• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.19-19
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• 2018

Fungal pathogens have huge impact on health and economic wellbeing of human by causing life-threatening mycoses in immune-compromised patients or by destroying crop plants. A key determinant of fungal pathogenesis is their ability to undergo developmental change in response to host or environmental factors. Genetic pathways that regulate such morphological transitions and adaptation are therefore extensively studied during the last few decades. Given that epigenetic as well as genetic components play pivotal roles in development of plants and mammals, contribution of microbial epigenetic counterparts to this morphogenetic process is intriguing yet nearly unappreciated question to date. To bridge this gap in our knowledge, we set out to investigate histone modifications among epigenetic mechanisms that possibly regulate fungal adaptation and processes involved in pathogenesis of a model plant pathogenic fungus, Magnaporthe oryzae. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed first to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Based on the database entries, we carried out functional analysis of genes encoding histone modifying enzymes. Here I provide examples of such analyses that show how histone acetylation and methylation is implicated in regulating important aspects of fungal pathogenesis. Current analysis of histone modifying enzymes is followed by ChIP-seq and RNA-seq experiments to pinpoint the genes that are controlled by particular histone modifications. We anticipate that our work will provide not only the significant advances in our understanding of epigenetic mechanisms operating in microbial eukaryotes but also basis to expand our perspective on regulation of development in fungal pathogens.

• The Plant Pathology Journal
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• 제39권5호
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• pp.513-521
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• 2023

Seed-borne diseases reduce not only the seed germination and seedling growth but also seed quality, resulting in the significant yield loss in crop production. Plant seed harbors diverse microbes termed endophytes other than pathogens inside it. However, their roles and application to agricultures were rarely understood and explored to date. Recently, we had isolated from soybean seeds culturable endophytes exhibiting in-vitro antagonistic activities against common bacterial and fungal seed-borne pathogens. In this study, we evaluated effects of seed treatment with endophytes on plant growth and protection against the common seed-borne pathogens: four fungal pathogens (Cercospora sojina, C. kikuchii, Septoria glycines, Diaporthe eres) and two bacterial pathogens (Xanthomonas axonopodis pv. glycines, Pseudomonas syringae pv. tabaci). Our experiments showed that treatment of soybean seeds with seed endophytes clearly offer protection against seed-borne pathogens. We also found that some of the endophytes promote plant growth in addition to the disease suppression. Taken together, our results demonstrate agricultural potential of seed endophytes in crop protection.

• Journal of Microbiology and Biotechnology
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• 제20권5호
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• pp.904-907
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• 2010

The vibration of fungal cultures was evaluated to determine its potential effect on the dispersal of airborne fungal microorganisms suspected of being pathogens. An artificial vibration system, which simulates the actual environmental vibration of fungal structures, was designed and constructed for this purpose. Experiments featured the use of low-frequency vibrations similar to those induced by earthquakes. Within the range of conditions tested, the vibration of fungal cultures was found to affect the airflow-driven generation of bioaerosols.

• 한국미생물·생명공학회지
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• 제45권4호
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• pp.358-364
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• 2017

Asymmetric PCR preferentially amplifies one DNA strand for use in DNA hybridization studies. Linear-After-The-Exponential-PCR (LATE-PCR) is an advanced asymmetric PCR method which uses innovatively designed primers at different concentrations. This study aimed to optimise LATE-PCR parameters to produce single-stranded DNA of Candida spp. and Aspergillus spp. for detection via probe hybridisation. The internal transcribed spacer (ITS) region was used to design limiting primer and excess primer for LATE-PCR. Primer annealing and melting temperature, difference of melting temperature between limiting and excess primer and concentration of primers were optimized. In order to confirm the presence of single-stranded DNA, the LATE-PCR product was hybridised with digoxigenin labeled complementary oligonucleotide probe specific for each fungal genus and detected using anti-digoxigenin antibody by dot blotting. Important parameters that determine the production of single-stranded DNA in a LATE-PCR reaction are difference of melting temperature between the limiting and excess primer of at least $5^{\circ}C$ and primer concentration ratio of excess primer to limiting primer at 20:1. LATE-PCR products of Candida albicans, Candida parapsilosis, Candida tropicalis and Aspergillus terreus at up to 1:100 dilution and after 1 h hybridization time, successfully hybridised to respective oligonucleotide probes with no cross reactivity observed between each fungal genus probe and non-target products. For Aspergillus fumigatus, LATE-PCR products were detected at 1:10 dilution and after overnight hybridisation. These results indicate high detection sensitivity for single-stranded DNA produced by LATE-PCR. In conclusion, this advancement of PCR may be utilised to detect fungal pathogens which can aid the diagnosis of invasive fungal disease.

