• Mycobiology
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• v.43 no.3
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• pp.333-338
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• 2015

In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria.

• Research in Plant Disease
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• v.26 no.1
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• pp.1-7
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• 2020

The succinate dehydrogenase inhibitor (SDHI) is a class of fungicides, which is widely and rapidly used to manage fungal pathogens in the agriculture field. Currently, fungicide resistance to SDHIs has been developed in many different plant pathogenic fungi, causing diseases on crops, fruits, vegetables, and turf. Understanding the molecular mechanisms of fungicide resistance is important for effective prevention and resistance management strategies. Two different mechanisms have currently been known in SDHI resistance. The SDHI target genes, SdhB, SdhC, and SdhD, mutation(s) confer resistance to SDHIs. In addition, overexpression of ABC transporters is involved in reduced sensitivity to SDHI fungicides. In this review, the current status of SDHI resistance mechanisms in phytopathogenic fungi is discussed.

• Mycobiology
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• v.29 no.3
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• pp.142-144
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• 2001

The tetrahydropahnatine alkaloid was assayed against spore germination of some saprophytic and pathogenic fungi e.g., Alternaria solani, A. brassicicola, A. brassicae, A. alternata, Erysiphe pisi, Curvularia lunata, C. pallescens, C. maculans, Curvularia species, Colletotrichum species, C. musae, Helminthosporium echinoclova, H. pennisetti, H. spiciferum, and Heterosporium sp. It inhibite spore germination of all the fungi tested. Colletotrichum spp. Curvularia lunata, Helminthosporium spiciferum and Heterosporium sp. were most sensitive as complete inhibition of spore germination was observed at very low concentration(200 ppm).

• Mycobiology
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• v.33 no.4
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• pp.206-209
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• 2005

Narceine methyl ester and narceine are potent alkaloids which were isolated from Corydalis longipes were found effective in vitro at very low concentration, i.e., $100{\sim}500\;ppm$ against spore germination of some test plant pathogenic fungi (Alternaria solani, A. tagetica, Cercospora abelmoschi, Curvularia maculans, Erysiphe cichoracearum, E. pisi, Fusarium udum, Helminthosporium oryzae, H. penniseti, Ustilago cynodontis). Among the test, phytopathogens the spores of F. udum, C. maculans and H. penniseti were highly sensitive at 200 ppm. However, spores of E. pisi, A. solani and A. tagetica were less sensitive at low concentration followed by other test fungi. Most of the fungi showed zero or nearly zero percent spore germination at 400 and 500 ppm.

• The Plant Pathology Journal
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• v.15 no.5
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• pp.280-286
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• 1999

Lichen-forming (LFF) or lichenicolous fungi (LCF) were isolated from the lichens collected at‘Backwoon’mountain area,‘Chiri’mountain area and‘Sorok’island in the southern regions of Korea and were screened for antagonistic efficacy against several phyto-pathogenic fungi. Symbiotic algae-free LFF and LCF were isolated by the following methods: I) discharged spores (ascospores), II) macerated thallus suspension and III) direct use of thallus fragments. Among 58 isolates obtained from 34 lichens, 8 isolates showed antifungal activity against Rhizoctonia solani. Antifungal activities of the strongest antagonistic isolate (LB9810) originated from the thallus of Parmelia quercina lichen were evaluated against 15 phyto-pathogenic fungi. When crude methanol extract of mycelia of the LB8910 isolate was employed at the rate of 0.5% (v/w), fungal growth of Magnaporthe grisea and Rhizoctonia solani was severly and Rhizoctonia solani was severly inhibited as much as approximately 60% compared to control. Growth of various food-borne same extract. The extract was successively partitioned with n-hexane, ethyl acetate and n-butanol. n-Hexane fraction displayed the strongest antifungal activities against R. solani. The LB9810 isolate was finally identified as Fusarium equiseti (Corda) Sacc., which has not been reported as LFF or LCF yet. Therefore, it is very likely that F. equiseti isolated it the study was originated from the contaminants associated with thallus fragments rather than from LFF or LCF.

