties which are resistant in the Philippines are susceptible in India and Sri Lanka as the South Asian biotypes of N. lugens are more virulent than Southeast Asian biotypes. To monitor the pest biotypes in different geographical regions and to identify new sources of resistance, an International Brown Planthopper Nursery has been established in many cooperating countries. The evolution of biotypes is an exceedingly complex process which is governed by the interactions of genetic and biological factors of the pest populations and the genetic makeup of the cultivated varieties. While the strategy for sequential release of varieties with major resistance genes has been fairly successful so far, the monegenic resistance of these varieties makes them vulnerable to the development of the pest biotypes. Therefore, present breeding endeavors envisage utilizing both major and minor resistance genes for effective control of the pest.

• 식물병연구
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• 제25권2호
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• pp.49-61
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• 2019

식물 바이러스는 작물 생산량 손실을 일으키는 주요 병원체 중 하나로, 돌연변이 발생이 빈번하고 치료 약제가 개발되어 있지 않아 방제가 매우 어렵다. 이러한 바이러스병을 방제하기 위한 가장 효과적인 방법은 저항성 품종을 재배하는 것이며, 바이러스 저항성 품종을 개발하기 위해서는 바이러스와 기주 식물 간의 다양한 유전자적 상호작용에 대한 정확한 이해가 필요하다. 열성 저항성은 병원체가 살아가는데 필요한 식물 유전자가 결핍되었을 때 획득되는데, 저항성 유전자(R gene)에 의해 유도되는 우성 저항성에 비해 넓은 범위의 저항성을 발현하고 돌연변이 출현에 쉽게 저항성이 깨지지 않는 특성을 보인다. 현재까지 알려진 바이러스병에 대한 열성 저항성 유전자는 대부분 순행유전학(forward genetics)를 통해 밝혀졌으나, 최근 CRISPR/Cas9 등을 이용한 유전자 교정 기술의 급속한 발전에 힘입어 역유전학(reverse genetics)을 통한 열성 저항성 작물개발의 가능성이 열리고 있다. 이러한 역유전학적 접근을 통한 열성 저항성 작물 개발은 먼저 바이러스 단백질과 상호작용하는 기주 인자를 밝히고 이들간의 상호작용을 억제하도록 하는 기주 인자에 대한 유전자 교정을 통해 이루어 질 수 있다. 본 논문에서는 열성 저항성에 대한 소개와 새로운 열성 저항성 후보 유전 소재 발굴을 위한 기주 인자 연구의 중요성 및 방법을 소개하고, 열성 저항성 작물 개발에 적용할 수 있는 유전자 교정기술의 최신 동향에 관해 정리하였다.