• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.53-56
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• 2001

Barley Yellow Dwarf Virus (BYDV), an aphid-borne luteovirus, is a major plant pathogenic disease causing a huge economic loss in the grain production of a wide range of Gramineae species throughout the world. It has been recently reported that BYDV also occurred frequently in wheat field of Korea. Here, we performed to develop the detection and classification methods of BYDV strains that were accomplished by reverse transcription-polymerase chain reaction (RT-PCR). Since there are high variations among BYDV strains, three pairs of primers were designed to detect BYDV strains such as PAV (Vic-PAV and CN-PAV) and MAV (primer A) simultaneously, specifically Vic-PAV(primer B), and MAV (primer C) based on the genomic RNA sequences of BYDV strains previously published. The validity of the primers was confirmed using several BYDV strains obtained from CIMMYT. Though three BYDV strains were able to be detected using primer A, PCR products were not distinguished between two PAV strains. It was possible to separate them with a restriction enzyme, EcoRI, whose restriction site was present in the amplified DNA fragment from Vic-PAV, but not from CN-PAV.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.121-121
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• 2003

Expressed sequence tags (EST) are help to quickly identify functions of expressed genes and to understand the complexity of gene expression. To assist genetic study of the root development in Panax ginseng, which is one of the most important medicinal plant, expressed sequence tags (EST) analysis was carried out. We constructed a CDNA library using the 4-year Chunpoon root. Partial sequences were obtained from 3,841 clone. The ESTs could be clustered into 2,056 (64%) non-redundant groups. Similarity search of the non-redundant ESTs against public non-redundant databases of both protein and DNA indicated that 1,498 groups show similarity to genes of known function. These ESTs clones were divided into eighteen categories depending upon gene function. The most abundant transcripts were major latex protein (41), ribonuclease 2 (36), metallothionein 2(35). Our extensive EST analysis of genes expressed in 4-year Chunpoong root not only contributes to the understanding of the dynamics of genome expression patterns in root organ development but also adds data to the repertoire of all genomic genes.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.235-248
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• 2023

Orchidaceae species account for one-tenth of all angiosperms including more than 30,000 species having significant ecological, evolutionary, and economic importance. Despite Orchidaceae being one of the largest families among flowering plants, crucial cytogenetic information for studying species diversification, inferring phylogenetic relationships, and designing efficient breeding strategies is lacking, except for 10% or less of orchid species cases involving mostly chromosome number or karyotype analysis. Also, only approximately 1.5% of the identified orchid species from less than a hundred genera have genome size data that provide crucial information for breeders and molecular geneticists. Various molecular cytogenetic techniques, such as fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH), have been developed for determining ploidy levels, analyzing karyotypes, and evaluating hybridity, in several ornamental crops including orchids. The estimation of genome size and the determination of nuclear DNA content using flow cytometry have also been employed in some Orchidaceae subfamilies. These different techniques have played an important role in supplementing beneficial knowledge for effective plant breeding programs and other related plant research. This review focused on orchid breeding summarizes the status of current cytogenetic tools in terms of background, advancements, different techniques, significant findings, and research challenges. Principal roles and applications of cytogenetics in orchid breeding as well as different ploidy level determination methods crucial for breeding are also discussed.

• Korean Journal of Plant Tissue Culture
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• v.24 no.1
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• pp.1-35
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• 1997

