• BMB Reports
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• v.52 no.11
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• pp.653-658
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• 2019

MYB-type transcription factors (TFs) play important roles in plant growth and development, and in the rapid responses to unfavorable environmental conditions. We recently reported the isolation and characterization of a rice (Oryza sativa) MYB TF, OsMYB102, which is involved in the regulation of leaf senescence by downregulating abscisic acid (ABA) biosynthesis and the downstream signaling response. Based on the similarities of their sequences and expression patterns, OsMYB102 appears to be a homolog of the Arabidopsis thaliana AtMYB44 TF. Since AtMYB44 is a key regulator of leaf senescence and abiotic stress responses, it is important to examine whether AtMYB44 homologs in other plants also act similarly. Here, we generated transgenic Arabidopsis plants expressing OsMYB102 (OsMYB102-OX). The OsMYB102-OX plants showed a delayed senescence phenotype during dark incubation and were more susceptible to salt and drought stresses, considerably similar to Arabidopsis plants overexpressing AtMYB44. Real-time quantitative PCR (RT-qPCR) revealed that, in addition to known senescence-associated genes, genes encoding the ABA catabolic enzymes AtCYP707A3 and AtCYP707A4 were also significantly upregulated in OsMYB102-OX, leading to a significant decrease in ABA accumulation. Furthermore, protoplast transient expression and chromatin immunoprecipitation assays revealed that OsMYB102 directly activated AtCYP707A3 expression. Based on our findings, it is probable that the regulatory functions of AtMYB44 homologs in plants are highly conserved and they have vital roles in leaf senescence and the abiotic stress responses.

• Journal of Plant Biotechnology
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• v.48 no.4
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• pp.246-254
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• 2021

Environmental stresses are estimated to have reduced global crop yields of wheat by 5.5%. However, traditional approaches for the transfer of resistance to these stresses in wheat plants have yielded limited results. In this regard, genetic transformation has undoubtedly opened up new avenues to overcome crop losses due to various abiotic stresses. Particle bombardment has been successfully employed for obtaining transgenic wheat. However, most of these procedures employ immature embryos, which are not available throughout the year. Therefore, the present investigation utilized mature seeds as the starting material and used the calli raised from three Moroccan durum wheat varieties as the target tissue for genetic transformation by the biolistic approach. The pANIC-5E plasmid containing the SINA gene for drought and salinity tolerance was used for genetic transformation. To enhance the regeneration capacity and transformation efficiency of the tested genotypes, the study compared the effect of copper supplementation in the induction medium (up to 5 μM) with the standard MS medium. The results show that the genotypes displayed different sensitivities to CuSO₄, indicating that the transformation efficiency was highly genotype-dependent. The integration of transgenes in the T₀ transformants was demonstrated by polymerase chain reaction (PCR) analysis of the obtained resistant plantlets with primers specific to the SINA gene. Among the three genotypes studied, 'Isly' showed the highest efficiency of 9.75%, followed by 'Amria' with 1.25% and 'Chaoui' with 1%.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.240-249
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• 2022

Measuring chlorophyll fluorescence (CF) is a useful tool for assessing a plant's ability to tolerate abiotic stresses such as drought, waterlogging and high temperature. Korean ginseng is highly sensitive to water stress in paddy fields. To evaluate the possibility of non-destructively diagnosing waterlogging stress using chlorophyll fluorescence (CF) imaging techniques, we screened 57 ginseng accessions for waterlogging tolerance. To evaluate waterlogging tolerance among the 2-year-old Korean ginseng accessions, we treated ginseng plants with water stress for 25 days. The physiological disorder rate was characterized through visual assessment (an assigned score of 0-5). The physiological disorder rates of Geumjin, Geumsun and GS00-58 were lower than that of other accessions. In contrast, lines GS97-62, GS97-69 and GS98-1-5 were deemed susceptible. Root traits, chlorophyll content and the reduction rates decreased in most ginseng accessions. Further, these metrics were significantly lower in susceptible genotypes compared to resistant ones. All CF parameters showed a positive or negative response to waterlogging stress, and this response continuously increased over the treatment time among the genotypes. The CF parameter Fv/Fm was used to screen the 57 accessions, and the results showed clear differences in Fv/Fm between the susceptible and resistant genotypes. Susceptible genotypes had an especially low Fv/Fm value of less than 0.8, reflecting damage to the reaction center of photosystem II. It is concluded that Fv/Fm can be used as a CF parameter index for screening waterlogging stress tolerance in ginseng genotypes.

