• 한국식물병리학회지
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• 제13권2호
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• pp.132-137
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• 1997

Phytotoxicity of the culture filtrate and culture conditions for the production of the phytotoxin by Exserohilum monoceras 92-044 were examined. The necrotic lesions were developed on the leaves of Echinochloa crus-galli within 48 hrs after inoculation of the culture filtrate, and the leaves were completely blighted within 5∼7 days. Maximum toxicity was found in the culture broth containing 20% V-8 juice. Phytotoxin accumulation and fungal growth reached their highest peak at around 11 days. Typical symptom appeared on the leaf of E. crus-galli within 48 hrs. Only a weak chlorosis appeared on rice, Arundinella hirta (THUNB) and henry crabgrass (Digitaria sanguinalis SCOP.), but no further symptom developed.

• 한국균학회지
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• 제46권4호
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• pp.437-446
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• 2018

We investigated the biodiversity of endophytic fungi in Pinus densiflora and Junipreus rigida from Mt. Baekryeonsan and Mt. Johangsan in Korea. In total, 59 isolates were discovered from 26 host plants and identified using sequences from the rDNA internal transcribed spacer (ITS) region. Twenty taxa of endophytic fungi were identified in this study; 62% of isolates belonged to Leotiomycetes, 34% belonged to Sordariomyetes, and 4% belonged to Agaricomycetes. Results confirmed three previously unreported endophytic fungi in Korea: Phanerochaete concrescens, Creosphaeria sassafras, and Scopuloides rimosa. Community analysis showed that the fungal diversity patterns of the samples from Mt Baekryeonsan and Mt. Johangsan are similar to those from previous studies and varied depending upon host and locality.

• 한국균학회지
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• 제50권2호
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• pp.137-141
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• 2022

In Korea, powdery mildew has been observed on Quercus rubra, commonly called the northern red oak tree. Based on its morphological and molecular phylogenetic analyses, the fungal agent was identified as Erysiphe quercicola, but it was distinct from the other four Erysiphe species, specialized to Quercus species. This is the first confirmed report on the identity of powdery mildew found on Q. rubra in Korea. This finding can help understand the host expansion of E. quercicola and the biodiversity of powdery mildew on Quercus species.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2014년도 추계학술대회 및 정기총회
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• pp.11-11
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• 2014

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. M. oryzae is a causal agent of rice blast disease, which destroys 10 to 30% of the rice crop annually. Since the rice is the staple food for more than half of human population, the disease is a major threat to global food security. In addition to the socioeconomic impact of the disease it causes, the fungus is genetically tractable and can undergo well-defined morphological transitions including asexual spore production and appressorium (a specialized infection structure) formation in vitro, making it a model to study fungal development and pathogenicity. For functional and comparative analysis of histone modifications, a web-based database (dbHiMo) was constructed to archive and analyze histone modifying enzymes from eukaryotic species whose genome sequences are available. Histone modifying enzymes were identified applying a search pipeline built upon profile hidden Markov model (HMM) to proteomes. The database incorporates 22,169 histone-modifying enzymes identified from 342 species including 214 fungal, 33 plants, and 77 metazoan species. The dbHiMo provides users with web-based personalized data browsing and analysis tools, supporting comparative and evolutionary genomics. Based on the database entries, functional analysis of genes encoding histone acetyltransferases and histone demethylases is under way. 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 will be 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.

• 한국균학회지
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• 제43권1호
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• pp.13-19
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• 2015

낙동강 지류의 하천에 자생하는 5종류의 수생식물인 마름, 물억새, 미나리, 부들, 및 줄을 채집하였다. 수생식물의 뿌리에서 분리된 34균주의 내생균류는 ITS영역 염기 서열을 분석하였다. 분리된 모든 내생균류들에 대하여 다양성 지수와 계통분석을 수행하였다. 내생균류는 17속으로서, Acremonium속, Alternaria속, Aspergillus속, Cladosporium속, Emericellopsis속, Fusarium속, Galactomyces속, Leptosphaeria속, Microsphaeropsis속, Penicillium속, Peyronellaea속, Phoma속, Pseudeurotium속, Rhizomucor속, Talaromyces속, Trematosphaeria속, Zalerion속 등이 분리되었다. 5종류의 수생식물에서 Alternaria, Talaromyces속의 균류들이 비교적 많이 분포하고 있었다. 본 연구는 낙동강 지류의 하천 습지에 자생하는 수생식물 군락에서 공생하는 내생균류의 다양성에 대한 연구이다.

• The Plant Pathology Journal
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• 제27권3호
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• pp.225-231
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• 2011

Previously, we identified the 20S proteasome ${\alpha}$-subunit of Magnaporthe oryzae (M. oryzae) induced during appressorium formation, and detected an increase in multiple protein ubiquitination during the early appressorium formation process (Kim et al., 2004). In this study, we further attempted to determine whether the proteasome is involved in the appressorium formation of M. oryzae both in vitro and in planta, using proteasome inhibitors. A significant increase in 20S proteasome during fungal germination and appressorium formation was observed using Western blot analysis with 20S proteasome antibody, demonstrating that proteasome-mediated protein degradation was involved in appressorium formation. Pharmacological analysis using proteasome inhibitors, MG-132, proteasome inhibitor I (PI) and proteasome inhibitor II (PII) revealed that germination and appressorium formation were delayed for 4 to 6 h on rice leaf wax-coated plates. Similarly, the treatment of proteasome inhibitors with fungal conidia on the rice leaf surface delayed appressorium formation and host infection processes as well. Additionally, fungal pathogenicity was strongly reduced at 4 days' postfungal infection. These data indicated that the fungal 20S proteasome might be involved in the pathogenicity of M. oryzae by the suppression of germination and appressorium formation.

