• Research in Plant Disease
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• v.24 no.3
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• pp.221-232
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• 2018

Rhizobacteria play important roles in plant growth and health enhancement and render them resistant to not only biotic stresses but also abiotic stresses, such as low/high temperature, drought, and salinity. This study aimed to select plant growth promoting rhizobacteria (PGPR) with the capability to mitigate biotic and abiotic stress effects on tomato plants. We isolated a novel PGPR strain, Variovorax sp. PMC12 from tomato rhizosphere. An in vitro assay indicated that strain PMC12 produced ammonia, indole-3-acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, which are well-known traits of PGPR. The aboveground fresh weight was significantly higher in tomato plants treated with strain PMC12 than in non-treated tomato plants under various abiotic stress conditions including salinity, low temperature, and drought. Furthermore, strain PMC12 also enhanced the resistance to bacterial wilt disease caused by Ralstonia solanacearum. Taken together, these results indicated that strain PMC12 is a promising biocontrol agent and a biostimulant to reduce the susceptibility of plants to both abiotic and biotic stresses.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1150-1157
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• 2011

Streptomyces sampsonii KK1024 having strong chitinolytic activity was isolated from crab-shell rich soil at Muan, Jeolanamdo. The KK1024 produced chitinase, protease, gelatinase and lipase. When 50% of KK1024 culture broth was treated to juveniles and eggs of root-knot nematode, juvenile mortality at 3 days was 81.67% and egg hatch rate at 5 days was 2.00%. When $183.7{\mu}g\;mL^{-1}$ of crude enzyme produced by KK1024 was treated, juvenile mortality at 3 days was 96.00% and egg hatch rate at 5 days was 5.33%. At 1% of butanol extract from KK1024, juvenile mortality was highest with 90.00% and egg hatch rate was lowest with 0%. The comparison of the effect of KK1024 culture broth with only medium, synthetic fertilizer, and commercial nematicide on tomato growth and nematode infection was examined in pot trials. KK1024 culture broth showed lower number of egg mass and gall in plant, and population of juveniles in soil compared with only medium and synthetic fertilizer treatment, but not in commercial nematicide. However, the highest shoot weight and length was discovered in KK1024 culture broth. These results suggest that Streptomyces sampsonii KK1024 producing lytic enzymes and nematicidal compounds can be one of candidates for biocontrol agents against root-knot nematodes.

• Korean Journal of Organic Agriculture
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• v.6 no.2
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• pp.117-125
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• 1998

For isolation of antagonistic fungi antagonistic to Phytophthora capsici, a total of 157 isolates of fungi were screened from soil. Among the 157 isolates further screened by the dual culture test on potato dextrose agar and V-8 juice agar, 16 isolates were tested to show their antagonistic activity against P. capsici and Fusarium oxysporum. Fungal cul-ture filtrates of screened 16 isolates were shown to inhibit germination of zoospoorangia of P. capsici entirely and conidia of F. oxysporum considerably. Antagonistic fungi were shown to suppress of P. capsici infection of red-pepper plants maintained in the green house. Four isolates. 27 J5, 37 J10, 36 J13 and 31 K10, with the reduced disease incidence 53.3∼60.0% were identified as Fusarium sp. (27 J5). Trichoderma sp. (37 J10, 36 J13) and Penicillium sp. (31 K10).

• 한국약용작물학회:학술대회논문집
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• 2008.11a
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• pp.350-351
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• 2008

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.91-97
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• 1995

The 543 microbial strains were isolated from the rhizosphere in ginseng root rot-suppressive soil. From these, isolate KGM-100 was finally selected for the screening of powerful antagonistic bacterium for the soil-born Fusarium solani causing root rot of many important crops. The isolate KGM-100 was identified as Pseudomonas aeruginosa. Antibiotics produced by the P. aeruginosa KGM-100 were partially characterized as heat-stable and low-molecular weight antibiotics. The strain also produced siderophore, which was assumed to be pseudobactin. Pot test showed approximately 30-50% biological control effects when Fusarium solani-infected soil was treated with the P. aeruginosa KGM-100.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.243-248
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• 1995

