• Journal of Applied Biological Chemistry
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• v.60 no.3
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• pp.265-269
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• 2017

Environment-friendly, commercially-available agricultural products were investigated for antimicrobial activity against Sclerotinia sclerotiorum, as a pathogen of sclerotium disease. Then ${\beta}$-thujaplicin from Chamaecyparis obtuse was investigated for antifungal activity against six kinds of pathogenic fungi. It showed a statistically significant (p <0.001) growth inhibition effect on Sclerotinia sclerotiorum as a pathogen of sclerotium disease, Rhizoctonia solani AG-4 as a pathogen of damping off, Phytophthora capsici as a pathogen of phytophthora blight, and Colletotrichum coccodes as a pathogen of anthracnose at a concentration of 50 ppm and on Stemphylium solani as a pathogen of spotting disease and Alternaria alternata as a pathogen of black mold at a concentration of 100 ppm. In conclusion, these results indicate that it may be possible to develop environment-friendly agricultural products using ${\beta}$-thujaplicin compounds.

• Korean journal of food and cookery science
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• v.21 no.1 s.85
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• pp.47-52
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• 2005

This study aimed to determine inhibitory effect of pathogen growth by adding green tea extracts to some cook-chill foods. For this study, chicken meat salad and pyeonyuk were blended with green tea extracts to different concentrations of 0, 2 and $3\%$ and prepared in a cook-chill system. S. typhimurium in chickien meat salad; Better antibacterial effects of green tea extracts were observed at a $3\%$ concentration, compared with a $2\%$ concentration. Populations of S. aureus in chicken meat salad; antibacterial effects at a $3\%$ concentration became significant from 3days while that at a $2\%$ concentration remained steady throughout the five-day duration. All three testing samples exhibited a decrease in populations of S. aureus during storage. In pyeonyuk, S. aureus counts at a $3\%$ concentration were 7.26 CFU/g on day 3 and declined to 6.61 CFU/g and 6.48 CFU/g on the following days, showing a greater degree of decline than that of a $2\%$ concentration.

• Molecules and Cells
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• v.22 no.3
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• pp.336-342
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• 2006

Real time reverse transcription (RT)-PCR was used to quantify the expression of the botulinum neurotoxin type A (BoNT/A) gene (cntA) by normalization with the expression of 16S rRNA. The method were confirmed by monitoring the mRNA levels of cntA during growth in five type A strains. In all but one of the strains the expression of cntA mRNA was maximal in the late exponential phase, and approximately 35-fold greater than in the early exponential phase. The concentration of the extracellular BoNT/A complex detected by ELISA was highest in stationary phase. Sodium nitrite and sorbic acid completely inhibited growth at 20 ppm and $4mg\;ml^{-1}$, respectively. CntA expression became lower in proportion to the concentration of sorbic acid, and this reduction was confirmed by mouse bioassay. Our results show that real time RT-PCR can be used to quantify levels of C. botulinum type A neurotoxin transcripts and to assess the effects of food additives on botulinal risk.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.256-262
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• 2009

The potential of. nonpathogenic Fusarium oxysporum strain Avr5, either alone or in combination with chitosan and Bion, for inducing defense reaction in tomato plants inoculated with F. oxysporum f. sp lycopersici, was studied in vitro and glasshouse conditions. Application Bion at concentration of 5, 50, 100 and $500{\mu}g$/ml, and the highest concentration of chitosan reduced in vitro growth of the pathogen. Nonpathogenic F. oxysporum Avr5 reduced the disease severity of Fusarium wilt of tomato in split plants, significantly. Bion and chitosan applied on tomato seedlings at concentration $100{\mu}g$ a.i./plant; 15, 10 and 5 days before inoculation of pathogen. All treatments significantly reduced disease severity of Fusarium wilt of tomato relative to the infected control. The biggest disease reduction and increasing tomato growth belong to combination of nonpathogenic Fusarium and Bion. Growth rate of shoot and root markedly inhibited in tomato plants in response to tomato Fusarium wilt as compared with healthy control. These results suggest that reduction in disease incidence and promotion in growth parameters in tomato plants inoculated with nonpathogenic Fusarium and sprayed with elicitors could be related to the synergistic and cooperative effect between them, which lead to the induction and regulation of disease resistance. Combination of elicitors and non-pathogenic Fusarium synergistically inhibit the growth of pathogen and provide the first experimental support to the hypothesis that such synergy can contribute to enhanced fungal resistance in tomato. This chemical could provide a new approach for suppression of tomato Fusarium wilt, but its practical use needs further investigation.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.491-495
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• 1998

