• The Plant Pathology Journal
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• v.17 no.6
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• pp.364.3-364
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• 2001

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.92.2-93
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• 2005

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.29-29
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• 2015

Clubroot disease is caused by the soil-born obligate plant pathogen Plasmodiophora brassicae. This pathogen can infect all cruciferous vegetables and oil crops, including Brassica rapa, B. oleracea, B. napus, and other Brassica species. Clubroot disease is now considered to be a major problem in Chinese cabbage production in China, Korea, and Japan. We collected several hundreds of P. brassicae infected galls from Korea, and isolated the single spore from the collection. For establishment of novel isolation, and mass-propagation methods for singe spore isolates of P. brassicae pathogen, we developed new filtration method using both cellulose nitrate filter and syringe filter. Accurate detection of P. brassicae pathogen in the field was done by using real-time PCR in the potential infested soil. When we tested the different pathogenicity on commercial Chinese cabbage varieties, P. brassicae from collected galls showed various morphological patterns about clubroot symptom on roots. To date, 8 CR loci have been identified in the B. rapa genome using the quantitative trait loci (QTL) mapping approach, with different resistant sources and isolates. We are trying to develop the molecular marker systems for detect all 8 CR resistant genes. Especially for the study on the interaction between pathogens and CR loci which are not well understood until now, genome wide association studies are doing using the sequenced inbred lines of Chinese cabbage to detect the novel CR genes.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.69-76
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• 2004

Asian Dust samples were collected in the ambient air of Seosan, Western Korea, in spring of 2000∼2002. PM (Particulate Matter) concentrations were 199,8$\mu\textrm{g}$/㎥ in the first Asian Dust period (March, 23∼24) and 249.4$\mu\textrm{g}$/㎥ in the second period (April, 7∼9) of 2000. Compared with the concentrations in 2000, relatively low PM concentrations, 157.3$\mu\textrm{g}$/㎥ were measured in the periods of 2001 (April, 24∼26). Especially high PM concentration 953.1$\mu\textrm{g}$/㎥ were measured in the periods of 2002 (March, 21∼22). The variation in the PM concentration was observed according to the time for the formation of Asian dust. Considering the particle size distributions of Asian dust, a high concentration was also observed in coarse particle region. The results of backward trajectory model showed the route of the dust storms from northern area of Mongol and Gobi desert. Various mycelia grown from fungal spores were observed on the PM samples and identified at the genus level. All the genera from the three years (2000∼2002), Fusarium, Aspergillus, Penicillium, Basipetospora, Epicoccum and Monotospora are hyphomycetes in the division Fungi imperfecti (Deuteromycota). Fungal composition on the dust sample in March, 2000 was similar to the result of March, 2002. However, the result of April, 2001 was obviously different from the other dust periods. The variations of fungal compositions between the dust periods could be caused by the trajectories of the dust storms.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.112.1-112
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• 2003

Genetic diversity of Plasmodiophora brassicae from major chinese cabbage cultivating areas in Korea was analyzed by using PCR-RFLP and RAPD. Single spores of P brassicae isolated from galls of club root made induce lesion on chinese cabbage successfully. The PCR-RFLP and RAPD by primers PbITS, URP 3, 6 and OPA 7 revealed that single spore isolates showed various DNA polymorphisms among them unrelated geographic origins. These results indicate that P. brassicae population in Korea showed genetic difference among them. This study could be facilitate to identify genetic characteristics ofP. brassicae based on DNA polymorphisms between single spore isolates and to get basic information which can be used to advanced resistance breeding against club root of chinese cabbage.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.245-251
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• 1995

Nine hundred and ninety-two isolates of Botrytis cinerea were obtained from infected strawberries, tomatoes and cucumbers in Taejon, Gongju, Puyo, Nonsan and Kimhae in Korea. Six hundred forty-two (64.7%) isolates were benomyl resistant (BR), 245 (24.7%) were procymidone resistant (PR), and 105 (10.6%) were dichlofluanid resistant (DR). In the minimum inhibitory concentration (MIC) test, DR isolates showed mycelial growth on the PDA incorporated with 100 or 500 $\mu\textrm{g}$/ml of dichlofluanid, while dichlofluanid sensitive (DS) isolates did not grow on the PDA incorporated even with 10 $\mu\textrm{g}$/ml of dichlofluanid. Chemical concentrations for inhibition of spore germination were much lower than those for inhibition of mycelial growth. IC50 values, the effective concentrations for 50% inhibition of spore germination, for DR were 0.11~0.29 $\mu\textrm{g}$/ml, whereas they were 0.04~0.09 $\mu\textrm{g}$/ml for DS isolates. In comparison of fitness-related characteristics such as virulence, sclerotial formation, and sporulation, DR isolates were inferior to DS isolates. However, mycelial growth was little different between DR isolates and DS isolates.

