• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.80.1-80
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• 2003

Several plant and microbial genes that could confer disease resistance in transgenic rice plants are being cloned and characterized. We are currently constructing transgenic rice lines that overexpress the gene products, such as a galactinol synthase, a defensin, and a bacterial ACC deaminase. Subtractive hybridization of a rice cDNA library constructed from the Xanthomonas oryzae-infected ice leaves resulted in isolation of many inducible cDNA clones including a elongation factor EF2, a oryzain alpha, a catalase, a aldehyde dehydrogenase, a S-adenosylmethionine synthetase, a caffeic acid O-methyltransferase, a glyceraldehyde-3-phosphate dehydrogenase, a light-regulated protein, nKY transcription factors, and a nucleotide diphosphate kinase. Some genes among those may be useful genetic sources for construction of disease resistant transgenic rice. Full lengths of the rice OsFIERG and a rice oryzain genomic clones were cloned, and serial deletion fragments of the promoter regions of these genes were fused with GUS reporter gene in pCAMBIA1201, respectively. Promoter activities of these constructs will be examined upon various stresses and Pathogen infections to obtain the pathogen specific inducible-promoter. This work was supported by a grant from BioGreen 21 Program, Rural Development Administration, Republic of Korea.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.515-524
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• 2010

The amylose content of starch is a major factor in the texture of cooked cereal grains. Therefore, down-regulation of amylose synthesis is one of the alternative method to improve eating quality of rice. We developed transgenic rice plants designed to suppress granule-bound starch synthase I(GBSSI) gene using RNA interference(RNAi) technology. Transgenic plants with RNAi vector containing the 3'-UTR region of GBSSI showed a lower amylose content in rice endosperm than that of wild-type. The range of amylose content was 5.9~9.0% in the transgenic plants, whereas that of wild-type was 17.7~18.0%. Transgenic rices showed the decrease of short chain and the increase of long chain by analyzing chain length distribution of amylopectin in the endosperm. In the SEM micrographs, we found that compound starch granules in whole grains of the wild-type rice were readily split during fracturing, while the starch granules in RNAi-transgenic lines showed small voluminous, non-angular rounded bodies.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.305-313
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• 2020

Root hair development has the potential to increase crop yields and at the same time to decrease fertilizer use, which will be required in the next 30 years to meet the demand for crop-derived commodities in a world with decreasing available natural resources. Root hair defective six (RHD6) encoding a basic helix-loop-helix transcription factor, is associated with root hair differentiation, and its roles are root hair initiation and elongation. Grass plants, rice and Brachypodium have been used as model plants to study the gene function of the root hair defective six like (RSL) subfamily which is orthologous to AtRHD6. The RSL subfamily has an identical gene function with AtRHD6 which is involved with root hair differentiation as well. Plants with longer root hairs within a species should have an improved Pi uptake efficiency; therefore, we would expect that a plant with a high Pi uptake could contribute to increasing the plant yield. We achieved increased root hair length by manipulating the RSL subfamily genes. It is expected that in these transgenic plants, the long root hairs would be sufficient to improve the Pi uptake and hence improve biomass and yield component (tiller, spikelet number, and spikelet weight) of the plant. Here, we demonstrate that Brachypodium transgenic plants overexpressing the BdRSL subfamily genes have an improved biomass and grain yield. The result of this study could be applied to important crop plants like rice.

• Journal of Life Science
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• v.13 no.1
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• pp.83-89
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• 2003

To investigate the function of chloroplast small heat shock protein (HSP), transgenic tobacco plants (Nicotiana tabacum L, cv. SR-1) that constitutively overexpress the rice chloroplast small HSP (Oshsp26) were generated. Effects of constitutive expression of the Oshsp26 on thermotolerance were investigated with the chlorophyll fluorescence. After 5-min incubation of leaf discs at high temperatures, an increase in the Fo level, indication of separation of LHCII from PSII, was mitigated by constitutive expression of the chloroplast small HSP When tobacco plantlets grown in Petri dishes were incubated at $20^{\circ}C$/TEX> for 45 min and subsequently incubated at $20^{\circ}C$/TEX> leaf color of wild-type plant became gradually white and all plantlets were finally died. Under the conditions in which all the wild-type plants died, more than 80% of the transformants remained green and survived. It was also found that the levels of Oshsp26 protein accumulated in transgenic plants were correlated with the degree of thermotolerance. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery, as a results, increases thermotolerance of whole plant during heat stress.

• Journal of Plant Biotechnology
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• v.37 no.1
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• pp.102-109
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• 2010

Fructan has been found to accumulate in various tissues during periods when light levels increased carbon fixation where low temperatures reduced growth rates while photosynthesis continued. In this study, we have cloned 1-sucrose:sucrose fructosyl transferase(1-sst) and 1-fructan: fructan fructosyl transferase (1-fft, a key enzyme for the synthesis of fuctan) from Jerusalem Artichoke (Helianthus tuberosus L.). The recombinant vector with 1-sst and 1-fft has been constructed under the control of 35S promoter of KJGV-B2 vector and transgenic plants obtained by Agrobacterium tumefaciens LBA4404. PCR analysis carried out on the putative transgenic plants for amplification of the coding region of specific gene (1-sst, 1-fft), and HPT genes. Transgenic lines carrying of 1-sst and 1-fft were confirmed for integration into the rice genome using Southern blot hybridization and RT-PCR. The transgenic plants in $T_2$ generation were selected and expression pattern analysis revealed that 1-sst and 1-fft were stable. This analysis confirmed the presence of low-molecular-weight fructan in the seedling of the transgenic rices. Therefore, cold tolerance and carbohydrate metabolism will be possible to develop resistant plants using the transgenic rice.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.247-255
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• 1992

