• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.23-23
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• 2003

Chestnut blight, caused by Cryphonectria parasitica, is the most destructive disease of American and European chestnut trees. A total of 672 C prasitica was isolated from blight lesion on chestnut twigs, which were collected from major chestnut plantations all over Korea in 1999. Isolation rates were over 30% in Kyunggj-, Kyongnam-, and Chonnam-do. The highest isolation rate was 37.4% and recorded in Kyongnam-do. On the other hand, Chonbuk-do had the lowest isolation rate as 13.5%. In grouping of C parasitica by colony shape and color, yellow colony with irregular margin were the most dominant colony type with a frequency of 65.2%. When the 672 isolates were inoculated on the chestnut twigs, 380 isolates (56.5%) caused lesions larger than the standard virulent isolate EP155-2, while 158 isolates (23.4%) caused smaller lesions than the standard hypovirulent isolate UEP-1. In Bavendamm test that determines phenol oxidase activity, 97.1% of all the isolates resulted the same or darker discoloration than EP155-2, and only 12.2% resulted the same or lighter discoloration than UEP-1. In the vegetative compatibility (VC) tests, total 670 isolates were divided into 121 VC groups (VCGs). Kyongnam-, Chonnam-, and Chungnam-do, the three principal chestnut plantation area, had 49, 33, and 27 VCGs, respectively. Among the VCGs, the biggest VCG, KR-VC104, was composed of 164 isolates and the second biggest VCG had 62 isolates. But, 64 of 121 VCGs consisted of sole member. More than 65.8% of KR-VC104, was isolated from the three provinces, Kyongnam-, Kangwon-, and Chungbuk-do. In KR-VC104, 62.8%, 59.1%, and 85.9% of the isolates looked like virulent in colony type, pathogenicity test, and Bavendamm test. In ds-RNA detection tests using cellulose chromatography, 77 of total 650 isolates were ds-RNA positive and detected ds-RNA segments were approximately 12kb, 3kb, 2.7kb, 2kb, and 1.8kb in size. Among the 77 isolates, 46 isolates had 12kb and 25 isolates had 12kb and 2.7kb. Other 6 Isolates had small ds-RNA segments. Kyongnam-, Chonnam-, and Chungnam-do had 43, 16, and 5 ds-RNA positive isolates, respectively. Among the 121 VCGs, only 29 VCGs had ds-RNA positive isolates.(중략)

• Korean Journal Plant Pathology
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• v.14 no.4
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• pp.345-349
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• 1998

Fifty isolates of myxobacteria were isolated from soils from several areas in Korea during 1996-1997 and bioactivity against plant pathogenic fungi of these isolates was examined. A myxobacterial isolate KR025 showed good antifungal activities against Pyricularia oryzae, Cryphonectria parasitica, Colletotrichum lagenarium, and C. gloeosporioides but did not against Rhizoctonia solani, Fusarium oxysporum and Pythium ultimum. The bacterium was identified as Myxococcus fulvus based on morphological and physiological characteristics. Antifungal substances were extracted from culture broth and bacterial cell of Myxococcus fulvus KR025 by ethyl acetate. Antifungal substance of Myxothiazole (100 ${\mu}{\textrm}{m}$/ml) produced by Myxococcus fulvus KR 025 controlled 97.0% rice blast, tomato late blight, wheat leaf rust, and barley powdery mildew and showed 45.0 and 82.6% disease control of rice sheath blight and cucumber gray model, respectively.

• Journal of the Korean Wood Science and Technology
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• v.31 no.1
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• pp.1-9
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• 2003

Antimicrobial activities of plant extractives were investigated to develop a natural fungicide. Two stilbenoids and five flavonoids were isolated from wood extractives of Hovenia dulcis (Rhamnaceae) which had been selected due to its high antifungal activity among the tested species. The chemical structures of isolated compounds were determinded as : 5-hydroxy-7-methoxyflavone, 5,7-dihydroxyflavone (chrysin), 5,7-dihydroxyflavanone (pinocembrin), 3,5,7-trihydroxyflavanone (pinobanksin), 3,4',5,7-tetrahydroxyflavanone (aromadendrin), 3-hydroxy-5-methoxystilbene and 3,5-dihydroxystilbene (pinosylvin) on the basis of Mass and NMR spectroscopic data. According to the results of antifungal test, 3-hydroxy-5-methoxystilbene was evaluated as the strongest antifungal compound among the tested compounds and next were pinocembrin and pinosylvin, but those also had high hyphal growth inhibition activities against C. parasitica, T. versicolor, T. palustris and T. viride. However, pinobanksin, 5-hydroxy-7-methoxyflavone, chrysin and aromadendrin showed very low antifungal activity. In this regard, it could inferred that high antifungal activity of wood extractives of H. dulcis were derived from 3-hydroxy-5-methoxystilbene, pinocembrin and pinosylvin, respectively.

• Journal of Mushroom
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• v.8 no.2
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• pp.41-50
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• 2010

Mycoviruses have been found in many fungal species including mushrooms. Double-stranded (ds) RNA genomes were common type in mycoviruses, but single-stranded (ss) RNA mycoviruses were also reported in some fungal species. Sequencing analysis using cDNA cloning experiments revealed that mycoviruses can be classified into several different virus families such as Totiviridae, Hypoviridae, Partitiviridae and Barnaviridae etc. Because the nucleotide sequence data that are available in these days are very limited in a number of mycoviruses, the existence of more diverse viral groups in fungi are currently expected. In this review, we selected four different fungal groups, which were considered as the model systems for mycovirus related studies in both plant pathogenic fungi and edible mushroom species, and discussed about their molecular characteristics of diverse mycoviruses. The plant pathogenic fungi introduced here were Cryphonectria parasitica and Helminthosporium victoriae and the edible mushroom species were Agaricus bisporus and Pleurotus ostreatus.

• Mycobiology
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• v.46 no.4
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• pp.429-439
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• 2018

To develop a convenient promoter analysis system for fungi, a null-pigment mutant (NPG) of Aspergillus nidulans was used with the 4'-phosphopantetheinyl transferase (PPTase) gene, npgA, which restores the normal pigmentation in A. nidulans, as a new reporter gene. The functional organization of serially deleted promoter regions of the A. nidulans trpC gene and the Cryphonectria parasitica crp gene in filamentous fungi was representatively investigated to establish a novel fungal promoter assay system that depends on color complementation of the NPG mutant with the PPTase npgA gene. Several promoter regions of the trpC and crp genes were fused to the npgA gene containing the 1,034-bp open reading frame and the 966-bp 3' downstream region from the TAA, and the constructed fusions were introduced into the NPG mutant in A. nidulans to evaluate color recovery due to the transcriptional activity of the sequence elements. Serial deletion of the trpC and crp promoter regions in this PPTase reporter assay system reaffirmed results in previous reports by using the fungal transformation step without a laborious verification process. This approach suggests a more rapid and convenient system than conventional analyses for fungal gene expression studies.