• The Plant Pathology Journal
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• 제37권6호
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• pp.607-618
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• 2021

The pepper anthracnose fungus, Colletotrichum scovillei, causes severe losses of pepper fruit production in the tropical and temperate zones. RAC1 is a highly conserved small GTP-binding protein in the Rho GT-Pase family. This protein has been demonstrated to play a role in fungal development, and pathogenicity in several plant pathogenic fungi. However, the functional roles of RAC1 are not characterized in C. scovillei causing anthracnose on pepper fruits. Here, we generated a deletion mutant (𝜟Csrac1) via homologous recombination to investigate the functional roles of CsRAC1. The 𝜟Csrac1 showed pleiotropic defects in fungal growth and developments, including vegetative growth, conidiogenesis, conidial germination and appressorium formation, compared to wild-type. Although 𝜟Csrac1 was able to develop appressoria, it failed to differentiate appressorium pegs. However, 𝜟Csrac1 still caused anthracnose disease with significantly reduced rate on wounded pepper fruits. Further analyses revealed that 𝜟Csrac1 was defective in tolerance to oxidative stress and suppression of host-defense genes. Taken together, our results suggest that CsRAC1 plays essential roles in fungal development and pathogenicity in C. scovilleipepper fruit pathosystem.

• Tuberculosis and Respiratory Diseases
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• 제74권6호
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• pp.269-273
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• 2013

Mucormycosis is a rare fungal disease that holds a fatal opportunistic fungal infection in diabetes mellitus, hematological malignancy, and immunocompromised host. Isolated pulmonary mucormycosis is extremely rare. Optimal therapy is a combined medical-surgical approach and a management of the patient's underlying disease. Herein, we report a case-study of isolated pulmonary mucormycosis which was being presented as multiple lung nodules in a patient with no underlying risk factors. Considering that the patient had poor pulmonary functions, we treated him with only antifungal agent rather than a combined medical-surgical approach. After treatment with antifungal agent for six months, the nodules of pulmonary mucormycosis were improved with the prominent reductions of size on the computed tomography.

• Journal of Microbiology and Biotechnology
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• 제25권7호
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• pp.988-998
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• 2015

The filamentous fungus Aspergillus oryzae is a well-known expression host used to express homologous and heterologous proteins in a number of industrial applications. To facilitate higher yields of proteins of interest, we constructed the pAsOP vector to express heterologous proteins in A. oryzae. pAsOP carries a selectable marker, pyrG, derived from Aspergillus nidulans, and a strong promoter and a terminator of the amyB gene derived from A. oryzae. pAsOP transformed A. oryzae efficiently via the PEG-CaCl₂-mediated transformation method. As proof of concept, green fluorescent protein (GFP) was successfully expressed in A. oryzae transformed by pAsOP-GFP. Additionally, we identified a novel fungal α-amylase (PcAmy) gene from Penicillium sp. and cloned the gene into the vector. After transformation by pAsOPPcAmy, the α-amylase PcAmy from Penicillium sp. was successfully expressed in a heterologous host system for the first time. The α-amylase activity in the A. oryzae transformant was increased by 62.3% compared with the untransformed A. oryzae control. The PcAmy protein produced in the system had an optimum pH of 5.0 and optimum temperature of 30^oC. As a cold-adapted enzyme, PcAmy shows potential value in industrial applications because of its high catalytic activity at low temperature. Furthermore, the expression vector reported in this study provides promising utility for further scientific research and biotechnological applications.

• 한국균학회지
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• 제22권2호
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• pp.172-183
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• 1994

접합내생균근 균(AMF)이 있는 토양을 이용하여 여러 종류의 비료를 주면서 식물을 재배하여, AMF포자 증식에 대하여 관찰하였다. 식물뿌리에서 AM화된 뿌리는 여러가지 형태가 현미경 관찰을 통하여 확인되었으며, 정상적인 Vesicles, Arbuscles 및 sporulation 과정도 관찰되었으며, 꽃송이와 같은 특수한 형태도 관찰되었다. 포자증식에 있어서의 80일간의 관찰과 뿌리염색을 통한 뿌리감염도의 관찰결과, 40일 주기로 포자의 생산에 증감이 주기적으로 일어나는 것을 관찰하였다. 비료를 첨가한 토양에서 수수, 파, 고추 및 차풀의 순으로 포자 증식에 좋은식물로 나타났으며, 그 포자 증식이 조건에 따라 다양하게 나타났다. 비료의 첨가에서는 인산이 없는 비료에서 포자증식이 크게 일어났으며, 21-17-17 비료에서는 포자증식 적었다. 식물별로 본다면, 수수, 고추, 파등의 순으로 포자증식이 많이 되었다.