A laboratory bioassay that incorporates Bacillus thuringiensis (Bt) purified crystal protein toxins into an artificial diet has identified three toxins, CryIA(b), CryIA(c), and CryIIA, to by effective against the yellow stemborer, Scirpophaga incertulas(Walker). Research is aimed at engineering rice that incorporates genes of one of or more of these toxins so as to mimic the insecticidal action of the insect to Bt. The paper discusses potential strategies for slowing the rate of adaptation that include the use of multiple Bt toxins, promoters that express the toxins only in specific plant tissues at specific times, and mixing transgenic and non-transgenic plants.

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.156-156
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• 2023

Salinity is a major abiotic stress that limits rice productivity in many regions of the world. In order to develop salt stress tolerant rice plants, genetic engineering is a promising approach. We characterized the molecular function of rice C3H2C3 as a really interesting new gene (RING). Oryza sativa RING finger protein H2-3 (OsRFPH2-3) was highly expressed in 100 mM NaCl. To identify the localization of OsRFPH2-3, we fused vectors that include C-terminal GFP protein (35S;;OsRFPH2-3-GFP). OsRFPH2-3 was expressed in the nucleus in rice protoplasts. An in vitro ubiquitin assay demonstrated that OsRFPH2-3 possessed E3-ubiquitin ligase activity. However, the mutated OsRFPH2-3 were not possessed any E3-ubiquitin ligase activity. Under salinity conditions, OsRFPH2-3-overexpressing plants exhibited higher chlorophyll, proline, SOD, POD, CAT, and soluble sugar contents and lower H₂O₂ accumulation than wild-type plants, supporting transgenic plants with enhanced salinity tolerance phenotypes. OsRFPH2-3-overexpressing plants exhibited low Na+ accumulation and Na+/K+ ratios in their roots. Theses results suggest that overexpression of OsRFPH2-3 can make plant insensitivity about salinity conditions.

• BMB Reports
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• v.42 no.1
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• pp.16-21
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• 2009

Three novel Class A genes that encode heat shock transcription factor (HSF) were cloned from Oryza Sativa L using a yeast hybrid method. The OsHSF7 gene was found to be rapidly expressed in high levels in response to temperature, which indicates that it may be involved in heat stress reception and response. Over-expression of OsHSF7 in transgenic Arabidopsis could not induced over the expression of most target heat stress-inducible genes of HSFs; however, the transcription of some HSF target genes was more abundant in transgenic plants following two hours of heat stress treatment. In addition, those transgenic plants also had a higher basal thermotolerance, but not acquired thermotolerance. Collectively, the results of this study indicate that OsHSF7 might play an important role in the response to high temperature. Specifically, these findings indicate that OsHSF7 may be useful in the production of transgenic monocots that can over-express protective genes such as HSPs in response to heat stress, which will enable such plants to tolerate high temperatures.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.283-288
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• 1998

The bialaphos is a potent inhibitor of glutamine synthease in higher plants and is used as a non-selective herbicide. We have used the bialaphos resistant gene(Bar) encoding for an acetyltransferase isolated from Streptomyces hygroscopicus SF1293. Callus derived from mature seeds of rice(Oryza sativa L. cv. Dong Jin) were co-cultivated with Agrobacterium tumefaciens EHA101 carring a plasmid pGPTV-HB containing genes for hygromycin resistance (HygR) and Bar. Transgenic plants showing in vitro resistance to 50 mg/L hygromycin and 10 mg/L bialaphos were obtained by using a two-step selection/regeneration procedure. Transformation efficiency of rice was about 30% which was as high as reported in other dicotyledons. Progenies ($\textrm{T}_{1}$ generation) derived from primary transformant of 17 lines were segregated with a 3 resistant : 1 sensitive ratio in medium containing hygromycin and bialaphos. Stable integration of Bar gene into chromosomal DNA was proven by Southern blot analysis of genomic DNA isolated from $\textrm{T}_{2}$ progenies. Transgenic plants ($\textrm{T}_{3}$) grown in the field were resistant to bialaphos (Basta) at a dosage lethal to wild type plants.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.225-232
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• 2010

The effect of Protox expression site on herbicidal resistance was investigated in wild-type and transgenic rice plants imposed by peroxidizing herbicide oxyfluorfen. The transgenic rice systems involved the plastidal expression of Arabidopsis protoporphyrinogen oxidase (Protox; AP line) and the dual expression of Myxococcus xanthus Protox in chloroplasts and mitochondria (TTS line). The oxyfluorfen-treated TTS4 line showed the lower levels of cellular leakage and malonyldialdehyde and the sustained capacity of 5-aminolevulinic acid synthesis, compared to the oxyfluorfen-treated AP and wild-type lines. During oxyfluorfen action, the TTS4 line had greater herbicide resistance than the AP1 line, indicating that the dual expression of M. xanthus Protox in chloroplasts and mitochondria prevented the accumulation of photodynamic protoporphyrin IX more effectively than the expression of Arabidopsis Protox only in chloroplasts. These results suggest that the ectopic expression of Protox in mitochondria greatly contributes to the herbicidal resistance in rice plants.