• The Korean Journal of Mycology
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• v.33 no.2
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• pp.86-88
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• 2005

Antifungal activity of the extracts of plants and marine microalgae against Magnaporthe grisea was investigated. Acetone extracts of promegranate rind, leek seed, and maize husk demonstrated high antifungal activity against M. grisea. MIC (minimum inhibitory concentration) of acetone extracts of promegranate rind, leek seed, and maize husk was 100 ng/ml, $50\;{\mu}g/ml,\;and\;100\;{\mu}g/ml$ respectively. Ethanol extract of Amphiprora gigantea showed antifungal activity against M. grisea with MIC of $100\;{\mu}g/ml$.

• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.249-253
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• 1994

Twenty six isolates of Magnaporthe grisea originated from rice and other gramineous hosts Korea were tested for mating type with MAT1-1 and MAT1-2 standard isolates. Ninety three and 64% of rice and grass isolated mated and produced perithecia with standard isolates, respectively. Both mating types were found from rice and non-rice isolates, but MAT1-1 allele of M. grisea was predominant in Korea.

• Korean Journal Plant Pathology
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• v.12 no.4
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• pp.389-394
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• 1996

도열병균, Magnaporthe grisea, 균주간의 유전적 유연관계를 분석하고 그들의 유전에 관한 '기본 정보를 얻고자 DNA polymorphism 분석을 실시하였다. 기주가 다른 도열병 균주들이 공시되었고 cloning에 의해 벼 도열병균 KJ201레이스 균주로부터 생성된 임의 선발 genomic clone들이 공시균주들간의 polymorphism을 밝히기 위해 사용되었던 바 그중 repectitive sequence를 보유한 repeated copy clone 하나가 선발되었다. Clone pMJ6에 의해 밝혀진 repetitive sequence는 Southern hybridization시 벼 분리균주에는 약 30개, 다른 기주 분리균에도 20∼33개의 밴드를 형성하였다. 반면 피 분리균주에는 단지 두 개의 밴드만을 나타내 분리기주가 다른 균주간에 뚜렷한 polymorphism이 존재하였으며 parsimony 분석에서도 역시 아주 먼 cluster를 형성하여 피 분리균은 다른 기주 분리균과 유전적으로 상당히 먼 것으로 추정되었다. 공시균의 genomic DNA를 HindIII로 처리했을 때 pMJ6에 의한 밴드양상은 공시균을 EcoRI으로 처리했을 때의 MGR probe의 밴드 양상과 유사하여 이 repeated copy clone이 도열병균주간의 유전적 유연관계를 분석하는데 MGR 못지않게 유용할 것으로 보인다.

• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.254-260
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• 1994

Magnaporthe grisea, a causal agent of blast, forms a specialized infection structure, an appressorium, to infect host. Hydrophobicity of contact surface and cAMP have been suggested as a primary environmental signal and a second messenger to trigger and mediate appressorium formation in this fungus, respectively. To generalize these factors in field isolates of M. girsea, twenty isolates originated from rice and other gramineous hosts were tested. Seventeen including rice and non-rice isolates formed appressoria on hydrophobic surface, but none of isolates formed appressoria on hydrophilic surface. Eighteen isolates formed appressoria on hydrophilic surface in the presence of IBMX, an inhibitor of phosphodiesterase, except two rice isolates. These results strongly support the hypothesis that appressorium formation by M. grisea is induced by hydrophobic hard surface and regulated by the endogenous level of cAMP in the cells. Understanding fungal development is not only of biological interest but provides new targets for novel disease control strategies.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1158-1162
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• 2006