Fertilized egg, by successive cell divisions, differentiates into different tissues and organs with various structures and functions. Different cells and tissues contain different proteins, products of selective gene expression. Not all the genes in any genomes are equally active, temporal and spatial gene expression being the general rule. Present paper attempts to review the tanscriptional mechanisms or the initiations of transcription from several angles. In some of the organisms the genes in the process of transcription or the genes in the inactive state can be seen under the light microscope. Some bands of Drosophila polytene chromosomes may exhibit a swollen or puff appearance under certain conditions. A puff, unfolded or decondensed form of chromomere, represents sets of intense transcriptional activity or RNA synthesis. The heterochromatic X chromosome whose genes remain inactive in the female mammals can be visualized as a dark staining structure called Barr body, Configuration of chromatin differs between transcribed and nontranscribed chromatin. Modification to the chromatin facilitates RNA synthesis. The movement of large polymerase molecule along the DNA would probably be facilitated if some modifications of the chromatin configuration is effected. Methylation of cytosines in CG sequences is associated with inactive genes. Methylation can play a role in determination of mammalian cells during embryogenesis. Demethylation is necessary for the gene to be expressed during development A histone modification that is also known to be correlated with transcriptional capacity of chromatin is acetylation of the lysine residues of the core histones. Chromatin containing a high level of histone acetylation is very sensitive to DNase 1. For the transcription to occur TBP must first bind to the TATA box. Another TF, TF IIB, then binds to the promoter-TBP complex, facilitating the access of RNA polymerase to the transcription initiation site. As recently as eight years ago researchers assumed that histones were irrelevant to the regulation of gene expression. Histones combine with the DNA to form nucleosome of the chromatin. Histones are vital participant in gene regulation. Histone and basal factors compete for access to TATA box. When DNA is exposed to basal factors before histones are introduced, the basal factors assemble on TATA boxes preventing the access of histones, allowing transcription to occur, for transcription to begin, activator protein at the upstream activation sequence or enhancer must interact with the tail of histone H4 at TATA box and cause the histone role particle to dissociate from the TATA box leading to partial breakup of the histone core particle and allowing the basal factors to bind to the TATA box. New concept of genomic flux in contrast to the old concept of static genome has been developed based on the powerful new molecular techniques. Genomic changes such as repetitive DNAs and transposable elements, it is assumed but not yet proved, may affect some of the developmental patterns that characterize particular cells, tissues, organs, and organisms. In the last decade or so remarkable achievement have been made in the researches of the structures and functions of TFs and the specific target sequences located in promoters or enhancers where these TFs bind. TFs have independent domains that bind DNA and that activate transcription. DNA binding domain of TFs serves to bring the protein into the right location. There are many types of DNA binding domains. Common types of motifs can be found that are responsible for binding to DNA. The motifs are usually quite short and comprise only a small part of the protein structure. Steroid receptors have domains for hormone binding, DNA binding, and activating transcription. The zinc finger motif comprises a DNA binding domain. Leucine zipper consist of a stretch of amino acids with a leucine residue in every seventh position Two proteins form a dimer because they interact by means of leucine zippers on similar α-helical domain. This positions their DNA binding basic domains for interaction with the two halves of a DNA sequence with dyad symmetry of TGACTCA, ACTGAGT.

• Journal of Plant Biotechnology
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• v.34 no.3
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• pp.173-180
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• 2007

The full-length cDNA of LeAPR1 encoded a protein of 461 amino acid residues, which contained homology with phosphoadenosine phosphosulphate reductase (PAPS reductase) in N-terminal and an adenylylsulfate reductase in N-term and C-terminal. Analysis of the deduced amino acid sequence of LeAPR1 revealed that it shares high sequence identity with potato StAPR (96% identity)(Gene bank accession no. CDC44841). We found that multiple copies of LeAPR1 gene are present in the tomato genome through southern blot using genomic DNA was digested with 3 different restriction enzymes. The expression of LeAPR1 was also examined in various organs and its expression was also detected at high levels in roots and stems. Only high amounts of LeAPR1 transcripts were detected at high transcripts in the leaves at time 0, and then reduced as the plant stressed by the NaCl and abscisic acid (ABA). After 24h treatment of NaCl and ABA were showed increasing patterns of LeAPR1 gene. Time course of LeAPR1 gene expression was examined under oxidative stresses from metyl viologen (MV) and hydrogen peroxide ($H_2O_2$). In the presence of 10 mM $H_2O_2$ and $50\;{\mu}M$ MV, the levels of LeAPR1 transcript in leaves decreased after 1 h, and then increased strongly, peaked at 24 h. Our results indicated that LeAPR1 may play a role function of circadian regulation involved in abiotic stresses signaling pathways.

• Ocean and Polar Research
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• v.38 no.3
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• pp.185-193
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• 2016

In this study, antioxidative potentials of the crude extract and its four solvent fractions from the Arctic terrestrial plant Ranunculus heperporeus were evaluated by using four different activity tests, including the inhibition of intracellular reactive oxygen species (ROS) and lipid peroxidation in Raw 264.7 cells as well as determining the extent of both the scavenging of peroxynitrite ($ONOO^-$) and the oxidative damage of genomic DNA purified from Raw 264.7 cells. Based on a comparative analysis, n-BuOH, and 85% aq.MeOH solvent fractions showed good scavenging effects on the production of intracellcular ROS and inhibited membrane lipid peroxidation and DNA oxidation. In addition, n-BuOH and 85% aq.MeOH fractions exhibited good scavenging effects on both authentic peroxynitrite and one generated from SIN-1. Among the samples tested, the n-BuOH fraction revealed the strongest antioxidant effect.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.191-195
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• 2004

