• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04a
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, $50-80\%$ of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, Improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.41-47
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• 2002

Adverse environmental conditions such as drought, high salt and cold/freezing are major factors that reduces crop productivity worldwide. According to a survey, 50-80% of the maximum potential yield is lost by these 'environmental or abiotic stresses', which is approximately ten times higher than the loss by biotic stresses. Thus, improving stress-tolerance of crop plants is an important way to improve agricultural productivity. In order to develop such stress-tolerant crop plants, we set out to identify key stress signaling components that can be used to develop commercially viable crop varieties with enhanced stress tolerance. Our primary focus so far has been on the identification of transcription factors that regulate stress responsive gene expression, especially those involved in ABA-mediated stress response. Be sessile, plants have the unique capability to adapt themselves to the abiotic stresses. This adaptive capability is largely dependent on the plant hormone abscisic acid (ABA), whose level increases under various stress conditions, triggering adaptive response. Central to the response is ABA-regulated gene expression, which ultimately leads to physiological changes at the whole plant level. Thus, once identified, it would be possible to enhance stress tolerance of crop plants by manipulating the expression of the factors that mediate ABA-dependent stress response. Here, we present our work on the isolation and functional characterization of the transcription factors.

• Korean Journal of Environmental Agriculture
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• v.29 no.2
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• pp.159-164
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• 2010

Imidacloprid is a systemic insecticide which has been used widely in various crops to control insects. In the present study, we demonstrated that pre-treatment of imidacloprid significantly induced tolerance to drought in plant. Relative water content, chlorophyll levels, and recovery rate upon rehydration after drought stress in tobacco plants pre-treated with imidacloprid were higher levels than the control plants. Induced drought tolerance by imidacloprid treatments in red pepper was also demonstrated by measurement of recovery rate and fresh weight upon drought stress. Taken together, our results suggest that imidacloprid, in addition to exerting direct insecticidal activity, may also protect plants by induced tolerance to drought in plant.

• Journal of Plant Biotechnology
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• v.6 no.4
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• pp.205-212
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• 2004

The objectives were to compare the salt tolerance levels in the parental rice cultivar, Dongjinbyeo, and induced mutagenesis derived its lines for plant height, MDA, ATPase, POD, and 2-dimensional protein electrophoresis pattern in NaCl-containing hydroponic nutrient solutions. Rice plants isolated from a population of rice (Oryza sativa L. cv. Dongjinbyeo) mutation lines, which were generated in combination with in vitro selection and gamma-ray, exhibited salt tolerance. Line No. 18 had the longest plant, whereas NaCl-sensitive line (No. 25) had the shortest plant. The parent, and the sensitive line showed severe damage from salt stress. Tolerant lines (No. 18, 50) had a lower malonaldehyde (MDA) content than the sensitive one (Dongjinbyeo, No. 25) during salt stress. Several proteins showed significant quantitative variation through 2DE; phosphoribulokinase, peroxidase, oxygen evolving enhancer 1 and the $H^+-ATPase$, which are known to be involved in salt tolerance. The effect of salt on peroxidase and $H^+-ATPase$ activity in the seedlings of two groups with contrasting genotypes of rice was studied. A greater activity was recorded in the tolerant lines as compared to the sensitive ones (P<0.05, Duncan's test). The results indicate that salt tolerant lines expressed more salt stress-inducible proteins associated with salt tolerance than the sensitive lines during salt stress.

• Journal of Plant Biotechnology
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• v.32 no.3
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• pp.151-159
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• 2005

Injury caused by reactive oxygen species (ROS), known as oxidative stress, is one of the major damaging factors in plants exposed to environmental stress. Chloroplasts are specially sensitive to damage by ROS because electrons that escape from the photosynthetic electron transfer system are able to react with relatively high concentration of $O_2$ in chloroplasts. To cope with oxidative stress, plants have evolved an efficient ROS-scavenging enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX), and low molecular weight antioxidants including ascorbate, glutathione and phenolic compounds. To maintain the productivity of plants under the stress condition, it is possible to fortify the antioxidative mechanisms in the chloroplasts by manipulating the antioxidation genes. A powerful gene expression system with an appropriate promoter is key requisite for excellent stress-tolerant plants. We developed a strong oxidative stress-inducible peroxidase (SWPA2) promoter from cultured cells of sweetpotato (Ipomoea batatas) as an industrial platform technology to develop transgenic plants with enhanced tolerance to environmental stress. Recently, in order to develop transgenic sweetpotato (tv. Yulmi) and potato (Solanum tuberosum L. cv. Atlantic and Superior) plants with enhanced tolerance to multiple stress, the genes of both CuZnSOD and APX were expressed in chloroplasts under the control of an SWPA2 promoter (referred to SSA plants). As expected, SSA sweetpotato and potato plants showed enhanced tolerance to methyl viologen-mediated oxidative stress. In addition, SSA plants showed enhanced tolerance to multiple stresses such as temperature stress, drought and sulphur dioxide. Our results strongly suggested that the rational manipulation of antioxidative mechanism in chloroplasts will be applicable to the development of all plant species with enhanced tolerance to multiple environmental stresses to contribute in solving the global food and environmental problems in the 21st century.

