• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.73-74
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• 2005

• Mycobiology
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• v.49 no.1
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• pp.89-94
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• 2021

Forty-three (n = 43) endophytic fungi with different morphologic characteristics were from a medicinal plant Sceletium tortuosum, were utilized to investigate their antifungal effectiveness against pathogenic fungi. All fungal isolates exhibited antifungal activity against one or more pathogens in the dual culture test whereas only 33 fungal culture filtrates (77%) showed decent antifungal effect. Fusaria and Aspergillus were the dominate genus that displayed significant antifungal activity. Isolates GG02, GG09, ND15, and ND17 showed the broadest spectrum of antifungal activity. Furthermore, culture filtrate of Fusarium sp. DR08 exhibited a broad range of antifungal activity against all the pathogens. The results suggest endophytic fungi isolated from medicinal plant might be a source of novel bioactive molecules. To the best our knowledge, this is the first report on endophytic fungi isolated from native kougoed exhibiting antifungal activity against plant fungal pathogens.

• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1027-1036
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• 2020

Stipa purpurea is a unique and dominant herbaceous plant species in the alpine steppe and meadows on the Qinghai-Tibet Plateau (QTP). In this work, we analyzed the composition and diversity of the culturable endophytic fungi in S. purpurea according to morphological and molecular identification. Then, we investigated the bioactivities of these fungi against plant pathogenic fungi and 1-aminocyclopropane-1-carboxylate deaminase (ACCD) deaminase activities. A total of 323 fungal isolates were first isolated from S. purpurea, and 33 fungal taxa were identified by internal transcribed spacer primers and grouped into Ascomycota. The diversity of endophytic fungi in S. purpurea was significantly higher in roots as compared to leaves. In addition, more than 40% of the endophytic fungi carried the gene encoding for the ACCD gene. The antibiosis assay demonstrated that 29, 35, 28, 37 and 34 isolates (43.9, 53.1, 42.4, 56.1, and 51.5%) were antagonistic to five plant pathogenic fungi, respectively. Our study provided the first assessment of the diversity of culture-depending endophytic fungi of S. purpurea, demonstrated the potential application of ACCD activity and antifungal activities with potential benefits to the host plant, and contributed to high biomass production and adaptation of S. purpurea to an adverse environment.

• Mycobiology
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• v.40 no.1
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• pp.59-65
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• 2012

Antagonistic microorganisms against $Rhizoctonia$ $solani$ were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by $R.$ $solani$ AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as $Bacillus$ $subtilis$ subsp. $subtilis$. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance ($^1H$ NMR), carbon nuclear magneric resonance ($^{13}C$ NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.339-345
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• 2002

Antifungal substances were isolated from solid cultures of Fusarium equiseti FO-68 obtained from arrowhead and Fusarium sp. FO-510 obtained from egg plant, and then their antifungal activities were investigated against plant pathogenic fungi in vitro and in vivo. An antifungal substance was purifed from rice solid cultures of F. equiseti FO-68 and identified as equisetin. In addition, two antibiotic substances were isolated from solid cultures of Fusarium sp. FO-510 and their chemical structures were determined to be zearalenone and 8'-hydroxyzearalenone. in vitro, equisetin and zearalenone inhibited mycelial growth of most of the plant pathogenic fungi tested, whereas 8'-hydroxyzearalenone hardly inhibited fungal growth. In vitro, equisetin effectively controlled the development of tomato gray mold and tomato late blight. Zearalenone exhibited in vivo antifungal activity against rice blast, rice sheath blight, tomato gray mold, and tomato late blight. However, 8'-hydroxyzearale-none did not control the development of plant diseases except tomato gray mold. This is the first report on the antifungal activities of equisetin, zearalenone, and 8'-hydroxyzearalenone.

• 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.43 no.4
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• pp.435-443
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• 2015

Sixty-one endophytic fungus strains with different colony morphologies were isolated from the leaves, stems and roots of Tephrosia purpurea with colonization rates of 66.95%, 37.50%, and 26.92%, respectively. Based on internal transcribed spacer sequence analysis, 61 isolates were classified into 16 genera belonging to 3 classes under the phylum Ascomycota. Of the 61 isolates, 6 (9.84%) exhibited antifungal activity against one or more indicator plant pathogenic fungi according to the dual culture test. Isolate TPL25 had the broadest antifungal spectrum of activity, and isolate TPL35 was active against 5 plant pathogenic fungi. Furthermore, culture filtrates of TPL25 and TPL35 exhibited greater than 80% growth inhibition against Sclerotinia sclerotiorum. We conclude that the endophytic fungal strains TPL25 and TPL35 are promising sources of bioactive compounds.

• Mycobiology
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• v.35 no.4
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• pp.210-214
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• 2007

Antibacterial and antifungal activities of liquid culture filtrate, water and ethanol extract (solid culture) of Stereum ostrea were evaluated against 5 bacteria and 3 plant pathogenic fungi. To determine the minimal inhibitory concentration (MIC), we studied $5{\sim}300\;mg/ml$ concentrations against bacteria and fungi separately. The MIC was 10 mg/ml for Bacillus subtilis and 40 mg/ml for Colletotrichum gloeosporioides and Colletotrichum miyabeanus. Liquid culture filtrate was more effective against Gram positive than Gram negative bacteria, and Staphylococcus aureus was the most inhibited (20.3 mm) bacterium. Water and ethanol extracts were effective against both Gram positive and Gram negative bacteria, and water extract was better than ethanol extract. In water and ethanol extract, inhibition zones were 23.6 and 21.0 mm (S. aureus) and 26.3 and 22.3 mm (Pseudomonas aeruginosa), respectively. For plant pathogenic fungi, the highest and lowest percent inhibition of mycelial growth (PIMG) was found 82.8 and 14.4 against C. miyabeanus and Botrytis cinerea in liquid culture filtrate, respectively. In water extract, the PIMG was found to be the highest 85.2 and lowest 41.7 for C. miyabeanus and C. gloeosporioides, respectively. The inhibitory effect of ethanol extract was better against C. miyabeanus than C. gloeosporioides and B. cinerea. Among 3 samples, water extract was the best against tested pathogenic fungi. This study offers that the extracts isolated from S. ostrea contain potential compounds which inhibit the growth of both bacteria and fungi.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1337-1345
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• 2014

A novel antifungal protein produced by the fungal strain Penicillium citrinum W1, which was isolated from a Southwest Indian Ocean sediment sample, was purified and characterized. The culture supernatant of P. citrinum W1 inhibited the mycelial growth of some plant pathogenic fungi. After saturation of P. citrinum W1 culture supernatants with ammonium sulfate and ion-exchange chromatography, an antifungal protein (PcPAF) was purified. The N-terminal amino acid sequence analysis showed that PcPAF might be an unknown antifungal protein. PcPAF displayed antifungal activity against Trichoderma viride, Fusarium oxysporum, Paecilomyces variotii, and Alternaria longipes at minimum inhibitory concentrations of 1.52, 6.08, 3.04, and $6.08{\mu}g/disc$, respectively. PcPAF possessed high thermostability and had a certain extent of protease and metal ion resistance. The results suggested that PcPAF may represent a novel antifungal protein with potential application in controlling plant pathogenic fungal infection.