• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.245-245
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• 2022

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.04a
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• pp.24-24
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• 2022

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6852-6859
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• 2015

The purpose of this study was to determine the growth characteristics and distribution pattern of a brackish water clam Corbicula japonica in Seomjin River. Field samples were taken from 14 stations with salinity gradients during spring. Salinity at the bottom layer ranged from 1.0 psu to 32.9 psu, with low salinities in the upper area of the river. In particular, salinity at St.11 was decreased drastically to be ca. 15.0 psu, indicating an intermediate salinity zone. The distribution pattern of C. japonica was related to the salinity gradient, with the highest densities of $2,102ind.m^{-2}$ at Station 13, followed by $1,507ind.m^{-2}$ at Station 11. Here, we focused on the growth characteristics of collected C. japonica collected at two stations with different salinity values. The relationship between shell length and total weight was highly correlated ($R^2=0.91$, P<0.001) at Station 13 compared to that at Station 11 ($R^2=0.72$, P<0.001). On the other hands, the degree of correlation between shell length and shell height (SH) or shell width (SW) at Station 11 (SH: $R^2=0.91$, P<0.001; SW: $R^2=0.69$, P<0.001) was higher than that at Station 13 (SH: $R^2=0.64$, P<0.001; SW: $R^2=0.48$, P<0.001). In addition, fatness index of C. japonica at Station 13 was significantly (P < 0.001) higher than that at St. 11 (t-test value=-22.8, p<0.001). This implies that C. japonica at Station 13 might have enhanced their somatic growth, whereas C. japonica at Station 11 might have this kind of defense mechanism their internal organization against the salinity stress. Ecologically, this kind of defense mechanism of C. japonica against salinity flucuation may play an important role in their survival strategy.

• Journal of Plant Biotechnology
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• v.39 no.2
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• pp.106-113
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• 2012

Glycolysis is responsible for the conversion of glucose into pyruvate and for supplying reducing power and several metabolites. Fructose-1,6-bisphosphate aldolase (AtFBA1), a central enzyme in the glycolysis pathway, was isolated by functional complementation of the salt-sensitive phenotype of a calcineurin (CaN)-deficient yeast mutant. Under high salinity conditions, aldolase activity and the concentration of NADH were compromised. However, expression of AtFBA1 maintained aldolase activity and the NADH level in yeast cells. AtFBA1 shares a high degree of sequence identity with known class I type aldolases, and its expression was negatively regulated by stress conditions including NaCl. The fusion protein GFP-AtFBA1 was localized in the cytosol of Arabidopsis protoplasts. The seed germination and root elongation of AtFBA1 knock-out plants exhibited sensitivity to ABA and salt stress. These results indicate that AtFBA1 expression and aldolase activity is important for stress tolerance in yeast and plants.

• ALGAE
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• v.26 no.1
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• pp.3-20
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• 2011

The physiology of the unicellular green alga Dunaliella salina in response to abiotic stress has been studied for several decades. Early D. salina research focused on its remarkable salinity tolerance and ability, upon exposure to various abiotic stresses, to accumulate high concentrations of $\beta$-carotene and other carotenoid pigments valued highly as nutraceuticals. The simple life cycle and growth requirements of D. salina make this organism one of the large-scale commercially exploited microalgae for natural carotenoids. Recent advances in genomics and proteomics now allow investigation of abiotic stress responses at the molecular level. Detailed knowledge of isoprenoid biosynthesis mechanisms and the development of molecular tools and techniques for D. salina will allow the improvement of physiological characteristics of algal strains and the use of transgenic algae in bioreactors. Here we review D. salina isoprenoid and carotenoid biosynthesis regulation, and also the biotechnological and genetic transformation procedures developed for this alga that set the stage for its future use as a production system.

• 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 the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.692-697
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• 2016

This study examined the effects of salinity and medium used on the induction of sexual reproduction for the mass production of the resting eggs in the marine rotifer Brachionus rotundiformis for 9 days. After exposure to various salinities, the mixis rate in all treatments began to increase on the third day and decreased after the 4th or 5th day. The resting eggs appeared on the 4th day at 10‰, 15‰, 20‰, 25‰. In particular, the fertilization rates with 33.3% and 31.3% at 20‰ and 25‰ on day 6 were higher than those of the others, respectively. Mean mixis rate for 9 day at 0‰ and 20‰ were the highest with 25.3% and 20.2%, respectively, and the fertilization rate (14.0%) at 25‰ was the highest. In the medium experiment used, the mixis rate in all treatments were similar to the results of the salinity experiment. The resting eggs were only found at 0% and 25% of the used medium treatments. While there were no significant differences in the mean fertilization rate of all treatments, the mean mixis rate (22.3%) in the 25% treatment was higher than that of the control (0% treatment). As a result, salt stress was more effective than using the used medium to induce sexual reproduction in B. rotundiformis. The optimal salinity was considered to be 20-25‰, which caused a high mixis and fertilization rate in the rotifer. These results provide basic data for the mass production of rotifer resting eggs.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.323-333
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• 2015

As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs) functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs) or resistance (R) proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER) HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.5
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• pp.325-331
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• 2005

Seedlings of two rice genotyopes, cvs. Ilpumbyeo and Gancheokbyeo, were exposed to 0, 50 and 100 mM NaCl in nutrient solution for nine days. Plants were collected at the interval of 3 days and organic and inorganic solutes in leaves and roots and antioxidative enzyme activity in leaves were determined. Under salinity, the accumulation of soluble sugars occurred considerably in the older leaves of stressed seedlings compared to younger leaves and roots. The endogenous Na+ contents markedly increased at higher NaCl concentration in leaves and roots of seedlings, though it was higher accumulated in roots. Salinity resulted in an excessive proline accumulation in the stressed plants. A more pronounced increase was observed in Gancheokbyeo leaves. SOD activity in Impumbyeo cannot found any remarkable change, whereas, in Gancheokbyeo, its activity was rapidly decreased. CAT and POD activities increased with an increase in NaCl concentration in both genotypes. In sum­mary, the high capacity of rice seedlings to overcome an unfavorable growth condition such salt stress appears to be related to an adequate partition of organic solutes between shoots and roots and to changes in absorption, transport and re-translocation of salts.

• Korean Journal of Environmental Biology
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• v.34 no.2
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• pp.97-106
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• 2016

$Na^+/K^+$-ATPase is a membrane protein and plays a key role in osmotic regulation in living organisms. In the present study, a cDNA sequence encoding the $Na^+/K^+$-ATPase alpha subunit from the monogonont rotifer, Brachionus koreanus was cloned by rapid amplification of cDNA ends technique. To investigate the role of this enzyme in osmotic stress, enzymatic activities of $Na^+/K^+$-ATPase were measured after exposure to different salinities for 48 h. The full-length Bk $Na^+/K^+$-ATPase cDNA was 3069 bp-long, encoding a 1022-amino acid polypeptide. Bk $Na^+/K^+$-ATPase possesses eight membrane spanning regions and five conserved domains. Phylogenetic analysis showed that Bk $Na^+/K^+$-ATPase had high identity with those of other species, and was closely clustered with other Brachionus sp. These findings indicate that this protein was conserved both structurally and functionally. B. koreanus $Na^+/K^+$-ATPase activity was stimulated in both hyposaline (6 psu) and hypersaline (32 psu) conditions, suggesting that this protein may play a role in osmoregulation. This study would provide better understanding of the physiology of B. koreanus and this enzyme may be useful as a molecular marker for evaluation of osmotic stress in aquatic environment.