A fungal disease of the cultivated mushroom, Ganoderma lucidum, caused by Xylogone sphaerospora was epidemic throughout all cultivation areas in Korea which caused a lot of yield losses in the mushroom production. For controlling the disease, the screening of effective fungicides against the pathogenic fungus were conducted. Thirty seven commercially available fungicides were tested for their inhibitory activities on potato dextrose agar media supplemented with these fungicides at various concentrations. Twenty one fungicides significantly inhibited mycelial growth of the pathogen, Xylogone sphaerospora, but 16 fungicides had no inhibitory effect. Among these 21 fungicides, 17 fungicides also inhibited mycelial growth of Ganoderma lucidum as well, but imazalil, procymidone, triforine, and vinclozolin had no inhibitory effects. However, vinclozolin showed no inhibitory effect on mycelial growth of the mushroom even at the concentration of 50 $\mu\textrm{g}$/ml vinclozolin solution for 2 hours, and then the pathogen was inoculated. After two month-cultivation of the mushroom, over 90% of logs treated with vinclozolin without pathogen inoculation produced fruiting bodies. However, fruiting bodies were not produced form the logs inoculated with the pathogen, but not treated with vinclozolin. Fifty seven percent of logs. which were pre-treated with vinclozolin and then inoculated with the pathogen produced fruiting bodies. Based on the results, vinclozolin is effective for the control of yellow disease of the Ganoderma lucidum caused by Xylogone sphaerospora.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.1
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• pp.37-44
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• 2007

To investigate the response of proline and ammonia to pathogen infection, plant growth and relevant chemical component were examined in large patch-infected or healthy (control) zoysiagrass during 6 days after treatment. Pathogen-infection increased root mortality by 30% compared to control. Soluble protein was not significantly affected by pathogen-infection except in the leaf at day 6. Ammonia concentration also increased significantly in both leaves and roots of pathogen-infected plants. Proline concentration in leaves and roots increased to 3.4- and 4.5-fold, respectively, compared to those of control at day 6. These results suggest that proline accumulation may be a sensitive biochemical indicator representing the stress intensity caused by pathogen infection in zoysiagrass.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.1-9
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• 2019

Background: Korean ginseng is an important cash crop in Asian countries. However, plant yield is reduced by pathogens. Among the Ilyonectria radicicola-species complex, I. mors-panacis is responsible for root-rot and replant failure of ginseng in Asia. The development of new methods to reveal the existence of the pathogen before cultivation is started is essential. Therefore, a quantitative real-time polymerase chain reaction method was developed to detect and quantify the pathogen in ginseng soils. Methods: In this study, a species-specific histone H3 primer set was developed for the quantification of I. mors-panacis. The primer set was used on DNA from other microbes to evaluate its sensitivity and selectivity for I. mors-panacis DNA. Sterilized soil samples artificially infected with the pathogen at different concentrations were used to evaluate the ability of the primer set to detect the pathogen population in the soil DNA. Finally, the pathogen was quantified in many natural soil samples. Results: The designed primer set was found to be sensitive and selective for I. mors-panacis DNA. In artificially infected sterilized soil samples, using quantitative real-time polymerase chain reaction the estimated amount of template was positively correlated with the pathogen concentration in soil samples ($R^2=0.95$), disease severity index ($R^2=0.99$), and colony-forming units ($R^2=0.87$). In natural soils, the pathogen was recorded in most fields producing bad yields at a range of $5.82{\pm}2.35pg/g$ to $892.34{\pm}103.70pg/g$ of soil. Conclusion: According to these results, the proposed primer set is applicable for estimating soil quality before ginseng cultivation. This will contribute to disease management and crop protection in the future.