The glyoxylate cycle can conserve carbons and adequately supply tricarboxylic acid (TCA) cycle intermediates for biosynthesis when microorganisms grow on $C_{2}$ carbon sources. It has been reported that isocitrate lyase (ICL1), a key enzyme of the glyoxylate cycle, is highly induced when Magnaporthe grisea, the causal agent of rice blast, infects its host. Therefore, the glyoxylate cycle is considered as a new target for antifungal agents. A 1.6-kb DNA fragment encoding the ICL1 from M. grisea KJ201 was amplified by PCR, cloned into a vector providing His-tag at the N-terminus, expressed in Escherichia coli, and purified using Ni-NTA affinity chromatography. The molecular mass of the purified ICL1 was approximately 60 kDa, as determined by SDS-PAGE. The ICL1 inhibitory effects of TCA cycle intermediates and their analogs were investigated. Among them, 3-nitropropionate was found to be the strongest inhibitor with an $IC_{50}$ value of $11.0{\mu}g/ml$. 3-Nitropropionate inhibited the appressorium development in M. grisea at the ${\mu}M$ level, whereas conidia germination remained unaffected. This compound also inhibited the mycelial growth of the fungus on minimal medium containing acetate as a $C_{2}$ carbon source. These results suggest that ICL1 plays a crucial role in appressorium formation of M. grisea and is a new target for the control of phytopathogenic fungal infection.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.413-417
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• 1998

Magnaporthe grisea, the casual agent of rice blast, requires formation of an appressorium, a dome-shaped and well melanized infection structure, to penetrate its host. Environmental cues that induce appressorium formation include hydrophobicity and hardness of contact surface and chemicals from its host. Artificial surfaces are widely used to induce appressorium formation, but frequencies of appressorium induction are not always consistent. To understand variable induction of appressorium formation in M. grisea, several factors were tested on GelBond. High levels of appressorium formation were induced over a wide range of temperature (20~3$0^{\circ}C$) and pH (4~7). spore age up to 3-week-old did not significantly affect appressorium formation, but only a few apressoria on GelBond. However, adenosine specifically inhibited appressorium formation. Adenosine inhibition of appressorium formation was restored by exogenous addition of cAMP. Germ tube tips of M. grisea maintained the ability to differentiate appressoria by chemical inducers on GelBond at least up to 16 h after conidia germination. These results suggest that environmental factors have little effect on the variable induction of appressorium formation on the artificial surface in M. grisea.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.1026-1028
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• 2002

Screening tests against fungus causing rice blast, Magnaporthe grisea, were performed in order to develop biopesticides. More than 400 actinomycetes collected at several sites near Hanla Mountain on Jeju Island, Korea were tested, and strain BG2-53 showed potent antifungal activity. The in vivo screening was performed with fermentation broth, and the strain taxon was identified.

• Korean Journal Plant Pathology
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• v.12 no.4
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• pp.453-454
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• 1996

벼, 바랭이, 톨페이스큐로부터 분리한 벼 도열병균에 대한 기주범위를 벼, 밀, 보리, 옥수수, 호밀, 귀리, 톨페스큐 등의 작물과 피, 왕바랭이, 바랭이, 강아지풀, 개기장 등의 잡초를 대상으로 실험하였다. 대부분의 균주들은 공시작물 모두와 잡초인 강아지풀에대하여 병원성을 나타내었다. 이러한 결과는 논 주면의 강아지풀이 벼 도열병균의 기주로 작용할 수 있음을 나타내었다.

• KOGO NEWS
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• v.5 no.1
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• pp.4-4
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• 2005

• The Plant Pathology Journal
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• v.26 no.3
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• pp.280-285
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• 2010

In the course of a searching natural antifungal compounds from plant sources, we found that the methanol extract ($3,000\;{\mu}g/ml$) of Malus domestica fruits had potential of control against rice blast (Magnaporthe grisea) and tomato late blight (Phytophthora infestans). Under bioassay-guided purification, we isolated phloretin, a phenolic compound, with in vivo antifungal activity against M. grisea. By 1-day protective application of phloretin ($500\;{\mu}g/ml$), the compound strongly inhibited the disease development of M. grisea and P. infestans on rice and tomato seedlings, respectively. And red pepper anthracnose caused by Colletotrichum coccodes also was moderately suppressed. However, rice sheath blight (Rhizoctonia solani AG1), and barley powdery mildew (Blumeria graminis f. sp. hordei) were hardly controlled. In addition, the compound showed in vitro antifungal activity against some plant pathogenic fungi including Phytophthora capsici, Alternaria panax, Sclerotinia sclerotiorum, R. solani AG4, and M. grisea. This is the first report on the antifungal activity of phloretin against plant pathogenic fungi.