• Korean Journal of Organic Agriculture
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• v.12 no.1
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• pp.101-114
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• 2004

This study was carried out to clarify the effects of antagonistic microorganism, Bacillus sp. JC181 isolated from the greenhouse soil grown cucumber plants on the growth inhibition of plant pathogen, fusarium wilt (Fusarium oxysporum) occurred in cucumber plants in greenhouse. Antagonistic bacterial strains were isolated and were investigated into the antifungal activity of the antagonistic microorganism against fusarium wilt. Screened fourteen bacterial strains which strongly inhibited F. oxysporum were isolated from thc greenhouse soil grown cucumber plants, and the best antagonistic bacterial strain designated as JC181, was finally selected. Antagonistic bacterial strain JC181 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. Bacillus sp. JC181 showed 58.2% of antifungal activity against the plant pathogen growth of F. oxysporum. By the bacterialization of culture broth and heated filtrates of culture broth, Bacterial strain, Bacillus sp. JC181. showed 91.2% and 260% of antifungal activity against F. oxysporum, respectivrly.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.93.2-94
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• 2003

In our previous studies, we selected three antagonistic bacteria, KJ1R5, KJ2C12, and KJ9C8 against Phytophthora capsici, the casual agent of Phytophthora blight of pepper. For elucidating production, root colonization, and total microbial activity were investigated. The dual culture assay was accomplished to elucidate existence of antibiotics. In this assay, any antagonistic bacteria did not inhibit growth of six important fungal plant pathogens, suggesting that these antagonists do not produce antibiotics. root surface or rhizosphere soil colonizations were examined with spontaneous rifampicin-resistant mutants equal to antagonistic ability of wild types. KJ2C12 colonized consistently rhizosphere soil while yellowish colonies of KJ1R5 and KJ9C8 well colonized root surfaces and rhizosphere soil. Total microbial activity in pots treated with the antagonistic bacteria was measured using fluorescein diacetate hydrolysis. total microbial activity of three antagonistic bacteria treatments was significantly higher than that of buffer-treated control until 4days after treatment. However, total microbial activity of treatment of three antagonistic bacteria decreased after 7 days. These results indicate that the antagonistic bacteria, KJ1R5 and KJ9C8 colonized and protected roots well against Phytophthora blight of pepper through competition of infection courts, especially competitions.

• Korean Journal of Organic Agriculture
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• v.11 no.4
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• pp.61-74
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• 2003

This study was conducted to screen the antagonistic bacteria which inhibit the growth of plant pathogen, fusarium wilt(Fusarium oxysporum) occurred in tomato plants in greenhouse. We isolated an effective bacterial strains and investigated into the antifungal activity of the antagonistic microorganism and it’s identification. Ten bacterial strains which strongly inhibited Fusarium oxysporum were isolated from the nature, and the best antagonistic bacterial strain designated as KC175, was selected. The antagonistic strain KC175 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. The Bacillus sp. KC175 showed 58.2% of antifungal activity against the growth of Fusarium oxysporum. By the bacterialization of the culture broth and the heat bacterialization culture filtrate of it, Bacillus sp. KC175 showed 91% and 18% of antifungal activity, respectively.

• Korean Journal of Organic Agriculture
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• v.13 no.2
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• pp.161-173
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• 2005

This study was carried out to clarify the effects of antifungal bacterial strains isolated from the greenhouse soil grown strawberry plants on the growth inhibition of plant pathogen, gray mold (Botrytis cinerea) infected in strawberry plants in Damyang and Jangheung districts. Antagonistic bacterial strains were isolated and investigated into the antagonistic activity against gray mold. Screened ten bacterial strains which strongly inhibited Botrytis cinerea were isolated from the greenhouse grown strawberry plants, and the best antifungal microorganism designated as SB 143 was finally selected. Antifungal bacterial strain SB 143 was identified to be the genus Bacillus sp. based on the morphological and biochemical characterization. Bacillus sp. SB 143 showed 59.4% of antifungal activity against Botrytis cinerea. By the bacterialization of culture broth and heated filtrates of culture broth, Bacillus sp. SB 143 showed 93.1% and 32.1% of antagonistic activity against Botrytis cinerea.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.346-352
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• 1995

For isolation of antibiotic-producing bacteria antagonistic to Fusarium oxysporum, a total of 327 microorganisms were screened from sesame-growing soils collected at various locations in Korea by the modified Herr's triple-agar-Iayer technique. Among the 36 bacterial isolates further screened by the dual culture test on tryptic soy agar, 10 were tested to show their antagonistic activity against 14 plant pathogenic fungi. Bacterial culture filtrates were shown either to inhibit some phytopathogenic fungal growth or to suppress F. oxysporum infection of sesame plants maintained in the green house. An isolate, B23, with the most prominent antagonistic activity was identified as Bacillus subtilis.