• The Plant Pathology Journal
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• v.16 no.1
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• pp.19-24
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• 2000

The direct effects of acute $\textrm{O}_3$ on the growth, sporulation and infection of Pyricularia grisea, rece blast pathogen, were investigated to understand the interactions between ozone and the pathogen. Acute exposure of 200 nl $\textrm{l}^{-1}$ ozone for 8 h significantly reduced conidia germination on water atar. Ozone exposure of 200 nl $\textrm{l}^{-1}$ for 8h per day for 5 days had no effect on increase in colony diameter, but severely damaged actively growing aerial mycelia. However, the damage to mycalia was recovered during the following 16 h exposure of unpolluted air. Conidial production was also stimulated by the acute ozone exposure for 5 days. The conidia exposed to the acute ozone for 5 days normally germinates but slightly reduce appressoria formation on rice leaf. However, the conidia produced by artificial stimulation under the same ozone concentration for 10 days showed significant reduction in appressorea for mation on a hydrophobic film. This study suggests that the acute ozone could ingibit appressoria formation as well as vegetative growth of the pathogen, resulting in decrease in rece blast development in the field during summer when high ozone episodes could occur occasionally.

• Journal of Ginseng Research
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• v.38 no.2
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• pp.136-145
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• 2014

Background: This study aimed to develop a biocontrol system for ginseng root rot caused by Fusarium cf. incarnatum. Methods: In total, 392 bacteria isolated from ginseng roots and various soils were screened for their antifungal activity against the fungal pathogen, and a bacterial isolate (B2-5) was selected as a promising candidate for the biocontrol because of the strong antagonistic activity of the bacterial cell suspension and culture filtrate against pathogen. Results: The bacterial isolate B2-5 displayed an enhanced inhibitory activity against the pathogen mycelial growth with a temperature increase to $25^{\circ}C$, produced no pectinase (related to root rotting) an no critical rot symptoms at low [$10^6$ colony-forming units (CFU)/mL] and high ($10^8CFU/mL$) inoculum concentrations. In pot experiments, pretreatment with the bacterial isolate in the presumed optimal time for disease control reduced disease severity significantly with a higher control efficacy at an inoculum concentration of $10^6CFU/mL$ than at $10^8CFU/mL$. The establishment and colonization ability of the bacterial isolates on the ginseng rhizosphere appeared to be higher when both the bacterial isolate and the pathogen were coinoculated than when the bacterial isolate was inoculated alone, suggesting its target-oriented biocontrol activity against the pathogen. Scanning electron microscopy showed that the pathogen hyphae were twisted and shriveled by the bacterial treatment, which may be a symptom of direct damage by antifungal substances. Conclusion: All of these results suggest that the bacterial isolate has good potential as a microbial agent for the biocontrol of the ginseng root rot caused by F. cf. incarnatum.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.2
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• pp.129-136
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• 2007

To investigate the effect of large patch infection on oxidative stress induction, growth, $H_2O_2$ concentration and lipid peroxidation were compared between pathogen-infected and healthy (control) zoysiagrass. The sampling for leaves and roots were carried out every 2 days for a period of 6 days. Pathogen-infection increased root mortality by 30% compared to control. Dry mass was not significantly affected by pathogen-infection until day 4, but significant decreases in both leaves (-14%) and roots (-20%) were observed at day 6. The $H_2O_2$ concentration in pathogen-infected leaves rapidly increased within the first 2 days(+28%) and then slightly decreased. The increase of $H_2O_2$ in pathogen-infected roots was distinct, showing 1.7-fold higher level than control at day 6. The extent of lipid peroxidation caused by pathogen-infection continuously increased for the first 4 days. This was then stagnated until day 6. In roots, the significant increase of lipid peroxidation was observed only at day 2. These results indicate that large patch-infection induces oxidative stress, and that the oxidative stress responsive pattern was plant organ specific.