• Mycobiology
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• 제36권4호
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• pp.236-241
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• 2008

The colonization of an arbuscular mycorrhizal fungus Glomus intraradices BEG110 in the soil caused a decrease in disease severity in cucumber plants after fungal inoculation with Colletotrichum orbiculare. In order to illustrate the resistance mechanism mediated by G. intraradices BEG110, infection patterns caused by C. orbiculare in the leaves of cucumber plants and the host cellular responses were characterized. These properties were characterized using transmission electron microscopy on the leaves of cucumber plants grown in soil colonized with G. intraradices BEG110. In the untreated plants, inter- and intra-cellular fungal hyphae were observed throughout the leaf tissues during both the biotrophic and necrotrophic phases of infection. The cytoplasm of fungal hyphae appeared intact during the biotrophic phase, suggesting no defense response against the fungus. However, several typical resistance responses were observed in the plants when treated with G. intraradices BEG110 including the formation of sheaths around the intracellular hyphae or a thickening of host cell walls. These observations suggest that the resistance mediated by G. intraradices BEG110 most often occurs in the symplast of the host cells rather than in the apoplast. In addition, this resistance is similar to those mediated by biotic inducers such as plant growth promoting rhizobacteria.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.102.1-102
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• 2003

A bacterial strain YC4963 with antifungal activity against Colletotrichum orbiculare, a causal organism of cucumber anthracnose was isolated from the rhizosphere soil of Siegesbeckia pubescens (Siegesbeckia pubescens Makino；Family：Compositae) in Korea. Based on physiological and biochemical characteristics and 16S ribosomal DNA sequence analysis, the bacterial strain was identified as Pseudomonu aureofaciens. The bacteria also inhibited mycelial growth of several plant fungal pathogens such as Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani on PDA and 0.1 TSA media. The antibiotic activity was found from the culture filtrate of TSB(tryptic soy broth) and its active compounds were quantitatively bound to XAD adsorber resin. The antibiotic spectrum was broad and growth of C. orbiculare and F. oxysporum, B. cinerea were inhibited at very low concentration. The chemical data from various chromatographic procedures showed that active fraction consisted of at least two phenazine derivatives. However, the metabolites had no inhibitory effect on Pythium ultimum which was reported to be sensitive to phenazine antibiotics. The compounds responsible for the activity are now under investigation.

• 한국환경농학회지
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• 제29권1호
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• pp.86-91
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• 2010

This study was carried out to assess the antifungal potential of R. oligosporus and its ethyl acetate (EtOAc) extract against the fungal pathogens causing anthracnose disease in apple fruits using disc diffusion, antagonistic effect and morphological abnormalities in fungal mycelia. The percentage of inhibition of antifungal effect of the ethyl acetate extract (5 ${\mu}l$ $disc^{-1}$) of the R. oligosporus against C. acutatum KACC 40848, C. gloeosporioides KACC 40897, C. higginsianum KACC 40806, C. orbiculare KACC 40808, C. coccodes KACC 40008, C. musae KACC 40947, C. boninense KACC 40893, C. liliacearum KACC 40981, C. caudatum KACC 41028 and Colletotrichum sp. KACC 40811 was found to be 44.4, 35.5, 40, 31.1, 33.3, 37.7, 40, 51.1, 28.8 and 28.8%, respectively. Also the fungus R. oligosporus showed potential antagonistic effect of antifungal activity against the tested pathogens of Colletotrichum spp. Further, R. oligosporus had a potential detrimental effect on the morphology of the tested fungi of Colletotrichum spp. such as wrinkle abnormalities, abnormal cell formation, lysis of mycelium, empty cell formation, distorted cell formation and breakage of the mycelium. These findings strongly support the role of R. oligosporus to serve as a potential antifungal agent to control plant pathogenic fungi causing anthracnose disease in apple fruits.