• 한국토양비료학회지
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• 제45권4호
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• pp.622-627
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• 2012

The processes to determine the composition, dynamics, and activity of infection mechanisms by the rhizosphere microflora have attracted the interest of scientists from multiple disciplines although considerable progress of the infection pathways and plant-pathogen interactions by soil borne fungal pathogens have been made. Soilborne pathogens are confined within a three-dimensional matrix of mineral soil particles, pores, organic matter in various stages of decomposition and a biological component. Among the physical and chemical properties of soils soil texture and matric water potential may be the two most important factors that determine spread exudates by soil borne fungal pathogens, based on the size of the soil pores. Pathogenic invasion of plant roots involves complex molecular mechanisms which occur in the diffuse interface between the root and the soil created by root exudates. The initial infection by soilborne pathogens can be caused by enzymes which breakdown cell wall layers to penetrate the plant cell wall for the fungus. However, the fate and mobility of the exudates are less well understood. Therefore, it needs to develop methods to control disease caused by enzymes produced by the soilborne pathogens by verifying many other possible pathways and mechanisms of infection processes occurring in soils.

• 식물병연구
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• 제19권3호
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• pp.177-182
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• 2013

Resvestrol has been known to inhibit bacterial and fungal growth in vitro, and can be accumulated in plant to concentrations necessary to inhibit microbial pathogens. Hence, stilbene synthase gene has been used to transform to synthesize resveratrol in heterologous plant species to enhance resistance against pathogens. In the present study, we investigated the antimicrobial activities of resveratrol and piceid to bacterial and fungal pathogens, which causing severe damages to rice plants. In addition, disease resistance was compared between transgenic rice varieties, Iksan 515 and Iksan 526 transformed with stlibene synthase gene and non-transgenic rice varieties, Dongjin and Nampyeong. Minimum inhibitory concentration of resveratrol for Burkolderia glumae was 437.5 ${\mu}M$, and the mycelial growth of Biplaris oryzae was slightly inhibited at concentration of 10 ${\mu}M$. However, other bacterial and fungal pathogens are not inhibited by resveratrol and piceid. The expression of the stilbene synthase gene in Iksan 515 and Iksan 526 did not significantly enhanced resistance against bacterial grain rot, bacterial leaf blight, sheath blight, and leaf blight. This study is the first report on the effect of resveratrol and piceid against pathogens of rice plant, and changes of disease resistance of transgenic rice plants transformed with stilbene synthase gene.

• Current Research on Agriculture and Life Sciences
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• 제3권
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• pp.112-119
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• 1985

관상식물(觀賞植物)에 병해조사(病害調査) 일환(一環)으로 대구(大邱)와 근교(近郊)의 온실(溫室) 등(等)에 재식(栽植)되어 있는 19과(科) 34속(屬) 34종(種)의 식물(植物)에 대(對)하여 진균(眞菌)에 이병(罹病)된 식물(植物)을 조사(調査)한 결과(結果), Glomerella 속균(屬菌) 등(等) 16속(屬) 병원진균(病原眞菌)에 의(依)하여 32속(屬) 32종(種)의 식물(植物)에서 37종(種)의 병(病)이 발생(發生)하고 있었다. 이들 중 우리나라에서 이제까지 보고(報告)되지 않은 미기록병해(未記錄病害)는 Glomerella속균(屬菌), Colletotrichum속균(屬菌), Ceratocystis속균(屬菌), Pestalotia속균(屬菌), Gloeosporium속균(屬菌), Macrophoma속균(屬菌), Sphaceloma속균(屬菌), Botrytis속균(屬菌), Alternaria속균(屬菌), Phyllosticta속균(屬菌), 및 Phomopsis속균(屬菌) 등(等)에 의(依)하여 19속(屬) 19종(種)의 관상식물(觀賞植物)에 22종(種)의 병(病)이 발생(發生)하고 있음을 확인(確認)하였다.