• Mycobiology
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• v.41 no.4
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• pp.234-242
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• 2013

A total of 62 bacterial isolates were obtained from Gomsohang mud flat, Mohang mud flat, and Jeju Island, Republic of Korea. Among them, the isolate CNU114001 showed significant antagonistic activity against pathogenic fungi by dual culture method. The isolate CNU114001 was identified as Bacillus amyloliquefaciens by morphological observation and molecular data analysis, including 16SrDNA and gyraseA (gyrA) gene sequences. Antifungal substances of the isolate were extracted and purified by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. The heat and UV ray stable compound was identified as iturin, a lipopeptide (LP). The isolate CNU114001 showed broad spectrum activity against 12 phytopathogenic fungi by dual culture method. The semi purified compound significantly inhibits the mycelial growth of pathogenic fungi (Alternaria panax, Botrytis cinera, Colletotrichum orbiculare, Penicillium digitatum, Pyricularia grisea and Sclerotinia sclerotiorum) at 200 ppm concentration. Spore germ tube elongation of Botrytis cinerea was inhibited by culture filtrate of the isolate. Crude antifungal substance showed antagonistic activity against cucumber scleotiorum rot in laboratory, and showed antagonistic activity against tomato gray mold, cucumber, and pumpkin powdery mildew in greenhouse condition.

• Mycobiology
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• v.31 no.3
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• pp.151-156
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• 2003

Two fungal isolates obtained from roots of Cymbidium goeriingii in Jeju island were confirmed to be symbiotic with orchid plantlets, and were compared with other orchid mycorrhizal(OM) fungi previously isolated. The two isolates differed in their peloton structures formed in the roots of Cymbidium kanran hybrid 'Chungsu' and in responses of orchid plant. These two isolates differed from the additionally tested OM fungi in some features, and from root damaging species of Rhizoctonia and Fusarium as based on cluster analysis after PCR-RAPD with the primers, Bioneer-28 and OPO-2. With this simple and fast technique, it was possible to distinguish OM fungi from the plant root pathogenic fungi based on calculation of their polymorphic bands. This technique can therefore be helpful to distinguish the OM fungi from the root pathogens. Particularly, the new isolates are considered as new resource of symbiotic fungi for horticultural industries.

• The Plant Pathology Journal
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• v.23 no.2
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• pp.97-102
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• 2007

A total of 39 essential oils were tested for antifungal activities as volatile compounds against five phytopathogenic fungi at a dose of 1 ${\mu}l$ per plate. Five essential oils showed inhibitory activities against mycelial growth of at least one phytopathogenic fungus. Origanum vulgare essential oil inhibited mycelial growth of all of the five fungi tested. Both Cuminum cyminum and Eucalyptus citriodora oils displayed in vitro antifungal activities against four phytopathogenic fungi except for Colletotrichum gloeosporioides. The essential oil of Thymus vulgaris suppressed the mycelial growth of C. gloeosporioides, Fusarium oxysporum and Rhizoctonia solani and that of Cymbopogon citratus was active to only F. oxysporum. The chemical compositions of the five active essential oils were determined by gas chromatography-mass spectrometry. This study suggests that both E. citriodora and C. cyminum oils have a potential as antifungal preservatives for the control of storage diseases of various crops.

• Mycobiology
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• v.30 no.1
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• pp.55-56
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• 2002

The 4',7-dimethoxyisoflavone was isolated from the leaves of Albizzia lebbeck for the first time. This flavonoid showed antifungal activity against some plant pathogenic fungi tested in vitro, e.g., Alternaria melongenae, A. brassicicola, A. brassicae, Curvularia maculans, C. pallescens, C. lunata, Curvularia species, Colletotrichum species, Helminthosporium penniseti and H. speciferum. The sensitivity of different fungi to this chemical varied considerably. A. brassicae was most sensitive as complete inhibition of germination was observed in all the concentrations(100 to 1000 ppm) of the chemical. Similar effect on H. speciferum and Curvularia species was also recorded at 500 ppm, whereas H. penniseti did not germinate at 250 ppm. A. melongenae and A. brassicicola also did not germinate at 1000 ppm while 750 ppm was inhibitory to C. lunata and C. maculans. Germination in almost all fungi was significantly inhibited at each concentration in comparison to control except Curvularia sp. and H. speciferum. Use of 4',7-dimethoxyisoflavone to control some plant diseases under field conditions has been suggested.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.705-711
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• 2019

Understanding the microbial community and function are crucial knowledge for crop management. In this study, bacterial and fungal community structures both rhizosphere and endosphere in kiwifruit were analyzed to gain our knowledge in kiwifruit microbiome. Microbial community in rhizosphere was less variation than endosphere community. Functional prediction results demonstrated that abundance of saprotrophic fungi was similar in both rhizosphere and endosphere, but potential pathogenic fungi was more abundance in endosphere than in rhizosphere. This finding suggested that maintain healthy soil is the first priority to protect the host plant against biotic stresses.