• Molecules and Cells
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• v.39 no.6
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• pp.447-459
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• 2016

Many studies have been conducted to understand plant stress responses to salinity because irrigation-dependent salt accumulation compromises crop productivity and also to understand the mechanism through which some plants thrive under saline conditions. As mechanistic understanding has increased during the last decades, discovery-oriented approaches have begun to identify genetic determinants of salt tolerance. In addition to osmolytes, osmoprotectants, radical detoxification, ion transport systems, and changes in hormone levels and hormone-guided communications, the Salt Overly Sensitive (SOS) pathway has emerged to be a major defense mechanism. However, the mechanism by which the components of the SOS pathway are integrated to ultimately orchestrate plant-wide tolerance to salinity stress remains unclear. A higher-level control mechanism has recently emerged as a result of recognizing the involvement of GIGANTEA (GI), a protein involved in maintaining the plant circadian clock and control switch in flowering. The loss of GI function confers high tolerance to salt stress via its interaction with the components of the SOS pathway. The mechanism underlying this observation indicates the association between GI and the SOS pathway and thus, given the key influence of the circadian clock and the pathway on photoperiodic flowering, the association between GI and SOS can regulate growth and stress tolerance. In this review, we will analyze the components of the SOS pathways, with emphasis on the integration of components recognized as hallmarks of a halophytic lifestyle.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.776-782
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• 2016

Salinity has been a threat to agriculture in some parts of the world; and recently, the threat has grown. Plant growth-promoting rhizobacteria (PGPR) may benefit plant growth, either by improving plant nutrition or producing plant growth hormones. The effects of rhizobacterial strains to attenuate the salinity stress on the germination of Chinese cabbage seeds were tested using four different concentrations of NaCl (50, 100, 150, and 200 mM). Also, PGPR strains were tested to enhance the early germination of Chinese cabbage seeds under normal conditions. Azotobacter chroococcum performed best with enhancing the radicle length of 4.0, 1.2, and 1.0 times at treatments of 50, 100, and 150 mM of NaCl, respectively. Additionally, significant differences were found in plumule length, A. chroococcum and Lactobacillus sp. showed remarkable activation either in normal or under stress conditions. Co-inoculation by three rhizobacterial strains (LAPmix) indicated synergistic effect to enhance the early germination of the seeds. The results of this study are promising for application of rhizobacterial strains that possess plant growth promoting traits to enhance the plant tolerance against salinity.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.195-195
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• 2022

Abiotic stress is a major problem in global agriculture as it negatively affects crop growth, yield, and quality. Wheat (Triticum aestivum) is the world's second-highest-producing food resource, so the importance of mitigating damage caused by abiotic stress has been emerging. In this study, we performed GWAS to search for SNPs associated with salt tolerance and drought tolerance. NaCl (200 mM) treatment was performed at the seedling stage using 613 wheat varieties in Korean wheat core collection. Root length, root surface area, root average diameter, and root volume were measured. Drought stress was applied at the seedling stage, and the above phenotypes were measured. GW AS was performed for each phenotype data using the MLM, MLMM, and FarmCPU models. The best salt-tolerant wheat varieties were 'MK2402', 'Gyeongnam Geochang-1985-3698', and 'Milyang 13', showing superior root growth. The significant SNP AX-94704125 (BA00756838) were identified in all models. The genes closely located to the significant SNP were searched within ± 250 kb of the corresponding SNP. A total of 11 genes were identified within the region. NB-ARC involved in the defense response, FKSI involved in cell wall biosynthesis, and putative BP Ml involved in abiotic stress responses were discovered in the 11 genes. The best drought-tolerant wheat varieties were 'PI 534284', 'Moro of Sind', and 'CM92354-33M-0Y-0M-6Y-0B-0BGD', showing superior root growth. This study discovered SNPs associated with salt tolerance in Korean wheat core collection through GWAS. GWAS of drought tolerance is now proceeding, and the GWAS results will be represented on a poster. The SNPs identified by GWAS can be useful for studying molecular mechanisms of salt tolerance and drought tolerance in wheat.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.168-168
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• 2005