• 농약과학회지
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• 제12권4호
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• pp.307-314
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• 2008

Thymol(I), 5-isopropyl-3-methylphenol(II), 4-isopropyl-3-methylphenol(III), 2-sec-butylphenol(IV)과 4-sec-butylphenol(V)을 출발물질로 하여 alkylphenyl fluorobenzoate계 ester 유도체 60종을 합성하였다. 이 유도체들의 합성은 IR, $^1H$-NMR과 GC/MS를 이용하여 확인하였다. 이들 화합물들에 대하여 토마토 역병균, 오이 잿빛곰팡이병균, 오이 탄저병균과 벼 잎집무늬마름병균에 대한 항균활성을 조사하였다. 오이 잿빛곰팡이병균에 2-sec-butylphenyl 2,5-difluorobenzoate (IV-6)와 4-sec-butylphenyl 2,5-difluorobenzoate(V-6)등이 90% 이상의 우수한 항균활성을 나타내었다. 오이 탄저병균에 대하여 2-isopropyl-5-methylphenyl 2,3,6-trifluorobenzoate(I-11), 2-isopropyl-5-methylphenyl 2,4,5-trifluorobenzoate(I-12), 5-isopropyl-3-methylphenyl 2,3,6-trifluorobenzoate(II-11), 4-isopropyl-3-methylphenyl 2,3,6-trifluorobenzoate(III-11)와 4-isopropyl-3-methylphenyl 2,4,5-trifluorobenzoate(III-12)가 90% 이상의 매우 우수한 항균활성을 나타내었다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2002년도 총회 및 추계학술발표회
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• pp.55.1-55
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• 2002

• Mycobiology
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• 제28권4호
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• pp.190-192
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• 2000

Antifungal bacteria for biological control of plant diseases or production of novel antibiotics to plant pathogens were isolated in 1997 from various soils of Ansung, Chunan, Koyang, and Paju in Korea. Sixty-four bacterial strains pre-screened from approximately 1,400 strains were tested on V-8 juice agar against eight plant pathogenic fungi using in vitro bioassay technique for inhibition of mycelial growth. Test pathogens were Alternaria mali, Colletotrichum gloeosporioides, C. orbiculare, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. lycopersici, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. A wide range of antifungal activity of bacterial strains was found against the pathogenic fungi, and strain RC-B77 showed the best antifungal activity. Correlation analysis between inhibition of each fungus and mean inhibition of all eight fungi by 64 bacterial strains revealed that C. gloeosporioides would be best appropriate for detecting bacterial strains producing antibiotics with potential as biocontrol agents for plant pathogens.

• 한국산학기술학회논문지
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• 제11권12호
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• pp.4854-4862
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• 2010

본 연구에서 thyme oil의 주성분인 thymol (1)과 유사한 구조를 갖는 4-isopropyl-3-methylphenol (2), 5-isopropyl-3-methylphenol (3), 4-isopropylphenol (4)과 2-isopropylphenol (5)을 출발 물질로 하여 sulfonyl ester 계열 유도체 25종을 합성하였다. IR, $^1H$-NMR과 GC/MS를 이용하여 이들 유도체들이 합성되었음을 확인하였다. 이들 유도체들에 대한 식물병원균의 생장 억제실험은 벼도열병균(Pyrcularia grisea), 벼잎집무늬마름병균(Rhizoctonia solani), 토마토잎마름역병균(Phytophthora infestans), 오이탄저병균(Colletotrichum orbiculare)과 오이흰가루병균(Sphaerotheca fusca)에 대하여 실시하였다. 그 결과, 2-isopropyl-5-methylphenyl o-toluenesulfonate (1a), 2-isopropylphenyl 2,4,5-trich lorobenzenesulfonate (5b)와 2-isopropylphenyl 2-methyl-5-nitrobenzenesulfonate (5e)는 각각 in vivo에서 벼도열병균(Pyrcularia grisea), 토마토잎마름역병균(Phytophthora infestans)과 오이흰가루병균(Sphaerotheca fusca)에 대하여 우수한 항균활성을 나타내었다.

