• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.205-214
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• 2016

A drought-tolerant transgenic rice (Agb0103) was developed using a pepper methionine sulfoxide reductase (CaMsrB2) under the control of rice Rab21 promoter with a selection marker, the phosphinothricin acetyltransferase (PAT) gene. Commercialization of genetically modified (GM) crops will require the evaluation of risks associated with the release of GM crops. With the potential problems associated to GM crops safety testing, the investigation of their effects on non-target organisms is necessary for environmental risk research. This study was carried out to assess acute toxicity of a GM crop using the water flea (Daphnia magna) for non-target organism risk evaluation. The effect of acute toxicity on Daphnia magna of Agb0103 rice and a non-GM rice, Ilmibyeo, were investigated at different concentrations (0, 625, 1,250, 2,500, 5,000, and 10,000 mg/L). The Agb0103 rice used for the test was confirmed to express the CaMsrB2/PAT gene by the PCR and ELISA. Daphnia magna feeding tests showed no significant differences in cumulative immobility or abnormal response with either Agb0103 rice or non-GM rice. The 48hr-EC50 values showed no difference between Agb0103 rice (2243 mg/L) and non-GM rice (2694 mg/L). These results suggest that there is no significant difference in toxicity to Daphnia magna between Agb0103 rice and its non-GM counterpart.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.1
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• pp.42-49
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• 2023

The plant-specific NAC transcription factors control various biological processes, including plant development and stress responses. We have isolated an ANAC032 gene, one of the NAC transcription factor family, which was highly activated by multi-abiotic stresses, including high salt and drought in Arabidopsis. Here, we generated transgenic plants constitutively expressing ANAC032 and its knockout to identify the functional roles of ANAC032 in Arabidopsis under abiotic stress responses. The ANAC032-overexpressing plants showed enhanced tolerance to salinity and drought stresses. The anac032 knockout mutants were observed no significant changes under the high salt and drought conditions. We also monitored the expression of high salt and drought stress-responsive genes in the ANAC032 transgenic plants and anac032 mutant. The ANAC032 overexpression upregulated the expression of stress-responsive genes, RD29A and ERD10, under the stresses. Thus, our data identify that transcription factor ANAC032 plays as an enhancer for salinity and drought tolerance through the upregulation of stress-responsive genes and provides useful genetic traits for generating multi-abiotic stress-tolerant forage crops.

• Current Research on Agriculture and Life Sciences
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• v.21
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• pp.1-9
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• 2003

Plants are often subjected to periods of soil and atmospheric water deficit during their life cycle. To find critical levels for identification of tolerant rice variety to salt- and drought-stresses, we investigated the water deficiency in the leaf of a Dongjinbyeo (DJ) cultivar, identified as intolerant variety, subjected to NaCl- and Polyethylene glycol 6000 (PEG)- treatments. The relative water content and water potential in leaf of DJ plant sharply declined along the high concentration and time after treatment in NaCl- and PEG-treated rice plants. To elucidate the method of simple screening of tolerant variety to salt- and drought-stresses, we examined the relationship between relative water content and water potential of leaves in NaCl- and PEG-treated rice plants. The relationship between relative water content and water potential in leaf of DJ plant showed the highest correlation in 80 mM NaCl-treatment, and showed high correlation only 8% PEG treatment. These results indicate that the critical level of salt stress for screening of tolerant rice was 80 mM NaCl at 48 h after NaCl treatment, and the critical concentration of drought stress for screening of tolerant rice was 8% PEG at 96 h after PEG treatment.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.302-310
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• 2016

A study aimed at identifying putative drought responsive genes that confer tolerance to water stress deficit in tea plants was conducted in a 'rain-out shelter' using potted plants. Eighteen months old drought tolerant and susceptible tea cultivars were each separately exposed to water stress or control conditions of 18 or 34% soil moisture content, respectively, for three months. After the treatment period, leaves were harvested from each treatment for isolation of RNA and cDNA synthesis. The cDNA libraries were sequenced on Roche 454 high-throughput pyrosequencing platform to produce 232,853 reads. After quality control, the reads were assembled into 460 long transcripts (contigs). The annotated contigs showed similarity with proteins in the Arabidopsis thaliana proteome. Heat shock proteins (HSP70), superoxide dismutase (SOD), catalase (cat), peroxidase (PoX), calmodulinelike protein (Cam7) and galactinol synthase (Gols4) droughtrelated genes were shown to be regulated differently in tea plants exposed to water stress. HSP70 and SOD were highly expressed in the drought tolerant cultivar relative to the susceptible cultivar under drought conditions. The genes and pathways identified suggest efficient regulation leading to active adaptation as a basal defense response against water stress deficit by tea. The knowledge generated can be further utilized to better understand molecular mechanisms underlying stress tolerance in tea.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.341-341
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• 2017

Abiotic stress adversely affects crop growth worldwide. Drought of the major abiotic stresses have the most significant impact on all of the crop. The main objective of this study was to assess the effects of drought stress on photochemical performance and vitality of maize (Zea mays L.). The photochemical characteristics were analyzed in the context of period of drought stress during the maize growth. Drought experiment was carried out for four weeks, thereafter, the drought treated maize was re-watered. The polyphasic OJIP fluorescence transient was used to evaluate the behavior of photosystem II (PSII) and photosystem I (PSI) during the entire experiment period. In drought stress, the performance Index (PI) level was reached earlier when compared to the controls. For the screening of drought stress tolerance the drought factor index (DFI) of each variety was calculated as follow DFI= log(A) + 2log(B). All the fourteen cultivars show DFI ranged from -0.69 to 0.30, meaning less useful in selection of drought tolerant cultivars. PI and electron transport flux values of fourteen cultivars were to indicate reduction of photosynthetic performance during the early vegetative stage under drought stress. In conclusion, DFI and energy flux parameters can be used as photochemical and physiological index.