• Korean Journal of Organic Agriculture
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• v.26 no.2
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• pp.217-232
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• 2018

Drought is a major obstacle to high agricultural productivity, worldwide. In drought, it is usually presented by the simultaneous action of high temperature and drying. Also there are negative effects of plant growth under drying conditions. In this study, the effect of Bacillus velezensis YP2 on plant growth-promotion and soil drying stress tolerance of kale plants, Brassica oleracea var. alboglabra Bailey, were investigated under two different conditions; greenhouse and field environments. Root colonization ability of B. velezensis YP2 was also analysed by using plating culture method. As a result of the greenhouse test, the YP2 strain significantly promoted the growth of kale seedlings in increasement of 26.7% of plant height and 142.2% of shoot fresh weight compared to control. B. velezensis YP2 have the mitigation effect of drying injury of kale by decreasing of 39.4% compared to control. In the field test, B. velezensis YP2 strain was also found to be effective for plant growth-promotion and mitigation of drying stress injury on kale plants. Especially, relative water contents (RWC; %) were higher in B. velezensis YP2 treated kales than in control at 7, 10, 14 day after non-watering. The root colonization ability of YP2 strain was continued at least for 21 days after soil drenching treatment of B. velezensis YP2. Our result suggested that enhancement of plant growth and drying injury reduction of kale plants were involved in kale root colonization by B. velezensis YP2, which might be contributed to increasing water availability of plants. Consequentially, the use of B. velezensis YP2 might be a beneficial influence for improving productivity of kale plants under drying stress conditions.

• Journal of Korean Society of Forest Science
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• v.61 no.1
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• pp.8-14
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• 1983

This study was to diagnose the ontogenetic ability of drought tolerance in trees, and was to investigate the seasonal changes in tissue-water relations parameters, ${\pi}_o$, ${\pi}_p$, $E_{max}$, $N_s/DW$, $V_o/W_s$ and $RWC_{(tlp)}$, obtained from P-V curves on the Pinus koraiensis and Abies holophylla shoots. The results obtained are as follows; 1) Seasonal changes of original osmotic pressure at maximum turgot, ${\pi}_o$, were -1.2 to -1.6 MPa in Pinus koraiensis and -1.4 to -1.7 MPa in Abies holophylla. 2) Seasonal changes of osmotic pressure at incipient plasmolysis, ${\pi}_p$, were -1.8 to -2.1 MPa in Pinus koraiensis and -1.6 to -2.1 MPa in Abies holophylla. 3) Seasonal changes of relative water content at incipient plasmolysis, $RWC_{(tlp)}$, were 70 to 77% in Pinus koraiensis and 69 to 85% in Abies holophylla. 4) Seasonal changes of maximum bulk modulus of elasticity at maximum hydration, $E_{max}$, were 2.2 to 6.3 MPa in Pinus koraiensis and 3.1 to 7.9 MPa in Abies holophylla. 5) Seasonal changes of number of osmoles of solute in symplasm versus dry weight, $N_s/DW$, were 0.5 to 1.3 in Pinus koraiensis and 0.3 to 1.0 in Abies holophylla. 6) Seasonal changes of original osmotic water volume versus total water volume (symplasmic and apoplastic water), $V_o/W_s$, were 55 to 65%r in Pinus koraiensis and 40 to 65% in Abies holophylla. Consequently, as the comparative values of ${\pi}_o$, ${\pi}_p$, $E_{max}$, $N_s/DW$, $V_o/W_s$, and $RWC_{(tlp)}$, it might be suggested that Abies holophylla shoot could have more or less a greater ability of drought tolerance as compared with Pinus koraiensis shoot.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.1
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• pp.117-123
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• 2011