• 한국환경농학회지
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• 제20권1호
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• pp.57-62
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• 2001

여러 작물 재배지 토양에서 각종 근권미생물을 분리하여 이들 분리미생물 중 수박 만할병균인 Fusarium oxysporum f. sp. niveum(KCCM34741)에 길항하는 미생물인 YJ-19, YJ-45, YJ-3 등 12 균주를 분리하였다. 길항미생물들은 MS agar 배지 실험 및 미생물제제 첨가 상토 실험에서 모두 참박의 발아율을 향상시켰으며, 이들 중 분리주 YJ-3 균주는 참박의 발아율과 초기생육에 가장 큰 영향을 주는 미생물로 선별되었다. YJ-3 균주를 제제화하여 참박 재배 기간별로 식물체 생육실험을 행한 결과 대조구인 일반 상토 및 시판 미생물혼합 상토 보다 각각 46%와 13%정도 생육을 촉진하는 것으로 나타났다. 분리주 YJ-3 균주는 간균의 gram 양성균으로서 Bacillus sp.로 동정되었다. Bacillus sp. YJ-3은 수박 만할병균인 F. oxysporum f. sp. niveum에 대해 강한 억제효과를 나타내었고, 그외 수박 병원균인 Alternaria cucumerina, Botrytis cinerea, Colletotrichum orbiculare, Didymella bryoniae, Rhazoctonia solani 등에서도 우수한 길항력을 나타내어 본 Bacillus sp. YJ-3 균주는 수박 만할병균에 길항하는 동시에 참박의 생육을 촉진하는 미생물로 확인되었다.

• 한국균학회지
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• 제32권1호
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• pp.31-38
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• 2004

오이 뿌리조직으로부터 분리한 식물내생세균 EB215균은 탄저병균인 Colletotrichum species에 대하여 강한 항균활성을 보였다. 이 균은 생리 생화학적 특성과 Biolog 실험 및 16S rDNA 유전자 서열에 의해 Burkholderia cepacia로 동정되었다. 이 균의 항균물질 생산을 위한 최적배지는 nutrient 액체(NB) 배지로 그리고 배양기간은 3일로 결정되었다. B. cepacia EB215 균주의 NB 배양체로부터 원심분리, n-hexane 분획, silica gel 컬럼, preparative TLC 및 in vitro 생물검정 등을 통하여 한 개의 항균물질을 분리하였다. 이 물질은 질량분석과 핵자기공명 분석을 통하여 pyrrolnitrin으로 동정되었다. Pyrrolnitrin은 고추 탄저병(Colletotrichum coccodes), 오이 탄저병(Colletotrichum orbiculare), 벼 도열병(Magnaporthe grisea), 벼 잎집무늬마름병(Corticium sasaki) 등의 4가지 식물병에는 $11.1\;{\mu}g/ml$ 낮은 농도에서도 90% 이상의 높은 방제활성을 보였다. 그리고 또한 토마토 잿빛곰팡이병(Botrytis cinerea)과 밀 붉은녹병(Puccinia recondita)에 대해서는 $33.3\;{\mu}g/ml$ 이상의 농도에서 90% 이상의 방제활성 보였다. 하지만 Phytophthora infestans에 의한 토마토 역병에 대해서는 전혀 항균활성이 없었다. 앞으로 B. cepacia EB215균을 이용한 미생물살균제 개발에 대하 연구를 진행할 예정이다.

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2627-2634
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• 2012

Strobilurins are one of the most important classes of agricultural fungicides. To discover new strobilurin derivatives with high activity against resistant pathogens, a series of novel ${\beta}$-methoxyacrylate analogues were designed and synthesized by integrating substituted pyrimidine with a strobilurin pharmacophore. The compounds were confirmed and characterized by infrared, $^1H$ nuclear magnetic resonance, elemental analysis and mass spectroscopy. The bioassays indicated that most of the compounds (1a-1h) exhibited potent antifungal activities against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian at the concentration of 50 ${\mu}g/mL$. Exhilaratingly, compound 1d (R=3-trifluoromethylphenyl) showed better antifungal activity against all the tested fungi than the commercial strobilurin fungicide azoxystrobin.