• The Plant Pathology Journal
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• v.29 no.4
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• pp.471-476
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• 2013

Plants are frequently exposed to numerous environmental stresses such as dehydration and high salinity, and have developed elaborate mechanisms to counteract the deleterious effects of stress. The phytohormone abscisic acid (ABA) plays a critical role as an integrator of plant responses to water-limited condition to activate ABA signal transduction pathway. Although perception of ABA has been suggested to be important, the function of each ABA receptor remains elusive in dehydration condition. Here, we show that ABA receptor, pyrabactin resistance-like protein 8 (PYL8), functions in dehydration conditions. Transgenic plants overexpressing PYL8 exhibited hypersensitive phenotype to ABA in seed germination, seedling growth and establishment. We found that hypersensitivity to ABA of transgenic plants results in high degrees of stomatal closure in response to ABA leading to low transpiration rates and ultimately more vulnerable to drought than the wild-type plants. In addition, high expression of ABA maker genes also contributes to altered drought tolerance phenotype. Overall, this work emphasizes the importance of ABA signaling by ABA receptor in stomata during defense response to drought stress.

• Journal of Plant Biotechnology
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• v.4 no.2
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• pp.53-58
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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.n factors.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.100-106
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• 2006

A hypertonic solution of sorbitol was used to precondition Douglas-fir and Western hemlock plug seedlings to improve desiccation resistance. Seedlings were preconditioned by soaking their root balls in water, -0.75 or -1.50 MPa sorbitol solution for 22 hr, and then exposed to desiccation conditions for 8 days. During the desiccation period, a transpirational water loss was significantly reduced by the sorbitol preconditioning, with its effect positively depending on concentration. This preconditioning-induced reduction in water loss was mainly caused by the decline in needle stomatal conductance. Sorbitol-induced stomatal control was more closely associated with reduction in plant water potential, rather than increase in abscisic acid concentrations. After rehydration of stressed-plants, most of the preconditioned seedlings with sorbitol were survived, while only 35% of Douglas-fir and 28% of Western hemlock seedlings treated with water were alive. The post-growth was significantly greater in the preconditioned seedlings than only water-treated seedlings. These results suggested that the earlier stomatal control with sorbitol-facilitated preconditioning could play a role in improving desiccation resistance of evergreen woody plants at transplanting in the field where water supply is limited or dry conditions are prevailing.

• Proceedings of the Korean Society of Crop Science Conference
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• 1993.10a
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• pp.44-45
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• 1993

• Journal of Ginseng Research
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• v.40 no.4
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• pp.409-414
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• 2016

Background: The low survival rate of in vitro regenerated Panax ginseng plantlets after transfer to soil is the main obstacle for their successful micropropagation and molecular breeding. In most cases, young plantlets converted from somatic embryos are transferred to soil. Methods: In vitro thickened taproots, which were produced after prolonged culture of ginseng plantlets, were transferred to soil. Results: Taproot thickening of plantlets occurred near hypocotyl and primary roots. Elevated concentration of sucrose in the medium stimulated the root thickening of plantlets. Senescence of shoots occurred following the prolonged culture of plantlets. Once the leaves of plantlets senesced, the buds on taproots developed a dormant tendency. Gibberellic acid treatment was required for dormancy breaking of the buds. Analysis of endogenous abscisic acid revealed that the content of abscisic acid in taproots with senescent shoots was comparatively higher than that of taproots with green shoots. Thickened taproots were transferred to soil, followed by exposure to gibberellic acid or a cold temperature of $2^{\circ}C$ for 4 mo. Cold treatment of roots at $2^{\circ}C$ for 4 mo resulted in bud sprouting in 84% of roots. Spraying of 100 mg/L gibberellic acid also induced the bud sprouting in 81% roots. Conclusion: Soil transfer of dormant taproots of P. ginseng has advantages since they do not require an acclimatization procedure, humidity control of plants, and photoautotrophic growth, and a high soil survival rate was attained.

• Natural Product Sciences
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• v.23 no.4
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• pp.253-257
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• 2017

The phytochemical study for the extract of Nelumbo nucifera (Nymphaceae) seeds has led to the isolation of ten compounds including five simple phenolic compounds, two indole derivatives, a flavonoid glycoside, two abscisic acid derivatives. The interpretation of 1D and 2D NMR and ESI-Q-TOF-MS spectroscopic data revealed the chemical structures of isolates to be p-hydroxybenzoic acid (1), protocatechuic acid (2), (E)-p-coumaric acid (3), (E)-ferulic acid (4), (E)-sinapate-4-O-${\beta}$-$\text\tiny{D}$-glucopyranoside (5), tryptophan (6), 3-indoleacetic acid (7), isoschaftoside (8), dihydrophaseic acid (9), dihydrophaseic acid 3'-O-${\beta}$-$\text\tiny{D}$-glucopyranoside (10). To the best of our knowledge, 1 - 5 and 7 were identified for the first time from N. nucifera seeds, and the presence of dihydrophaseic acid (9) and its glucoside (10) were demonstrated secondly in this plant.

