• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.164-164
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• 2017

High throughput transcriptome investigations of immunity in plants highlight the complexity of gene networks leading to incompatible interaction. To identify genes crucial to resistance against Xanthomonas oryzae pv oryzae, functional genetic analysis of selected differentially expressed genes from our microarray data set was carried out. A total of 13 overexpression vector constructs were made using 35S CaMV promoter which drive constitutive expression in rice. Most of the genes are developmentally expressed especially during maximum tillering stage and are commonly highly expressed in the leaves. When screened against Xoo strain K2, the transgenic plants displayed shorter lesion length compared with wild type Dongjin which indicates partial resistance. The levels of ROS continuously magnified after inoculation which indicates robust cellular sensing necessary to initiate cell death. Elevated transcripts levels of several defense-related genes at the downstream of defense signal network also corroborate the phenotype reaction of the transgenic plants. Moreover, expression assays revealed regulation of these genes by cross-communicating signal-transductions pathways mediated by salicylic and jasmonic acid. These collective findings revealed the key immune signaling conduits critical to mount full defense against Xoo.

• 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 the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.730-735
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• 2013

This study compared the nutritional components (proximate components, fatty acids, amino acids, minerals and vitamins) between genetically modified (GM) drought-tolerant rice and a parental rice cultivar (Ilmibyeo) as a non-GM control. Both GM and non-GM rices were grown and harvested in two different locations, Gunwi and Suweon in Korea. Proximate components (moisture, starch, protein, lipid, and ash contents) were similar between the drought-tolerant GM rice and the conventional non-GM rice. There were no significant differences between the GM and non-GM rice in most of their nutrient compositions, despite minor locational differences of some amino acids and minerals. These results indicate that transgenic rice with a genetically improved resistance to drought is equivalent to the parental rice cultivar without major changes in its chemical contents.

• KSBB Journal
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• v.31 no.4
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• pp.284-290
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• 2016

In this research, recombinant human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) was produced by transgenic rice cells. RAmy3D promoter was used for overcome the limitation of low expression level in transgenic plant cells, and the secretion of target protein was accomplished by signal peptide. However, the RAmy3D promoter system which can be induced only by sugar starvation causes the decrease of cell viability. As a result, cell death promotes the release of protease which degrades the target proteins. The protein stability and productivity can be significantly influenced by proteolysis activity. Therefore, development of new strategies are necessary for the in situ recovery of target proteins from cell culture media. In this study, in situ recovery was performed by various strategies. Direct addition of Protein A resin with nylon bag leads to cell death by increased shear stress and decrease in production of hCTLA4Ig by protease. Medium exchange through modified flask could recover hCTLA4Ig with high cell viability and low protease activity, on the other hand, the productivity was lower than that of control. When in situ recovery was conducted at day 7 after induction in air-lift bioreactor, 1.94-fold of hCTLA4Ig could be recovered compared to control culture without in situ recovery. Consequently, in situ recovery of hCTLA4Ig from transgenic rice cell culture could enhance productivity significantly and prevent degradation of target proteins effectively.

• KSBB Journal
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• v.26 no.5
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• pp.386-392
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• 2011

Human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig), an immunosuppressive agent, was expressed in transgenic rice cells using RAmy3D promoter and RAmy1A signal peptide for the inducible production and secretion into culture media by sugar depletion. In this study, sodium butyrate was used as a small molecular enhancer (SME) to enhance the production of hCTLA4Ig in transgenic rice cell suspension cultures. When 1 mM sodium butyrate was added in sugar-free media, relative viability was not reduced, while the productivity was improved 1.3-fold. In addition, by supplementing 87 mM sodium pyruvate as an alternative energy source during the production phase, death rate of the cells was decreased. When sodium pyruvate was not added, most cells became dead at day 6. However, by adding sodium pyruvate, 18% of viability can be maintained until day 10 and the production of hCTLA4Ig was enhanced 1.4-fold. When the combination of sodium pyruvate and sodium butyrate at optimum concentrations was added, the highest viability and hCTLA4Ig production could be obtained. The highest level of hCTLA4Ig reached up to 35 mg/L at day 10.

• Korean Journal of Plant Resources
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• v.20 no.5
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• pp.437-441
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• 2007

The argE gene of E.coli was introduced into #Ilmibyeo# cultivar of rice by Agrobacterium tumefaciens and a large number of transgenic plants were produced. Embryogenic calli were co-cultivated with A. tumefaciens strain AGL1 carrying the plasmid pCAMBIA1300 containing hygromycin resistance(HygR). Transgenic plants showing in vitro resistance to 50mg/L hygromycin were obtained using a selection procedure. Stable integration of argE and HPT genes into chromosomal DNA was proven by southern blot analysis and PCR analysis of genomic isolated from $T_0$ progenies. The fragments of 650 bp(HPT) were detected in transgenic rice lines. The 230 bp(argE) fragments were showed in agarose gel, and detected fragments were matched with size of argE specific primer. The microscopic feature of leaf on scanning electron microscope(SEM) revealed differences between clear and chalky in shape and arrangement of stoma but did not discriminate.

