• Applied Biological Chemistry
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• v.48 no.1
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• pp.34-39
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• 2005

There are various crop diseases in green houses that are caused by the cultural environments, especially high temperature and moisture. To solve the forementioned problems, farmers are overusing agricultural chemicals, causing other damages by the chemical residue. In this study, antagonistic bacteria as biological control agents were isolated to produce the environmentally-friendly crops for use in green houses. Eighteen species of antagonistic bacteria were totally isolated from the soil and plants in the Perilla fields, and AK-17 showed the highest activity among the isolates. According to the results of anti-fungal spectrum against several pathogens by AK-17, the antagonism effect of the isolates was remarkable against grey mold rot by Botrytis cinerea, sclerotinia rot by Sclerotnia sclerotiorum, and stem rot by Rhizoctonia solini. To evaluate the biological control effects of the isolates against the major diseases of Perilla, studies were carried out to evaluate the preventive and the curative effects of the diseases throughout the pot experiments. According to the forementioned experiments, the preventive and the curative effects by the isolates against sclerotinia rot were respectively showed as 55% and 92%. For the grey mold rot, those were 40% and 78%, respectively. As to the evaluation of the growth-promoting effect by AK-17, the length and the biomass of the tested plants were increased to 120% and to 164%, respectively. For the leaf numbers and area were respectively increased to 120% and 220%. Furthermore, AK-17 was identified as Burkhoderia sp. according to the results of physiological properties and genetic methods.

• 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.

• Korean Journal of Organic Agriculture
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• v.22 no.2
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• pp.269-280
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• 2014

This study was performed to test the insecticidal and antimicrobial activity of plant extracts from clove, Sophora flavescens Aiton and neem. As the result of antimicrobial activity test, clove extract showed the strongest activity against Botrytis cinerea. In insecticidal activity test, the extract of Sophora flavescens Aiton was the highest against Nilaparvata lugens. The pyroligneous liquor (10%) and emulsified spreader (10%) were added to the extracts of clove and Sophora, respectively, to apply the environment-friendly rice field. In the field treated clove extract, disease damage occurred 49.1% and insect damage occurred 29.5% compared to control plot (100%). In the field treated Sophora extract, disease damage was 56.7% and insect damage was 21.0% compared to control plot (100%). In conclusion, plant extracts from Sophora and clove could control about 50% of disease and about 70% of insect damage that they could be used as environment-friendly resources to control disease and insect in rice farming.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.68-74
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• 2004

Miscanthus purpurascens Juice containing potassium (37,952 mg/L), nitrogen (14,000 mg/L), phosphorus (6,800 mg/L), magnesium (5,969 mg/L), calcium (5,910 mg/L), etc., was investigated to develop a novel meidum far the mass cultivation of useful microorganisms. For this research, we first isolated an antagonistic bacterium G-74 from soil, which showed strong growth inhibition against two phytopathogenic fungi, Rhizoctonia solani and Botrytis cinerea, and identified as Bacillus lentimorbus G-74 based on the morphological characteristics and MIDI analysis. Culture conditions for G-74 strain in the M. purpurascens juice medium were optimized. Dilution rate of the medium, temperature and initial pH for the optimum growth of G-74 strain were 30% (V/V), $35^{\circ}C$ and 5.0, respectively. It was found that additions of 2.0% (W/V) corn starch as a carbon source and 1.0% (W/V) yeast extract as a nitrogen source in this medium increased B. lentimorbus G-74 growth to 66% more efficient than Luria Bertani medium.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.359-363
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• 1995

New ten N-[1-(benzotriazol-1-yl)alkyl]aniline(4) derivatives were synthesized and the crystal structure of 4h was shown by X-ray crystallography and the absolute configuration has been assigned as S form. The molecule crystallizes in the monoclinic system, space group $P2_{1}/n$. And the molecules in the crystal are linked with each other through the hydrogen bond $(N_{11}-H_{11}{\cdots}N3)$ with distance $2.300(11){\AA}$ The fungicidal activity($pI_{50}$) in-vitro against Botrytis cineria (BC), Phytophthora casici (PC) and Sclerotium cepinorum (SC) were determined by the agar dilution method. The structure activity ralationships (SAR) between structure of 4 and the activity were studied using a physicochemical parameters of substituents and multiple regression technique. Among these compounds, only the bromo group substituent(4f) showed higher activity, which depend on the hydrophobic(${\pi}$) of substituents. The relative orders of the activity are SC>BC> and PC, respectively. This implies that the activity is affected by the hydrophobic(${\pi}$) nature of the Z group rather than the X group. Linear free energy relationships(LFER) on the fungicidal activity with substituents has been also discussed.

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.158-164
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• 1995

토마토의 엽권에서 분리한 Fusariym graminearum이 분비하는 물질은 벼 도열병균(Pyricularia oryzae)의 여러 종의 식물병원 진균에 대한 항균활성을 나타내었으며, 이러한 활성물질을 PDA에서 본 균을 배양 한 후 chloroform으로 추출하여 분리정제 하였다. HPLC에 의하여 5종류의 활성 물질을 분획하였으며, 그중 1번(F402) 화합물을 벼 도열병균(P. oryzae)을 포함한 22개 식물 병원 진균에 대하여 살균 활성범위를 조사한 결과, 이 화합물은 50$\mu\textrm{g}$/ml 농도에서 Pythium ultimum, Rhizoctonia solani, Sclerotinia sclerotiorum은 전혀 억제하지 못하였으며, Phytophthora spp., Cladosporium fulvum, Fusarium spp., Corynespora cassicola에는 어느 정도의 활성이 있었지만 낮게 나타났고, P. oryzae, Cochliobolus miyabeanus, Alternaria solani는 100% 억제하여 활성이 높게 나타났다. 또한 장내 세균에 대한 활성을 MIC로 비교할 때 Streptococcus pyogenes, Streptococcus faecium에 대하여는 각각 12.5, 25 $\mu\textrm{g}$/ml였고 Staphylococcus aureus는 25-50$\mu\textrm{g}$/ml으로 나타났으며, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella aerogenes, Enterobacter cloacae에서는 100$\mu\textrm{g}$/ml 이상으로 활성이 나타나지 않았다. F402를 200$\mu\textrm{g}$/ml의 농도로 직접 살포한 식물체에서의 방제효과는 벼도열병, 벼 깨씨무늬병, 보리 흰 가루병에 대하여는 80%이상이었으나, 벼 잎집무늬마름병, 오이 잿빛곰팡이병, 토마토 역병, 밀 녹병에서는 낮았다.