This study aims to suggest a suitable soil thickness and soil mixture ratio of a green roof system by verifying the growth of Chrysanthemum zawadskii var. coreanum as affected by different green roof systems using rainwater. The experimental planting grounds were made with different soil thicknesses(15cm, 25cm) and soil mixing ratios (SL, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$) and with excellent drought tolerance. Ornamental value Chrysanthemum zawadskii var. coreanum was planted. The change in plant height, green coverage ratio, chlorophyll content, fresh weight, dry weight, and dry T/R ratio of Chrysanthemum zawadskii var. coreanum were investigated from April to October 2009. For 15cm soil thickness, the plant height of Chrysanthemum zawadskii var. coreanum was not significantly different as affected by the soil mixing ratio. However, it was found to be higher in the amended soil mixture, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ and $P_4P_4L_2$ than in the sandy loam soil, as it was SL overall. For 25cm soil the plant height differences were in order to SL < $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ < $P_4P_4L_2$. The green coverage ratio was observed not to be different by soil mixing ratio with soil thickness of 15cm, but, the lowest green coverage ratio in the SL. In the 25cm soil thickness, the green coverage ratio was 86-89% with a good coverage rate overall. The change in chlorophyll contents with 15cm soil thickness was found to be the highest in the SL treatment and the lowest in the $P_5P_3L_2$ treatment. For 25cm thickness, the highest value was in the $P_4P_4L_2$ and SL, and the lowest in the$P_7P_1L_2$. Fresh weight and dry weight were larger in soil with 25cm thickness. Therefore, the growth of Chrysanthemum zawadskii var. coreanum as affected by a different green roof system for using rainwater was higher in soil with 25cm thickness than 15cm, and in PPL amended soil than in sandy loam.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.51-56
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• 2015

The objective of this study was to evaluate the effect of silicate fertilizer on growth, physiology and abiotic stress tolerance of Chinese cabbage seedlings. Five silicate concentrations (8, 16, 32, 64, and 128mM) and control (non-treatment) were applied to Chinese cabbage seedlings twice a week. Three weeks after application of silicate treatment, seedlings were used for treating abiotic stresses and were assessed for growth and physiological characteristics. Growth parameters significantly increased in 8, 16, and 32mM treatments except 64 and 128mM. Total root surface area, total root length, and number of root tips increased in 8, 16 and 32mM treatments, but they decreased in treated seedlings with 64 and 128mM of silicate. The highest growth parameters and root morphology were observed in 8mM treatment. As for the effect on the seedling physiology, transpiration rates decreased while stomatal diffusive resistance increased to increasing silicate concentration. The application of silicate reduced the electrical conductivity, heating and chilling injury index at high and low temperatures. Silicate enhanced drought tolerance of Chinese seedlings by delaying the starting time of wilting point. The starting time of wilting point in the control was 3 days after discontinuation of irrigation, while in the 8, 64 and 128mM of silicate treatments were 4 days, and the 16 and 32mM treatments were 5 days. All plants were wilted after 5 days in control without irrigation whereas it showed in 8mM treatment after 6 days, in 16, 32, 64, 128mM treatments after 7 days.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.69-75
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• 2017

Dormancy-associated protein (DRM) is involved in the dormancy physiology of plants and is conserved in almost all plant species. Recent studies found that DRM genes are involved in the abiotic stress response, and characterization studies of these genes have been conducted in several plants. However, few studies have focused on DRM genes in woody plants. Therefore, in this study, cDNA coding for DRM (PagDRM1) was isolated from poplar (Populus alba ${\times}$ P. glandulosa), and its structure and expression characteristics were investigated. PagDRM1 encodes a putative protein composed of 123 amino acids, and the protein contains two conserved domains (Domain I and Domain II). PagDRM1 is present as one or two copies in the poplar genome. Its expression level was highest in the stem, followed by mature leaves, roots, and flowers. During the growth of cultured cells in suspension, PagDRM1 was highly expressed from the late-exponential phase to the stationary phase. In addition, PagDRM1 expression increased in response to drought, salt stress, and treatment with plant hormones (e.g., abscisic acid and gibberellic acid). Therefore, we suggested that PagDRM1 not only plays an important role in the induction of dormancy, but also contributes to stress tolerance in plants.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.311-343
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• 2004