• Journal of fish pathology
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• v.23 no.1
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• pp.113-118
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• 2010

The present work describes myxozoan parasite found in the skin of cultured snakehead, Channa argus fingerings (total length, 5.5~7.2 cm) from Busan, Korea. Nature spores and plasmodia were found in the skin mucus of infected fishes. In fresh state, the total length of the spore was $27.96{\pm}2.50{\mu}m$. The size of spore body was $14.16{\pm}1.78{\mu}m{\times}4.88{\pm}0.61{\mu}m$. The polar capsules were pyriform and the size was $5.57{\pm}0.66{\mu}m{\times}1.36{\pm}0.33{\mu}m$. This is the first report of Henneguya sp. from cultured fish species in Korea, and further studies are necessary for definitive identification.

• Parasites, Hosts and Diseases
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• v.32 no.1
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• pp.57-60
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• 1994

In order to search the fate of Thelohonellus kitauei spores the extrusion rates of the polar filaments were monitored in uipo chronologically. Preserved spores suspended with various solutions at $-70^{\circ}C$ showed almost the same vigorous pattern as early freezing stages up to 1,750 days after initial preservation. It revealed that the vlabllltles of some spores suspended with 0.45% and 0.9% NaCl solutions and distilled water at $5^{\circ}C$ continued for 1,628 days, 1,614 days and 1,721 days, respectively. And, the life spans of some spores in the previous solutions added with antibiotics at $5^{\circ}C$ were 1,628 days, 1,614 days and 1,714 days, respectively. Key words: TheLohanellus kitnuei, spore, extrusion rate of polar filament, life span

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.83-86
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• 2001

Effects of photoperiods, 24L or 24D, on the growth of the silkworm-dongchunghacho, the silkworm vegetable wasp and plant worm, were investigated. Exposure of the fungi under the photoperiod of 24L for at least 3 days during the cultivation of the fungi after the completion of endosclerotium in the host accelerated the spore formations but the growth of the fruiting bodies was inhibited. On the contrary, the photoperiod of 24D inhibited the spore formation, but accelerated the growth of fruiting bodies without spores. Accordingly, to produce silkworm vegetable wasp and plant worm of large-size fruiting bodies with over 3 cm in length, it is indicated that recommendable light condition is a photoperiod of 24D during the cultivation until the length of the fruiting body arrives at over 3 cm.

• Mycobiology
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• v.28 no.4
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• pp.185-189
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• 2000

The antifungal activity of methanolic extracts of Centella asiatica and Andrographis paniculata leaves was observed against fourteen fungi, viz., Alternaria alternata, A. brassicae, A. brassicicola, A. solani, A. tenuissima, Cercospora blumae, Curvularia lunata, C. penniseti, and Drechslera monoceras, D. oryzae, D. turitica, Fusarium albizziae and F. udum. Different concentrations of the methanolic extract (1000, 2000, 3000, 5000, 7000, 10000ppm) were used. The effect of mixed leaf extract (1500 ppm of C. asiatica + 1500 ppm of A. paniculata) and its 1:2 ad 1:4 dilutions were also studied. The individual extracts of both the plants showed significant inhibitory effect on spore germination of all the fungi tested. F. udum, F. albizzae, D. oryzae, D. turtica, and D. monoceras were particularly sensitive to these extracts. In general, the extract of C. asiatica showed a higher inhibitory effect in all concentrations against all the fungi as compared to A. paniculata, except for A. brassicae A. solani, D. oryzae, D. penniseti and Curvularia sp. The inhibitory effect of extracts increased when they were used in combination with or without dilutions against A. brassicicola, A. solani A. brassicae, A. alternata, A. tenussima, C. blumae, C. lunata, C. penniseti and Curvularia species. Higher efficacy of active ingredient of these extracts under field condition is envisaged against plant pathogens.