• KSBB Journal
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• v.20 no.4
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• pp.278-284
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• 2005

An immunosuppressive agent, human cytotoxic T lymphocyte antigen 4 (hCTLA4), is used for the prevention of graft rejection and treatment of autoimmune diseases. hCTLA4-Ig, a CTLA4-immunoglobulin fusion protein, was produced and secreted from transgenic rice cell suspension cultures using rice a-amylase (RAmy3D) expression system. In this system, hCTLA4-Ig expression was regulated metabolically by sugar starvation. For the purpose of improving hCTLA4-Ig production, the effects of osmotic pressure was investigated in suspension cultures of transgenic rice cells. The highest production level was achieved at 40 mM sorbitol $(140\;mOsm{\cdot}kg^{-1}\;H_2O)$. Using the medium with 8 mM glucose, the level of hCTLA4-Ig in the medium reached 45.3 mg/L. By adjusting the osmotic pressure of induction medium, it was found that the hCTLA4-Ig production could be increased up to 2.1-fold compared with that in batch culture.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.159-159
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• 2017

Drought, a common environmental constraint, induces a range of physiological, biochemical and molecular changes in plants, and can cause severe reductions in crop yield. Consequently, understanding the molecular mechanisms of drought tolerance is an important step towards crop biotechnology. Here, we report that the rice (Oryza sativa) homeodomain-leucine zipper class IV transcription factor gene, ${\underline{R}ice}$ ${\underline{o}utermost}$ ${\underline{c}ell-specific}$ gene 10 (Roc10), enhances drought tolerance and grain yield by increasing lignin accumulation in ground tissues. Overexpression of Roc10 in rice significantly increased drought tolerance at the vegetative stages of growth and promoted both more effective photosynthesis and a reduction in water loss rate, compared with non-transgenic controls or RNAi transgenic plants. Importantly, Roc10 overexpressing plants had a higher drought tolerance at the reproductive stage of growth and a higher grain yield compared with the controls under field-drought conditions. Roc10 is mainly expressed in outer cell layers including the epidermis and the vasculature of the shoots, which coincides with areas of cell wall lignification. Roc10 overexpression elevated the expression levels of lignin biosynthetic genes in shoots, with a concomitant increase in the accumulation of lignin, while the overexpression and RNAi lines showed opposite patterns of lignin accumulation. We identified downstream target genes of Roc10 by performing RNA-seq and chromatin immunoprecipitation (ChIP)-seq analyses of shoot tissues. Roc10 was found to directly bind to the promoter of PEROXIDASEN/PEROXIDASE38, a key gene in lignin biosynthesis. Together, our findings suggest that Roc10 confers drought stress tolerance by promoting lignin biosynthesis in ground tissues.

• KSBB Journal
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• v.24 no.3
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• pp.246-252
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• 2009

Rice cells were transformed to express human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig) using RAmy3D promoter. hCTLA4Ig was produced and secreted into culture media inducibly when sugar was depleted. The obstacles of this system are the cell death and release of proteases by sugar starvation. These problems resulted in the losses of stability and productivity of hCTLA4Ig. Therefore, the effects of proline as an inhibitor of cell death were investigated. When 4 mM proline was added in sugar-free media, the cell death and release of proteases were reduced. As a consequence, the production of hCTLA4Ig was enhanced. In addition, the effects of protein stabilizers such as gelling agents were studied. It was found that the application of 0.01 g/L gelatin led to an increase in hCTLA4Ig production. This increase might be originated from the stabilization of hCTLA4Ig. In conclusion, the production of hCTLA4Ig could be enhanced by the additions of proline and gelatin in transgenic rice cell cultures.

• Journal of Life Science
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• v.22 no.9
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• pp.1173-1179
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• 2012

The importance of genetic stability and bio-safety in the environment has recently been recognized for many (genetically modified) GM plants. This study evaluated the GM safety of transgenic rice and its environmental variance. Data on agronomic characters and principal component were collected for vitamin A-enriched GM rice and four check cultivars in a large GM field trial during 2009-2011. The cultivation environment was a large GM field and a greenhouse. In this experiment, there was no significant difference between the agronomic characters of the GM rice and those of a donor plant, 'Nagdong'. In terms of grain characteristics, the appearance and physicochemical characteristics of the GM rice and those of the donor plant were similar. However, the grain of the GM rice developed a white core and a white belly when planted in the greenhouse. The type and distribution of dominant weed species were not different in the GM rice and the 'Nagdong'. In addition, gene flow was not detected in the dominant weed species based on PCR analysis.