• BMB Reports
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• v.42 no.5
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• pp.271-276
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• 2009

Sweetpotato (Ipomoea batatas (L). Lam.) is relatively tolerant to unfavorable growth conditions such as drought, yet has not been exploited to provide a better understanding of the molecular basis of drought stress tolerance. We obtained 983 high-quality expressed sequence tags of 100 bp or longer (average length of 700 bp) from cDNA libraries of detached white fibrous root tissues by subjecting them to dehydration for 6 h. The 431 cDNAs were each assigned a function by alignment using the BLASTX algorithm. Among them, three genes associated with various abiotic stresses and nine genes not previously associated with drought stress were selected for expression pattern analysis through detailed reverse transcription-polymerase chain reaction. The direct and indirect relationships of the 12 genes with drought tolerance mechanisms were ascertained at different developmental stages and under various stress conditions.

• Journal of Korean Society of Forest Science
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• v.80 no.2
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• pp.210-219
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• 1991

This study is to diagnose the drought tolerance of twenty broad-leaved tree species by the pressure-volume(P-V) curves. As for the diagnosis of drought tolerance, the valuable water relations parameters obtained from P-V curves are the osmotic potential at full turgor, ${\Psi}_0{^{sat}}$, osmotic potential at incipient plasmolysis, ${\Psi}_0{^{tlp}}$, maximum bulk modulus of elasticity, $E_{max}$, and relative water content at incipient plasmolysis, $RWC^{tlp}$. Also, the figures related to the diagnosis of drought tolerance are the free water content (FWC) versus leaf water potential(${\Psi}_L$), volume-averaged turgor pressure ($P_{vat}$) versus leaf water potential (${\Psi}_L$), and H$\ddot{o}$fler diagram. In this study, the relatively high drought tolerant species are Fraxinus rhynchophylla, Quercus acutissima, Quercus serrata, Quercus aliena, and Populus alba${\times}$glandulosa ; the relatively low drought tolerant species are Fraxinus mandshurica, Betula platyphylla var. japonica, Populus euramericana, Kalopanax pictum, Carpinus loxiflora, Carpinus cordata, Prunus sargentii, Prunus leveilleana, and Cornus controversa ; medium species are Quercus mongolica, Acer mono, Acer triflorum, Acer pseudo-sieboldianum, Ulmus davidiana, and Zelkova serrata.

• Molecules and Cells
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• v.39 no.3
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• pp.250-257
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• 2016

Abiotic stresses such as drought and low temperature critically restrict plant growth, reproduction, and productivity. Higher plants have developed various defense strategies against these unfavorable conditions. CaPUB1 (Capsicum annuum Putative U-box protein 1) is a hot pepper U-box E3 Ub ligase. Transgenic Arabidopsis plants that constitutively expressed CaPUB1 exhibited drought-sensitive phenotypes, suggesting that it functions as a negative regulator of the drought stress response. In this study, CaPUB1 was over-expressed in rice (Oryza sativa L.), and the phenotypic properties of transgenic rice plants were examined in terms of their drought and cold stress tolerance. Ubi:CaPUB1 T3 transgenic rice plants displayed phenotypes hypersensitive to dehydration, suggesting that its role in the negative regulation of drought stress response is conserved in dicot Arabidopsis and monocot rice plants. In contrast, Ubi:CaPUB1 progeny exhibited phenotypes markedly tolerant to prolonged low temperature ($4^{\circ}C$) treatment, compared to those of wild-type plants, as determined by survival rates, electrolyte leakage, and total chlorophyll content. Cold stress-induced marker genes, including DREB1A, DREB1B, DREB1C, and Cytochrome P450, were more up-regulated by cold treatment in Ubi:CaPUB1 plants than in wild-type plants. These results suggest that CaPUB1 serves as both a negative regulator of the drought stress response and a positive regulator of the cold stress response in transgenic rice plants. This raises the possibility that CaPUB1 participates in the cross-talk between drought and low-temperature signaling pathways.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.1
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• pp.39-44
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• 2019

Drought is one of the key limiting factors that adversely affects the growth and productivity of crop plants. For the enhancement of drought tolerance in crop plants, the identification of basic mechanisms of a plant to drought stress is necessary. In this study, we compared physiological and biochemical responses of five local Arundenilla hirta ecotypes to drought stress. These ecotypes were previously collected from various parts of Korean peninsula, including Youngduk, Gunsan, Jangsoo, Jinju-1 and Yecheon. A. hirta plants were exposed to drought stress for 14 and 17 days respectively, followed by re-watering for 3 days. The results showed that the lipid peroxidation (MDA), hydrogen peroxide ($H_2O_2$), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, and proline level were significantly increased while the chlorophyll content was decreased by drought stress in A. hirta leaves. The highest proline content and DPPH scavenging activity were shown in Ecotype of Youngduk with least MDA and $H_2O_2$ levels while the highest MDA and $H_2O_2$ contents, and least proline and DPPH levels were shown in Gunsan, respectvely. These results indicate that the Youngduk is the most tolerant and Gunsan is the most sensitive ecotype among the five different collections. Together, these results provide a new insight of overall physiological responses of A. hirta to drought stress.

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.06a
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• pp.173-173
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• 2020