• Korean Journal of Organic Agriculture
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• v.12 no.2
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• pp.183-196
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• 2004

This study was carried out to screen and select the effects of antifungal bacterial strains which inhibit the growth of plant pathogen, Fusarium oxysporum(fusarium wilt) occurred in carnation plants in greenhouse. We isolated an effective bacterial strains and investigated into the antifungal activity of the antagonistic microorganism and it's identification. Twenty bacterial strains which strongly inhibited Fusarium oxysporum were isolated from roots of carnation plants and the soil in greenhouse, and the best antifungal bacteria designated as C121, was finally selected. Antagonistic bacterial strain, C121 was identified to be the genus Bacillus sp. based on the morphological, biochemical and cultural characterizations. The Bacillus sp. C121 showed 58.1% of antifungal activity against the growth of Fusarium oxysporum. By the bacterialization of the cultural broth and the heat bacterialization culture filtrate of it, Bacillus sp. C121 was shown 92.1% and 21.0% of antifungal activity, respectively.

• Journal of Food Hygiene and Safety
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• v.14 no.2
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• pp.167-171
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• 1999

In order to screen the antagonistic bacteria which inhibit the growth of the apple pathogen, Penicillum expansum, we isolated an effective bacterial strain and investigated into the antifungal activity of the antagonist and it's identification. The eleven strains of bacteria which strongly inhibited P. expansum were isolated from the nature, and the best antagonistic bacterial strain designated as CH142, was selected. The antagonistic strain CH142 was identified to be the genus Bacillus subtilis based on morphological and biochemical characterization. The CH142 showed 55.9% of antifungal activity against the growth of P. expansum. By the treatment of the culture broth and the heat treated culture filtrate of it, the B. subtilis CH142 showed 90% and 15% of antifungal activity, respectively.

• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.334-340
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• 2000

In order to select multifunctional powerful antagonistic biocontrol agent against red-pepper rotting fungi Phytophthora capsici, we isolated an indigenous antagonistic bacterium which produces antifungal substances and siderophores from a local soil of Kyongju, Korea. The isolated strain was identified as Pseudomonas fluorescens biotype F. The antibiotic produced from P. fluorescens 2112 inhibited hyphae growth and the zoospore germination of Phytophthora capsici. The favorable carbon, nitrogen source and salts for the production of antibiotic from P. fluorescens 2112 were glycerol, beef extract and LiCi at 1.0%, 0.5% and 5 mM, respectively. And antagonistic activity of P. fluorescens 2112 was confirmed against P. capsici in vivo.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.35-43
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• 1997

For the purpose of acquiring microbial agents that can be utilized to billogically control the major airborne disease to apple trees, such as canker(Valsa ceratosperma), the effective microorgaisms were isolated, tested for antagonistic activity to the pathogen causing major disease to apple trees and identifed. Screening of more than 3, 000 species of microorganisms collected in nature for them antagonistic action to the pathogen, Valsa ceratosperma causing disease to apple tree resulted in selection of effective species. Out of the 11 species, one species designated as CAP141 demonstrated outstanding activity. The bacterial strain, CAP141 exerted antagonistic efficiency of 65% on Valsa ceratosperma. The CAP141 was identified as a bacterial strain to Bacillus subtilis based on morphology, culture conditions, and physio-biochemical characteristics.

• The Korean Journal of Mycology
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• v.20 no.3
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• pp.259-268
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• 1992

Fifty-three actinomycetes antagonistic to Phytophthora capsici and Magnaporthe grisea were isolated from rhizosphere soils in six pepper-growing areas and ashore soils. Thirty-two antagonistic actinomycetes, showing inhibition zone larger than 5 mm, were classified into 20 groups according to their colony morphology and color. The antagonistic activity against P. capsici greatly varied, which showed inhibition zone sizes in the ranges from 5.7 to 17.5 mm on V-8 juice agar and from 2.5 to 17 mm on tryptic soy agar. The antagonistic activity of some actinomycetes tested was remarkably different between the two test media. The antagonists showed a relatively broad antifungal spectrum, but their antibacterial activity was negligible, except for Pseudomonas solanacearum. Butanol extracts of culture filtrates from antagonistic actinomycetes inhibited mycelial growth of P. capsici and M. grisea, thereby confirming strongly antibiotic production in culture. Culture filtrates of some antagonistic actinomycetes completely inhibited Phytophthora blight in pepper plants.