Agrochemicals for the plant-disease control are criticized severely for causing environmental pollution and residual problems, and consequently microbial disease control agents are expected to be safer and more economical for sustainable agriculture. Treatment of biological control agents to seed requires the use of effective delivery systems that allow full expression of the benefical qualities of the bioprotectant. For the activation and establishment of bioprotectant around the plant seed which are able protect the seeds and seedlings from pathogen attack, the optimal liquid coating formulation was obtained using 2% sodium carboxymethyl cellulose (binder), 20% sesame dregs (solid particulate material), and dried spore of Bacillus subtilis YBL-7 (bioprotectants, 10 mg/g of seed). Suppressive of root rot was demonstrated in pot trials with coated kidney bean (Phaseolus vulgaris L.) seeds. Coated seeds with B. subtilis YBL-7 spore in F. solani-infested soil reduced disease incidence by 85% to 90% after 30 days.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.169-175
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• 1996

콩 불마름병균 Xanthomonas campestris pv. glycines 8ra는 X. c. pv. vesicatoria에 길항력이 있는 bacteriocin인 glycinecin을 생성 분비한다. Bacteriocin 생성 분비 능력이 있는 콩 불마름병균을 효과적인 생물학적 방제원으로 활용하기 위해서는 좀더 체계적인 연구가 필요하여, bacteriocin 생성에 관계되는 유전자의 분리를 시도하였다. 약 2,000개의 Xanthomonas campestris pv. glycines 8ra cosmid library에서 bacteriocin의 생성 분비 능력을 조사하여 다섯 개의 clone을, pG011, pG0113, pG33과 pG35, 선발하였다. 그중 한 clone pG08을 임의로 선택하여 plasmid DNA를 분리하였다. Plasmid pG08에서 약 6.0 kb의 DNA를 떼어내어 다른 plasmid vector에 넣은 subclone pBL5는 bacteriocin의 생성 분비 능력이 있었다. Plasmid pG08을 제한효소 처리후 다시 접함시켜 만든 몇 개의 subclone과 pBL5의 제한효소 지도를 비교 분석한 결과 약 3.0 kb의 BamHI-HindIII 부분의 DNA가 bacteriocin의 생성에 관계함을 알았다.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.245-250
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• 1996

식물병원균 Botrytis cinerea와 Fusarium oxysporum에 대한 생물학적 방제의 기초자료를 얻기 위하여 살충성 진균 Beauveria bassiana의 식물병원균에 대한 균사성장저해, 포자발아 억제, 균사와 포자의 형태변화 등의 효과를 살펴보았다. 평판배지 상에서 두 식물병원균의 균사생장이 저해되었으며, 저해효과는 배지종류에 따라 달랐는데 B. cinerea의 경우 PDA배지에서 가장 크게 저해되었으며 F. oxysporum의 경우에는 TSA배지에서 가장 크게 저해되었다. B. bassiana는 $25^{\circ}C$에서 6일간 배양했을 때 F. oxysporum에 대한 항균력이 가장 높았으며 동시에 최대의 균체량을 생산하였다. 또한 B. bassiana의 배양여액을 식물병원균에 30% 농도로 첨가하여 배양했을 때 식물병원균의 포자 발아율은 B. cinerea, F. oxysporum에서 각각 30%(control: 88.2%), 10.0%(control: 78.6%)로 낮아졌으며 발아 개시 시간도 4~8시간 지연되었다. 현미경을 통한 미세구조관찰에서는 10%의 B. bassiana배양여액을 첨가했을 때 F. oxysporum의 포자 크기가 1/2~1/3으로 줄어들었으며 균사와 격막의 형태도 비정상적으로 변하여 균사외막과 격막-격막 사이의 구분이 불명확해졌다.

• Journal of the korean veterinary medical association
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• v.38 no.4
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• pp.305-316
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• 2002

동물용의약품은 가축질병의 예방 및 치료의 목적으로 이용되어 그동안 우리나라 가축의 질병방제와 사료효율의 증진으로 양축농가의 소득증대와 아울러 축산이 대규모로 발전할 수 있게 하는데 기여한 바가 크다. 그러나 특히 항생제나 합성 항균제의 오남용에 따른 가축의 장내 세균과 병원성 세균의 항생항균제에 대한 내성획득으로 질병치료 효과의 저하, 축산식품을 통하여 이들 제제의 잔류물질이 인체내로 들어가 부작용을 일으키거나 세균의 내성인자가 사람 병원체에 전달되어 사람의 질병치료에 장애요인이 될 수 있는 문제점이 제기되고 있다. 그리고 공중위생전인 측면에서 항생항균제, 호르몬제, 생물학적제제(백신 등), 마취제, 마약류, 등의 요주의동물용의약품을 체계적으로 관리할 필요성이 제기되고 있다. 본 주제에서는 동물용의약품 중 현재 가장 많은 량이 이용되고 있는 항생제를 중심으로 사용실태와 오남용 사례를 살펴보고자 한다.

• 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.