• Mycobiology
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• v.45 no.4
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• pp.385-391
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• 2017

The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, ${\beta}$-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, ${\beta}$-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, ${\beta}$-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.

• KSBB Journal
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• v.23 no.3
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• pp.219-225
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• 2008

For the production of an antifungal compound, one strain (I-8) was selected from approximately 400 strains isolated from various soil samples. The optimum carbon source, nitrogen source and pH culture conditions for the production of the antifungal compound were investigated. ISP No. 2 medium (yeast extract 0.4%, malt extract 1% and dextrose 0.4%, at pH 8) was determined to be the optimum medium. Strain I-8 showed broad antifungal activity against the plant pathogenic fungi tested, including Sclerotinia sclerotiorum KACC 41065, as well as cellulase and chitinase activities in an agar plate assay. The extraction of antifungal compounds was performed using ethyl ether and ethyl acetate. In a culture broth of strain I-8, the ethyl acetate extract exhibited effective growth inhibition against 14 of the 20 phytopathogenic fungi tested. By mixing the ethyl acetate extract from I-8 with the ethyl ether extract from the fungus 13-16, which shows specific antifungal activity against Colletotrichum orbiculare KACC 40808, the antifungal activity of I-8 against phytopathogenic fungi was confirmed to be slightly increased. Strain I-8 showed strong growth inhibition against 16 phytopathogenic strains in agar plate tests.

• 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.

• The Plant Pathology Journal
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• v.38 no.5
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• pp.449-460
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• 2022

This study was performed to reveal phenotypic characters and identity of symbiont bacteria of Nasutitermes as well as investigate their potential as antagonist of plant pathogenic fungi. Isolation of the symbiont bacteria was carried out from inside the heads and the bodies of soldier and worker termite which were collected from 3 locations of nests. Identification was performed using phenotypic test and sequence of 16S ribosomal DNA (16S rDNA). Antagonistic capability was investigated in the laboratory against 3 phytopathogenic fungi i.e., Phytophthora capsici, Ganoderma boninense, and Rigidoporus microporus. Totally, 39 bacterial isolates were obtained from inside the heads and the bodies of Nasutitermes. All the isolates showed capability to inhibit growth of P. capsici, however, 34 isolates showed capability to inhibit growth of G. boninense and 32 isolates showed capability to inhibit growth of R. microporus. Two bacterial strains (IK3.1P and 1B1.2P) which showed the highest percentage of inhibition were further identified based on their sequence of 16S rDNA. The result showed that 1K3.1P strain was placed in the group of type strain and reference strains of Lysinibacillus fusiformis meanwhile 1B1.2P strain was grouped within type strain and reference strains Paenibacillus alvei. The result of this study supply valuable information on the role of symbiont bacteria of Nasutitermes, which may support the development of the control method of the three above-mentioned phytopathogenic fungi.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.49-55
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• 1996

This study was conducted to find out antifungal activities of entomopathogenic fungus, Metarhizium anisopliae, against phytopathogenic fungi, Fusarium oxysporum, Botrytis cinerea and Alternaria solani. M. anisopliae was confirmed its antagonistic effect through mycelial inhibition zone of phytopathogenic fungi by culture filtrate of the antagonist. The filtrate (30%: v/v) inhibited the conidial germination of B. cinerea and F. oxysporum to 21.5% (control: 88.2%) and 53.0% (control: 78.6%), respectively and delayed the start of spore germination about 8hours. Microscopic observations proved that the addition of 10% culture filtrate of M. anisopliae restricted the growth of phytopathogenic fungus, F. oxysporum, to the formation of chlamydospore. From these results, we concluded that an addition effect of the filtrate from M. anisopliae on culturing F. oxysporum was fungistatic.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.102-108
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• 2014

The bacterial strain T-9, which shows strong antifungal activity, is isolated from the soils of Samcheok, Gangwondo and identified as Paenibacillus kribbensis according to morphological and taxonomic characteristics and 16S rRNA gene sequence analysis. The P. kribbensis strain T-9 strongly inhibits the growth of various phytopathogenic fungi including Botrytis cinerea, Colletotricum acutatum, Fusarium oxysporum f. sp. radicis-lycopersici, Magnaporthe oryzae, Phytophthora capsici, Rhizoctonia solani, and Sclerotium cepivorum in vitro. Also, the P. kribbensis strain T-9 exhibited similar or better control effects to plant diseases than in fungicide treatment through in vivo assays. In the 2-year greenhouse experiments, P. kribbensis strain T-9 was highly effective against clubroot. In the 2-year field trials, the P. kribbensis strain T-9 was less effective than the fungicide, but reduced clubroot on Chinese cabbage when compared to the control. The above-described results indicate that the strain T-9 may have the potential as an antagonist to control various phytopathogenic fungi.

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1803-1806
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• 2007

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.784-787
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• 2008

Antifungal activity of ChiCW and synergistic interactions between ChiCW with fungicides were investigated. Conidial germinations of phytopathogenic fungi, Alternaria brassicicola, Botrytis elliptica, and Colletotrichum gloeosporioides, were inhibited by ChiCW but A. longipes was not. In addition, ChiCW showed synergistic effect with fungicides Switch (cyprodinil+fludioxonil) and tebuconazole to inhibit fungal conidial germinations. The level of synergism of ChiCW with tebuconazole was higher than that with Switch. The results indicate that ChiCW may exhibit a higher level of synergism with fungicides that have a primary effect upon membranes.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.281-286
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• 2010

A Pseudomonas fluorescens strain was isolated and found to show antagonistic activity against phytopathogenic fungi and to possess a gene responsible for production of antibiotic 2,4-diacetylphloroglucinol. For the extension of biocontrol range, a gene for an Androetonus australis Hector insect toxin 1 (AaHIT1), one of the most known toxic insect-selective peptides, was designed and synthesized according to the preferred codon usage of Pseudomonas fluorescens, cloned, and transformed into the strain by pSUP106 vector, a broad-host-range plasmid. Bioassays indicated that the engineered strain was able to produce AaHIT1 with insecticidal activity, and at the same time retain the activity against plant pathogen. The experiments for nonplanted soil and rhizosphere colonization showed that, similar to the population of the wild-type strain, that of the engineered strain remained relatively constant in the first 10 days, and the subsequent 50 days, suggesting that AaHIT1 expression in the bacterial cell does not substantially impair its long-term colonization. It is first reported that a Pseudomonas fluorescens strain expressing an active scorpion neurotoxin has dual activity against phytopathogenic fungi and insects, making at attractive for agronomic applications.

• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.40-45
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• 1998

An antagonistic fungus inhibiting growth of various phytopathogenic fungi was isolated from greenhouse soils and identified. Mophological features of fruiting structures on potato dextrose agar and colorless globose to ovate heavy walled hyaline cells from the vegetative mycelium grown on MY20 agar indicate that this antagonist is Aspergillus terreus. The antagonistic activity is due to the production of antifungal compounds. An antifungal compound was purified from its culture filtrate using chloroform extraction, column chromatography, and thin layer chromatography. The purified antibiotic was effective to various phytopathogenic fungi and identified as butyrolactone I. $ED_{50}$ values measured by petri-plate assay through effective dosage(ED)-probit analysis were 9.7, 13.7, 23.3, 42.6 and 102.7 ppm on Botrytis cinerea, Rhizoctonia solani, Pythium ultimum, Phytophthora capsici, and Fusarium oxysporum, respectively.