• The Korean Journal of Mycology
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• v.50 no.4
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• pp.319-329
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• 2022

In July 2020, wilting symptoms were observed among adzuki bean plants (Vigna angularis var. angularis L.) in the fields in Yeosu, Korea. Infected plants showed yellowing of leaves, browning inside the stems, splitting of stem bark, and wilting. When these plants were uprooted, their roots were found to be brown. The fungal pathogens NC20-737, NC20-738, and NC20-739 were isolated from symptomatic stem and root tissues. These pathogens were identified as a Fusarium fujikuroi species complex based on their morphological characteristics. Molecular identification was performed using the DNA sequence of translation elongation factor 1 alpha and the RNA polymerase II second largest subunit regions. The nucleotide sequences of all three isolates were similar to the F. fujikuroi reference isolates NRRL 13566 and NRRL 5538 of the National Centre for Biotechnology Information GenBank. A pathogenicity test was conducted by the soil inoculation method with cornmeal sand inoculum. Approximately 3 weeks after inoculation, symptoms were observed only in the inoculated adzuki bean seedlings. To the best of our knowledge, this is the first report of Fusarium root rot caused by F. fujikuroi in adzuki beans, both in Korea and worldwide.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.141-148
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• 1992

Field experiment was carried out to investigate the effect of plant growth regulator (PGR); IAA, GA, Kinetin to regrowth of sorghum and pearlmillet according to variety and plant growth stage. Kinetin application after cut increased tiller number and decreased dry weight of regrowth, but its application on sorghum stubble in water stress increased tiller number and leaf elongation rate, consequently increased regrowth dry weight. GA application reduced tiller production in both species, but tiller formation in pearlmillet was decreased more than in sorghum by promoting leaf elongation of old tiller. Nonstructural carbohydrate (NSC) of stubble during regrowth was consumed less at anthesis than at stem elongation stage because of senescence of tiller primordia. GA treatment reduced NSC content more than other PGR in both plant species, by consuming reserve NSC and stimulating rapid elongation of old tiller after cut. Dry matter increase during regrowth had high correlation with tiller number and tiller elongation a week after cut, while it did not have any correlation with NSC at cutting stage or with consumption of NSC during regrowth. Therefore, regrowth in sorghum and pearmillet must depend upon activity of tiller primordia more than upon amount of reserved NSC.

• Korean Journal of Medicinal Crop Science
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• v.10 no.4
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• pp.259-262
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• 2002

The efficiency of regeneration of callus and explants from leaf and stem disks of Epimedium koreanum was examined on the MS media containing 2,4-D, NAA, Kinetin, BA and TDZ. Calli were formed on the 2mg/l 2,4-D media at the rate of 32% from leaf discs and 52% from stems. No callus was produced on the media which are containing BA or TDZ alone. The combination of 2,4-D and BA showed the effect on the formation of callus. The combination of 2mg/l 2,4-D and 0.lmg/l BA in the MS media had produced the highest percentage of callus formation, 50% from leaf discs and 40% from stems, respectively. The combination of 2mg/l 2,4-D and 1mg/1 BA in the MS media had affected the formation of callus in the rate of 40% from leaf discs and 25% from stems. The combined plant growth regulators of 2,4-D and BA increased the formation of calli from leaf discs, but single treatment of 2,4-D showed the highest callus formation from stems. Multiple shoots from leaf discs were formed on the media containing NAA, BA, kinetin, and TDZ. The highest number of multiple shoots were obtained 0.1mg/l NAA combined with 1mg/l kinetin. As a result, leaf discs or stems can be used for the mass propagation of Epimedium koreanum, but stem elongation of shoots from calli was not easy.

• The Plant Pathology Journal
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• v.33 no.3
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• pp.249-263
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• 2017

This study aims to examine the potential reasons for the current prevalence of the fusarium wilt in the oriental melon. Twenty-seven Fusarium isolates obtained from oriental melon greenhouses in 2010-2011 were identified morphologically and by analysis of elongation factor-1 alpha gene (EF-$1{\alpha}$) and internal transcribed spacer (ITS) rDNA sequences as 6 Fusarium species (8 isolates of F. oxysporum, 8 F. commune, 5 F. proliferatum, 3 F. equiseti, 2 F. delphinoides, and 1 F. andiyazi), which were classified as same into 6 EF-$1{\alpha}$ sequence-based phylogenetic clades. Pathogenicity of the Fusarium isolates on the oriental melon was highest in F. proliferatum, next in F. oxysporum and F. andiyazi, and lowest in the other Fusarium species tested, suggesting F. proliferatum and F. oxysporum were major pathogens of the oriental melon, inducing stem rots and vascular wilts, respectively. Oriental melon and watermelon were more susceptible to F. oxysporum than shintosa and cucumber; and cucumber was most, oriental melon and watermelon, medially, and shintosa was least susceptible to F. proliferatum, whose virulence varied among and within their phylogenetic subclades. Severe root-knot galls were formed on all the crops infected with Meloidogyne incognita; however, little indication of vascular wilts or stem and/or root rots was shown by the nematode infection. These results suggest the current fungal disease in the oriental melon may be rarely due to virulence changes of the fusarium wilt pathogen and the direct cause of the severe root-knot nematode infection, but may be potentially from other Fusarium pathogen infection that produces seemingly wilting caused by severe stem rotting.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.236-241
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• 2014