• Current Research on Agriculture and Life Sciences
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• 제3권
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• pp.120-128
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• 1985

대구(大邱)를 중심(中心)으로 한 5개(個) 지역(地域)에 재식(裁植)되어 있는 23과(科) 28속(屬) 32종(種)의 관상식물(觀賞植物)에 대(對)하여 진균(眞菌)에 이병(罹病)된 식물(植物)을 조사(調査)한 결과(結果) Uncinula 속균(屬菌) 등(等) 21속(屬)의 병원진균(病原眞菌)에 의(依)하여 26속(屬) 30(種)의 식물(植物)에서 45종(種)의 병(病)이 발생(發生)하고 있었다. 이들 중(中) 우리나라에서 이제까지 보고(報告)되지 않은 미기록병해(未記錄病害)는 Uncinula속균(屬菌), Phyllosticta속균(屬菌), Discosia속균(屬菌), Macrophoma속균(屬菌), Colletotrichum속균(屬菌), Pestalotia속균(屬菌), Phomopsis속균(屬菌), Gloeosporium속균(屬菌), Alternaria속균(屬菌), Fusicoccum속균(屬菌) 및 Sphaceloma속균(屬菌) 등(等)에 의(依)하여 15속(屬) 16종(種)의 식물(植物)에 22종(種)의 병(病)이 발생(發生)하고 있었다.

• The Plant Pathology Journal
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• 제16권5호
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• pp.286-289
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• 2000

Mechanol extracts of three cold-tolerant eucalyptus trees-Eucalyptus darlympleana, E. gunnii and E. unigera were screened for antimicrobial activity against twenty two phyto-pathogenic fungi and six food-borne bacterial pathogens. E. unigera showed the antagonistic activity against all the tested pathogens. Among the tested fungal pathogens, Pythium species were highly sensitive to the leaf extracts. Especially, P. vanterpoolii, a causal agent of leaf blight in creeping bentgrass (Agrostis palustris), was completely inhibited by the extracts. The eucalyptus extracts were also effective in inhibiting the fungal growth of Botrytis cinerea and Phomopsis sp. isolated from the lesions of kiwifruit soft rot during post-harvest storage. Escherichia coli O-157 was less sensitive to the inhibition than the other bacterial pathogens tested. It was likely that Gram positive bacteria-Bacillus subtilis and Streptococcus mutans were more sensitive to the eucalyptus extracts than Gram negative bacteria-Escherichia coli, Salmonella enteritidis and Pseudomonas aeruginosa. Our findings suggest that the cold-tolerant eucalyptus species have antimicrobial properties that can serve the development of novel fungitoxic agents or food preservatives.

• The Plant Pathology Journal
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• 제34권4호
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• pp.327-334
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• 2018

Northern corn leaf spot and southern corn leaf blight caused by Cochliobolus carbonum (anamorph, Bipolaris zeicola) and Cochliobolus heterostrophus (anamorph, Bipolaris maydis), respectively, are common maize diseases in Korea. Accurate detection of plant pathogens is necessary for effective disease management. Based on the polyketide synthase gene (PKS) of Cochliobolus carbonum and the nonribosomal peptide synthetase gene (NRPS) of Cochliobolus heterostrophus, primer pairs were designed for PCR to simultaneously detect the two fungal pathogens and were specific and sensitive enough to be used for duplex PCR analysis. This duplex PCR-based method was found to be effective for diagnosing simultaneous infections from the two Cochliobolus species that display similar morphological and mycological characteristics. With this method, it is possible to prevent infections in maize by detecting infected seeds or maize and discarding them. Besides saving time and effort, early diagnosis can help to prevent infections, establish comprehensive management systems, and secure healthy seeds.