Various aspect of epidemics broke out continually from the middle of Joseon Dynasty due to the famine and drought caused by abnormal climate of the sixteenth century and the war. Thus the Dynasty performed sacrificial rites, isolated the patients and published plenty of medical books related epidemics in order to cure of the patients, and Heojun edited 『Byeokyeoksinbang』 as 'Dangdokyeok' broke out at Gwanbuk(關北) districts in 1613, Heojun explained the cause of Dangdokyeok as meteorology under the feudal conditions, and concluded Simhwa(心火) by fever toxin, Therefore he selected the method of puting out Simhwa by attack of fever toxin. In addition he presented emergency treatment that can maintain the airway by bleeding. To treat Dangdokyeok, Heojun presented lots of prescriptions so as Seungmagalgeuntang(升麻葛根湯), Cheongyeolhaedoksan(淸熱解毒散), Yeongyopaedok-san(連翹敗毒散), Bangpungtongsaongsan(防風通聖散), Jowiseunggitang(調胃升氣湯) and Hwangryeonhaedoktang(黃連解毒湯) etc. And he proposed Samdueum (三豆飮), Realgar(石雄黃) and so on to prevent infection from that. They presume from 120 to 150 years as the period of human adaptation to the first epidemics. Dangdokyeok put a large number of people to death at first, but it wasn't referred at the history any more after Byeokyeoksinbang. So we can say that the treatment of Heojun may be effective. Common cold and dyspeptic cold broke out in our country differently from 'Shanghan(傷寒)' in the China, so we had settled 'pestilence infectious epidemic disease(瘟疫)' while 'epidemic febrile disease(溫病)' of the China. Dangdokyeok of Heojun is similar to 'Scalet fever' belonging to 'virulent heat pathogen(溫毒)', 'newly epidemic febrile disease(新感溫病)'. As a cure of Dangdokyeok, the Korean medicine uses the treatment of removing fever state whereas the western medicine uses the antibiotics to kill the streptococcus. The symptoms of Dangdokyeok are remarkably similar to those of the Scarlatina, so this occupies a high position on the world history of medicine in aspects of the period and details of symptoms. These days we have the problems that the tolerance of antibiotics increases and disease of unknown cause is prevalent. It means the western medicine get to limits. So if we progress epidemiography based on Heojun's medicine, we may contribute to the world history of medicine.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.7-7
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• 2017

Unfavorable weather and soil conditions reduce rice yield and land and water productivity, aggravating existing encounters of poverty and food insecurity. These conditions are foreseen to worsen with climate change and with the unceasing irrational human practices that progressively debilitate productivity despite global appeals for more food. Our understanding of plant responses to abiotic stresses is advancing and is complex, involving numerous critical processes - each controlled by several genetic factors. Knowledge of the physiological and molecular mechanisms involved in signaling, response and adaptation, and in some cases the genes involved, is advancing. Moreover, the genetic diversity being unveiled within cultivated rice and its wild relatives is providing ample resources for trait and gene discovery, and this is being scouted for rice improvement using modern genomics and molecular tools. Development of stress tolerant varieties is now being fast-tracked through the use of DNA markers and advanced breeding strategies. Large numbers of drought, submergence and salt tolerant varieties were commercialized over recent years in South and Southeast Asia and more recently in Africa. These varieties are making significant changes in less favorable areas, transforming lives of smallholder farmers - progress considered incredulous in the past. The stress tolerant varieties are providing assurance to farmers to invest in better management of their crops and the ability to adjust their cropping systems for even higher productivity and more income, sparking changes analogous to that of the first green revolution, which previously benefited only favorable irrigated and rainfed areas. New breeding tools using markers for multiple stresses made it possible to develop more resilient, higher yielding varieties to replace the aging and obsolete varieties still dominating these areas. Varieties with multiple stress tolerances are now becoming available, providing even better security for farmers and lessening their production risks even in areas affected by complex and overlapping stresses. The progress made in these less favorable areas triggered numerous favorable changes at the national and regional levels in several countries in Asia, including adjusting breeding and dissemination strategies to accelerate outreach and enabling changes at higher policy levels, creating a positive environment for faster progress. Exploiting the potential of these less productive areas for food production is inevitable, to meet the escalating global needs for more food and sustained production systems, at times when national resources are shrinking while demand for food is mounting. However, the success in these areas requires concerted efforts to make use of existing genetic resources for crop improvement and establishing effective evaluation networks, seed production systems, and seed delivery systems to ensure faster outreach and transformation.