• The Korean Journal of Mycology
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• v.23 no.3 s.74
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• pp.246-256
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• 1995

Phenotypic characteristics, pathogenicity and fungicides resistance of fifty one isolates of Botrytis cinerea obtained from various host plants were observed and determined. The relationships between these characteristics were also investigated on the basis of isolation host plants. The isolates of B. cinerea varied in the capacity of sclerotia formation and sporulation. The pathogenicity of 44 isolates from tomato, cucumber, and strawberry was significantly stronger with 3.2 cm in average diameter of necrotic lesions on cucumber leaves than that of seven isolates from other host plants such as orange, gerbera, ginseng, kiwi, grape, pear and from butter with 1.8 cm in average diameter of necrotic lesions. Benomyl resistance of 12 isolates from tomato plants was much higher with the $EC_{50}$, 562 ppm than that of 19 isolates from various host plants. Diethofencarb resistance, however, of 11 isolates from strawberry plants was highest with the $EC_{50}$, 210 ppm among isolates from other host plants. Polygalacturonase activity varied among isolates in the range of 0 to 103 unit and that of isolates from tomato, cucumber and strawberry was slightly lower than that of isolates from other host plants. No significant relationship between pathogenicity and fungicides resistance, polygalacturonase activity was found among 51 isolates of B. cinerea. Isozyme patterns of polygalacturonase produced from two strongly and weakly pathogenic isolates (FC122, KC6) were slightly different depending upon carbon sources during cultivation.

• Research in Plant Disease
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• v.18 no.3
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• pp.217-224
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• 2012

Post-harvest rot of grape causes a severe economic loss and lower of the grape quality. It is also one of the important limiting factors for grape export. Grape rots and their casual agents on 'Red Globe' variety imported from Chile were identified. Grapes shown rotting symptom were collected from the storages near the import harbor. The 3 different rots were identified on the imported 'Red Globe'; melting decay, gray mold, and blue mold. A bacterium that isolated from a typical melting decay symptom was identified as Gluconobacter cerinus on basis of its nucleotide sequence of 16S rDNA and fatty acid profile. By inoculation on grape, it caused cracking and dissolution of epidermis of grape which were the characteristics of melting decay. Botrytis cinerea and Penicillium expansum were isolated from grapes showing gray mold and blue mold. The 2 fungal isolates were identified on basis of their morphological characteristics and nucleotide sequence of their beta-tubulin genes. They showed strong pathogenicity on 'Campbell Early' variety that is a major table grape in Korea.

• Journal of Life Science
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• v.25 no.12
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• pp.1408-1414
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• 2015

In this study, to retain a stable bacterial inoculant, Bacillus strains showing antifungal activity were screened. The improved production, antifungal mechanism, and stability of the antifungal metabolite by a selected strain, AF4, a potent antagonist against phytopathogenic Botrytis cinerea, were also investigated. The AF4 strain was isolated from rhizospheric soil of hot pepper and identified as Bacillus subtilis by phenotypic characters and 16S rRNA gene analysis. Strain AF4 did not produce antifungal activity in the absence of a nitrogen source and produced antifungal activity at a broad range of temperatures (25-40℃) and pH (7-10). Optimal carbon and nitrogen sources for the production of antifungal activity were glycerol and casein, respectively. Under improved conditions, the maximum antifungal activity was 140±3 AU/ml, which was higher than in the basal medium. Photomicrographs of strain AF4-treated B. cinerea showed morphological abnormalities of fungal mycelia, demonstrating the role of the antifungal metabolite. The B. subtilis AF4 culture exhibited broad antifungal activity against several phytopathogenic fungi. The antifungal activity was heat-, pH-, solvent-, and protease-stable, indicating its nonproteinous nature. These results suggest that B. subtilis AF4 is a potential candidate for the control of phytopathogenic fungi-derived plant diseases.

• Food Science and Preservation
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• v.10 no.2
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• pp.224-229
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• 2003

This study was carried out to isolate of antagonistic bacterium to Allium cepa L. pathogens. A total of 250 strains were isolated from A. cepa L. roots. The isolates were screened for antagonism to A. cepa L. pathogens and the isolated strain No. YJ-4 was selected among these bacteria. It was identified as Bacillus ehimensis based on morphological and physiological characteristics according to the Bergey's mannual of systematic bacteriology, Sherlock system of Microbial ID Int and 165 rDNA sequences methods. Bacillus ehimensis YJ-4 showed broad spectrum of antibacterial and antifungal activities against plant pathogens as Alternaria porri, Botrytis cinerea, Erwinia carotovora subsp. carotovora Fusarium of oxysporium, penicillium sp., Pseudomonas sp., Rhizoctonia solani, Sclerotium cepivotum, Septoria sp., Stemphylium botryosum. Speially B. ehimensis YJ-4 showed high antifungal activity on growth against F. oxysporium, the causal agent of onion Fusarium wilt.