• 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.

• Journal of The Korean Society of Clinical Toxicology
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• v.20 no.2
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• pp.75-81
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• 2022

Purpose: This study sought to compare the characteristics of patients with pathogen-positive and negative cultures, and to investigate factors predicting pathogen-positive culture results in patients of acute poisoning with suspected aspiration. Methods: Consecutive patients with acute poisoning admitted to an intensive care unit between January 2016 and December 2018 were retrospectively studied. Respiratory specimens were collected from the enrolled patients at the time of the suspected aspiration. We compared the characteristics of patients with pathogen-positive and negative culture results and analyzed the causative pathogens. Results: Among the 526 patients, 325 showed no clinical features that could be attributed to aspiration, and 201 patients had clinical features suggestive of aspiration. Of these, 113 patients had pathogen-positive culture, 61 were negative, and the specimens of 27 patients contained poor-quality sputum. In univariate analysis, patients with a positive culture showed a longer time to culture from ingestion (p=0.01), faster heart rate (p=0.01), and higher partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO₂/FiO₂) (p=0.02) than patients with negative culture. Multivariate analysis demonstrated that PaO₂/FiO₂ (adjusted odd ratio, 1.005; 95% confidence interval [CI], 1.002-1.008; p=0.005) was a significant risk factor for pathogen-positive culture. The area under the receiver operating characteristic curve of PaO₂/FiO₂ was 0.591 (95% CI, 0.510-0.669, p=0.05). Gram-negative pathogens (GNPs) were predominant and at least one GNP was observed in 84 (73.3%) patients among those with pathogen positive culture. Conclusion: We failed to find any clinical factors associated with positive culture results. Antibiotics that cover GNPs could be considered when deciding the initial antibiotic regimen at the time of suspected aspiration.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.50-53
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• 2001

Severe crown gall disease was occurred in green house cultivating rose in Jinchen, Chungbuk recently. Although it causes problem on rose cultivation, the growers do not have many choices of control measures for the disease now. Agrobacterium radiobacter K84 has been known as a strong antagonist against A. tumefaciens, a pathogen causing crown gall disease, and used as a biopesticide for crown gall in many countries since it had been introduced in 1972. We tested control activity of A. radiobacter K84 for the crown gall disease on rose. Spray of A. radiobacter K84 suspension on above ground of rose either before or after pathogen spray reduced size and fresh weight of galls significantly. Size and fresh weight of galls on roses inoculated with pathogen either before A. radiobacter K84 spray (pathogen-K84 treatment) or after A. radiobacter K84 spray(K84-pathogen treatment) were 4 to 5% of those of galls on roses inoculated pathogen only. Disease incidence of plants inoculated pathogen only was 85% whereas disease incidence of pathogen-K84 or K84-pathogen treatments were 6.7% and 5.0% respectively. Dipping of roots of rose in suspension of A. radiobacter K84 was also reduced size of galls and diseased rate significantly. These results indicate that A. radiobacter K84 is effective in the prevention of gall formation by A. tumefaciens and it can be used to control of crown gall disease of rose.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.227-230
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• 2001

Bioassay techniques using young leaves and roots were developed to screen resistance of Atractylis spp. against Phytophthora drechsleri. Among 638 plants collected from various regions of Korea from 1994 to 1996, 67 were pre-screened in fields naturally infested with P. drechsleri, which is the causal pathogen of rhizome rot of Atractylis. Among the pre-screened sources, 18 (ca. 26.8%) were highly resistant to the pathogen in leaf inoculation. In the root inoculation test, abundant sporangia were formed in susceptible plant roots, while only a few or no sporangia were produced on the roots which were found resistant in the leaf inoculation test. Among the selected resistant plants, A. japonica 96066 and 96104 were used to cross with another species, A. macrocephala 96362 that showed high yield with good quality of rhizome but susceptible to the pathogen. The F$_1$hybrids designated as HA03 turned out to be resistant to the pathogen, indicating that resistant gene(s) was inherited. Among intra-species hybrids of A. japonica, HA07 and HA09 were resistant to the pathogen in leaf inoculation and moderate in root inoculation. However, HA08 was susceptible in both inoculation tests. This result suggests that the parent material might be genetically heterogeneous. Further genetic study should be carried out to verify this phenomenon.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.63-67
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• 2002

To understand plant-pathogen interactions, a complete set of hot pepper genes differentially expressed against pathogen attack was isolated. As an initial step, hundreds of differentially expressed cDNAS were isolated from hot pepper leaves showing non-host resistance against bacterial plant pathogens (Xanthomonas campestris pv. glycines and Pseudomonas syringae pv. syringae) using differential display reverse transcription polymerase chain reaction (DDDRT-PCR) technique. Reverse Northern and Northern blot analyses revealed that 50% of those genes were differentially expressed in pepper loaves during non-host resistance response. Among them, independent genes without redundancy were micro-arrayed for further analysis. Random EST sequence database were also generated from various CDNA libraries including pepper tissue specific libraries and leaves showing non-host hypersensitive response against X. campestris pv. glycines. As a primary stage, thousands of cDNA clones were sequenced and EST data were analyzed. These clones are being spotted on glass slide to study the expression profiling. Results of this study may further broaden knowledge on plant-pathogen interactions.