• Horticultural Science & Technology
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• v.29 no.1
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• pp.1-9
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• 2011

This study was performed to investigate the role of plant growth substances on the bulbing of cold type of garlic (Allium sativum L. cv. Uiseongmaneul) during long and short day conditions. The change in endogenous plant hormones such as abscisic acid (ABA), jasmonic acid (JA) and sugar contents in leaf blade and sheath was examined during the growth stage from bulb differentiation (starting at April 16) to bulbing (April 24 to May 18) in cold type of garlic. In the long day condition, ABA contents were higher than short day condition and ABA contents of leaf sheath were higher than leaf blade. ABA contents of growth stage in garlic were not changed during growth stage from April 16 to May 2, however it rapidly increased during bulbing (May 2 to May 18). On the other hand, endogenous JA contents in short day condition did not change in long day condition, it increased from April 16 to May 2. JA contents in the leaf sheath (33.85-62.04 $ng{\cdot}g^{-1}$ DW) were higher than leaf blade (15.39-30.04 $ng{\cdot}g^{-1}$ DW). These results showed that garlic bulb differentiation and bulbing was induced by JA in leaf sheath. In long day condition, total sugar contents in the leaf blade were increased from bulb differentiation (April 16) to bulbing (May 4) and it was decreased during bulbing (May 4 to May 18) while the total sugar content in leaf sheath were gradually increased from bulb differentiation (April 16) to bulbing (May 18). In conclusion, our results showed that there is a significant correlation between the bulb development of garlic and hormonal content in the leaf sheath.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.1-10
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• 2020

Since salicylic acid (SA) was discovered as an elicitor of tobacco plants inducing the resistance against Tobacco mosaic virus (TMV) in 1979, increasing reports suggest that SA indeed is a key plant hormone regulating plant immunity. In addition, recent studies indicate that SA can regulate many different responses, such as tolerance to abiotic stress, plant growth and development, and soil microbiome. In this review, we focused on the recent findings on SA's effects on resistance to biotic stresses in different plant-pathogen systems, tolerance to different abiotic stresses in different plants, plant growth and development, and soil microbiome. This allows us to discuss about the safe and practical use of SA as a plant defense activator and growth regulator. Crosstalk of SA with different plant hormones, such as abscisic acid, ethylene, jasmonic acid, and auxin in different stress and developmental conditions were also discussed.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.406-413
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• 2009

The enzyme invertase contributes to sugar unloading, pathogen defense, differentiation and development in plants. We cloned the complete cDNA of a soluble acid invertase from pea seedlings (Pisum sativum) via RT-PCR and the rapid amplification of the cDNA end (RACE) technique. The full-length cDNA of the soluble pea invertase comprised 2237 bp and contained a complete open reading frame encoding 647 amino acids. The deduced amino acid sequence showed high homology to soluble acid invertases from various plants. Northern blot analysis demonstrated the soluble acid invertase gene of P. sativum was strongly expressed in sink organs such as shoot tips and root tips, and induced by abscisic acid, gibberellic acid and jasmonic acid in shoots. Especially, gibberellic acid enhanced the gene expression of the soluble acid invertase in a time-dependent manner. This study presents that the gene expression patterns of a soluble acid invertase from pea are strongly consistent with the suggestion that individual invertase gene product has different functions in the growing plant.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.557-564
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• 2013

We isolated and identified antioxidants from acidic and neutral ethyl acetate fractions of the peel of pear (Pyrus pyrifolia N. cv. Chuhwangbae). We isolated 4 compounds from the methanol extract, by using 3 different types of column chromatography (Sephadex LH-20, silica gel, and octadecylsilane) and preparative HPLC. We identified the isolated compounds as (S)-(+)-2-cis-abscisic acid O-${\beta}$-D-glucopyranosyl ester (compound 1), 1-[4-O-${\beta}$-D-glucopyranosyl]phenyl ethanone (picroside, compound 2), ${\beta}$-sitosterol (compound 3), and ${\beta}$-sitosteryl 3-O-${\beta}$-D-glucopyranoside (compound 4) by nuclear magnetic resonance analysis. We are the first to report the identification of compounds 1, 2, and 4 from pear.