An efficient regeneration protocol for stem disc culture of Populus euramericana, which is important species for bioenergy resource in agroforestry, was established. The number of explants that were obtained and the number of explants that regenerated varied with the genotypes. However, in all the genotypes, stem disc culture produced more regenerated shoots than did in axillary bud culture. A comparison of the effects of cytokinin type and concentration on shoot regeneration in different explants (i.e., petiole, leaf, and root segments of P. euramericana) revealed that a concentration of $0.002mg\;l^{-1}$ thidiazuron (TDZ) used on petiole segments resulted in the greatest shoot regeneration (95.83%). The hormonal requirements for the greatest shoot regeneration in the three explant types varied. Different concentrations of $AgNO_3$ and $CoCl_2$ were added separately to the medium to stop the yellowing and subsequent necrosis of the regenerated shoots. Lower concentrations (3 and $5mg\;l^{-1}$) of these compounds improved shoot regeneration and elongation, compared with the control. The in vitro-regenerated shoots were transferred to rooting medium and subsequently acclimatized. The highly efficient regeneration system of P. euramericana reported here can be used for mass propagation of this recalcitrant for regeneration, economically important tree species.

• Tissue Engineering and Regenerative Medicine
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• v.15 no.6
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• pp.751-760
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• 2018

BACKGROUND: Bone tissue engineering based on pluripotent stem cells (PSCs) is a new approach to deal with bone defects. Protocols have been developed to generate osteoblasts from PSCs. However, the low efficiency of this process is still an important issue that needs to be resolved. Many studies have aimed to improve efficiency, but developing accurate methods to determine efficacy is also critical. Studies using pluripotency to estimate efficacy are rare. Telomerase is highly associated with pluripotency. METHODS: We have described a quantitative method to measure telomerase activity, telomeric repeat elongation assay based on quartz crystal microbalance (QCM). To investigate whether this method could be used to determine the efficiency of in vitro osteogenic differentiation based on pluripotency, we measured the pluripotency pattern of cultures through stemness gene expression, proliferation ability and telomerase activity, measured by QCM. RESULTS: We showed that the pluripotency pattern determined by QCM was similar to the patterns of proliferation ability and gene expression, which showed a slight upregulation at the late stages, within the context of the general downregulation tendency during differentiation. Additionally, a comprehensive gene expression pattern covering nearly every stage of differentiation was identified. CONCLUSION: Therefore, this assay may be powerful tools for determining the efficiency of differentiation systems based on pluripotency. In this study, we not only introduce a new method for determining efficiency based on pluripotency, but also provide more information about the characteristics of osteogenic differentiation which help facilitate future development of more efficient protocols.

• The Korean Journal of Ecology
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• v.15 no.2
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• pp.173-180
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• 1992

Pb, Zn tolerance of phaseolus multiflorus was investigated, based on the elongation of root and stem, pollen Germination and progeny quality in various pb, zn concentrations. The result obtained by water culture showed that the growth of roots and steams of phaseolus multiflorus from pb-zn mine site is less inhivited than that of the control site. The flower of phaseolus multiflorus from which pollen was taken were grown without added pb, zn and percent germination of pollen observed in a range of pb, zn concentrations. The percent germination of pollen from pb-zn mine site was higher than the control site. phaseolus multiflorus collected at a pb-zn mine site and the control site was site were grown at different pb, zn concentrations, its progeny was retreated with same concentrations of pb-zn mine site was more vigorous than the control site. thus, pb-zn tolerance was able to expressed in both pollen and sporophytes.

• Korean Journal of Medicinal Crop Science
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• v.10 no.4
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• pp.249-252
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• 2002

Several plant growth regulators were examined for on their effect on the in vitro propagation of Kalopanax pictus$(T_{HUNB}.)$ $(N_{AKAI}.)$ on WPM medium. Among the cytokinins tested, BA at $13.32\;{\mu}M$ appeared to be the most effective for multiple axillary shoot formation. Although the addition of $2.89\;{\mu}M\;GA_3$ promoted stem elongation, it produced morphologically abnormal leaves and stems. For rooting of the shoots, $4.9\;{\mu}M$ IBA seemed to be more effective than $2.69\;{\mu}M$ NAA. When the regenerated plants were transferred on artificial mixture containing vermiculite and peat-moss (1 : 1, v/v), 81% of them survived and grew normally.

• Journal of Plant Biology
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• v.36 no.3
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• pp.251-257
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• 1993

The size variation of the cambial initials and their derivatives, in relation to the increase of girth, in the intact and decapitated stem of Populus euramericana was anatomically studied. In the typical nonstoried cambium of P. euramericana, the cell size of fusiform initials, vessel member, and sieve tube member were gradually increased and thus it reached a maximal state. In the intact plants, the size of the cambial initials and their derivatives was larger then in the decapitated ones. On the other hand, the frequency of anticlinal division of the cambial cells, the rate of the elongation and loss of the daughter initials in the intact plants was higher than in the decapitated ones. The cambium of the intact plants had higher ray compared with that of the decapitated ones. It was interpreted that these results were caused by the decapitation, which could block the supply of certain substances for cell growth such as hormones and metabolites.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2017.11a
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• pp.46-47
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• 2017