Arabidopsis NDPK2 (AtNDPK2) is a key singaling component that regulate cellular redox state and known to enhance multiple stress tolerance when over-expressed in Arabidopsis plant (Moon et al. 2003). In order to develop transgenic potato plants with enhanced tolerance to multiple stresses, we placed an AtNDPK2 cDNA under the control of a stress-inducible SWPA2 promoter or enhanced CaMV 35S promoter. Transgenic potato plants (cv. Superior and Atlantic) were generated using an Agrobacterium-mediated transformation system and selected on MS medium containing 100 mg/L kanamycin. Genomic Southern blot analysis confirmed the incorporation of AtNDPK2 cDNA into the potato genome. When potato leaf discs were treated with methyl viologen (MV) at 10 $\mu$M, transgenic plants showed higher tolerance to MV than non-transgenic or vector-transformed plants. The NDPK2 transgenic potato plants will be further used for analysis of stress-tolerance to multiple environmental stresses.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.149-155
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• 1995

The coat protein (CP) gene was cloned from RNA genome of the Cucumber Mosaic Virus strain ABI (CMV-ABI) isolated in Korea. The comparisons of the nucleotide sequence of the cloned CP gene and its deduced amino acid sequences with other CP genes revealed that the CMV-ABI belongs to subgroup I (type I), CMV-ABI developed the typical mosaic symptom in infected plants. Tobacco plants (Samsun and NC82) were transformed by leaf-disc transformation via Agrobacterium, temefaciens LB4404 harboring pVCP, witch CMV-ABI CP gene was inserted into the pBI121, and a number of mature transgenic tobacco plants were developed. Southern and PCR analysis of genomic DNA from the transgenic plants showed that the CP gene was integrated into the genomes of the most of the transgenic plant. Result of the segregation patterns of resistance in T1 seedlings of the plants to kanamycin showed that the transgenic plants containing l,2 and 3 copies of CP gene were50%, 39% and 11% of the total transgenic plants, respectively.

• Korean Journal of Plant Tissue Culture
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• v.21 no.5
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• pp.315-318
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• 1994

To obtain transformed plants, we cocultured cotyledonary explants of Codonopsis lanceolata with Agrobacterium tumefaciens LBA4404, a disamed strain harboring a binary vector pBI121 carrying the CaMV35S promoter-$\beta$-glucuronidase (GUS) gene fusion used as a reporter gene and NOS promoter-neomycin phosphotransferase gene as a positive selection marker in MS liquid medium with 1mg/L BA. After 48 h of culture, explants were transferred onto MS solid medium with Img/L BA, 250mg/L carbenicillin, and 100mg/L kanamycin sulfate and cultured in the dark. Numerous adventitious buds formed on the cut edges of the explants after 2 weeks of culture. When subjected to GUS histochemical assay buds showed a positive response at a frequency of 15%. Explants formed adventitious shoot at a frequency of 56.7%, after 6 weeks of culture. Upon transfer onto the basal medium, most of the shoots were rooted and subsequently the regenerants were transplanted to potting soil. Southern blot analysis confirmed that the GUS gene was incorporated into the genomic DNA of the GUS-positive regenerants.

• Korean Journal of Plant Tissue Culture
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• v.24 no.3
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• pp.167-173
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• 1997

The embryogenic callus (EC), from which somatic embryos could be induced, was compared with nonembryogenic callus(NE) to study the origin and features of totipotent cell in water dropwort (Oenanthe stolonifera DC). To induce and maintain of EC and the NE, meristematic stem and immature floret were inoculated in MS media supplemented with 1 mg/L 2,4-D, and with 2.5 mg/L NAA and 5mg/L BA, respectively, The EC was not induced from the NE even after subculturing in MS medium supplemented with 1 mg/L 2,4-D. Plantlets were not regenerated from the NE in hormone-free medium. In histochemical comparison of the EC with the NE by light microscopy, the EC had smaller cells in size, dense cytoplasm, and more starch granules of cells compared to the NE cells. The cell from the EC, as observed by transmission electron microscopy, had smaller vaculoes, well developed ribosomes, mitochondria, and endoplasmic reticulum, whereas the cells from the NE had larger vacuoles and underdeveloped organelles. In protein pattern from NE, EC and Somatic embryo (SE), as analyzed by SDS polyacrylamide gel electrophoresis, different proteins specific for tissue were observed: 17 and 28 KD for NE, 50, 52, 57, 66, 68 KD for EC and 20 KD for SE. DNA polymorphism was also observed between EC and NE as analyzed by RAPD (randomly amplified polymorphic DNA) method. The origin of totipotent stem cell and the relationship between irreversible genomic change arose in differentiation and the loss of totipotency in plant were discussed.