• The Plant Pathology Journal
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• v.25 no.2
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• pp.113-120
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• 2009

Microscopic study of chili pepper (Capsicum annuum L.) infected with Phytophthora capsici, causing Phytophthora blight of chili pepper, was conducted to compare histological and cytological characteristics in the root and stem of susceptible (C. annuum cv. Bugang) and resistant (C. annuum cv. CM334) pepper cultivars. The susceptible pepper roots and stems were extensively penetrated and invaded by the pathogen initially into epidermal cells and later cortical and vascular cells. Host cell walls adjacent to and invaded by the infecting hyphae were partially dissolved and structurally loosened with fine fibrillar materials probably by cell wall-degrading enzymes of the pathogen. In the resistant pepper, the pathogen remained on root epidermal surface at one day after inoculation, embedded and captured in root exudation materials composed of proteins and polysaccharides. Also the pathogen appeared to be blocked in its progression at the early infection stages by thickened middle lamellae. At 3 days after inoculation, the oomycete hyphae were still confined to epidermal cells of the root and at most outer peripheral cortical cells of the stem, resulting from their invasion blocked by wound periderms formed underneath the infection sites and/or cell wall appositions bounding the hyphal protrusions. All of these aspects suggest that limitation of disease development in the resistant pepper may be due to the inhibition of the pathogen penetration, infection, invasion, and colonization by the defense structures such as root exudation materials, thickened middle lamellae, wound peridems and cell wall appositions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.97-107
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• 1990

The epidemiology of plant disease deals with the dynamic processes of host-pathogen interactions, which determine the prevalence and severity of the disease. Epidemic processes for most foliar diseases of plants follow a series of steps: arrival of pathogens on plant surfaces, initial infection, incubation period, latent period, sporulation, dissemination of secondary inoculum, and infectious period. These complex biological processes are influenced by the environment-Man also often interfers with these processes by altering the host and pathogen populations and the environment. Slowing or halting any of the epidemic processes can delay the development of the epidemic, so that serious losses in yield due to disease do not occur. It is generally recognized that the most effective and efficient method of minimizing disease damage is through the use of resistant cultivars, particularly when other methods such as fungicide applications are not economically feasible-Populations of plant pathogens are not genetically uniform nor are they necessarily stable. Cultivars bred for resistance to current populations of a pathogen may not be resistant in the future due to selection pressures placed on the pathogen populations. Understanding population development and genetic variability in the pathogen, and knowledge of the genetics of resistance in the plant should help in developing breeding strategies that wi1l provide effective and stable disease control through genetic resistance. In the United States, soybeans have ranked first in value of crops sold off the farm in recent years. Soybeans have been the leading U. S.

• Korean Journal of Medicinal Crop Science
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• v.21 no.1
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• pp.27-31
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• 2013

This study was conducted to isolate and identify the fungal pathogen causing seedling rot of Lithospermum erythrorhizon Siebold & Zuccarini, and to know the optimum growing temperature for decreasing seedling rot of Lithospermum erythrorhizon. On the basis of morphological characteristics, EF-1a sequence analysis, and pathogenecity to host plant, the fungi isolated from seedling rot and seeds of Lithospermum erythrorhizon were identified as Fusarium fujikuroi, indicating that disease causing fungus is seed-borne pathogen. Optimum temperature for germination of seeds of Lithospermum erythrorhizon was $15{\sim}20^{\circ}C$, but pathogenicity of Fusarium fujikuroi was shown more readily at $25{\sim}30^{\circ}C$. These results suggested that seedling culture of Lithospermum erythrorhizon between $15^{\circ}C$ and $20^{\circ}C$ might reduce seedling rot of Lithospermum erythrorhizon caused by seed-borne pathogen Fusarium fujikuroi.

• Genomics & Informatics
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• v.9 no.4
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• pp.197-199
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• 2011

The biological interpretation of two-dimensional (2D) gel electrophoresis experiments is a key step toward understanding the functions of biological systems. We here present a web-based integrated database, called 2DSpotDB, for the management of proteome data derived from several pathogens. The 2DSpotDB was established as a part of the management of a pathogen proteome project at the Korea National Institute of Health. The goals of the 2DSpotDB implementation are to store and define important pathogen genes, retrieve information obtained by 2D polyacrylamide gel electrophoresis and mass spectrometry, and create an integrated system to provide pathogen proteome information for biological scientists. This database currently contains 14 gels and information on 387 protein spots, among which 329 proteins were identified and annotated.

• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.289-295
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• 2019

Acute diarrhea is a global health problem that causes high morbidity and mortality in children. Notably, enteric pathogen co-infections have been suggested to play an important role in gastroenteritis. In this study, we analyzed 1150 stool specimens of patients who visited the pediatric ward of Dongguk University Hospital in Gyeongju province from January 2011 to December 2017. The average isolation rate of potential stool pathogens over 7 years was 37.3% (429/1150), and coinfections were observed in 51 patients (51/429; 11.9%). In the 51 co-infection cases, the most frequent type of co-infection was found to be that of virus-bacteria (33/51). The most frequently detected bacterial pathogen among the co-infected cases was Clostridium spp. (22/51), out of which Clostridium perfringens was found to be the main pathogen (16/22; 72.7%). Escherichia coli spp. were the second most common bacterial pathogens found in 12 cases (12/51; 23.5%), with 10 cases of E. coli EPEC. Furthermore, the most frequently implicated viral pathogen among the co-infected cases was norovirus (16/51), followed by rotavirus (12/51).