• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.66-70
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• 2005

Microbiology research must be conducted in a fashion that assures the health and well being of the researcher and the safety of the community. This lecture raises awareness of biosafety issues and discusses how the interaction of the pathogen being studied, the person conducting the research, and the practices being used can be manipulated to assure safety. The characterization of pathogens into Risk Groups, how these relate to Biosafety Levels, and the personal practices and laboratory design criteria associated with each Biosafety Level are explained. The importance of preventing or containing aerosols, limiting opportunities for cross-contamination, and taking a flexible multi-component approach to biosafety are emphasized.

• Mycobiology
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• v.39 no.3
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• pp.143-150
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• 2011

The basidiomycete fungus Cryptococcus neoformans is an important pathogen of immunocompromised people. The ability of the fungus to sense its environment is critical for proliferation and the generation of infectious propagules, as well as for adaptation to the mammalian host during infection. The conserved cAMP/protein kinase A pathway makes an important contribution to sensing, as demonstrated by the phenotypes of mutants with pathway defects. These phenotypes include loss of the ability to mate and to elaborate the key virulence factors capsule and melanin. This review summarizes recent work that reveals new targets of the pathway, new phenotypic consequences of signaling defects, and a more detailed understanding of connections with other aspects of cryptococcal biology including iron regulation, pH sensing, and stress.

• Research in Plant Disease
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• v.25 no.2
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• pp.98-101
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• 2019

Pak choi (or a Bok choy; Brassica rapa subsp. chinensis) is a popular brassicaceous vegetable worldwide. In January 2019, a downy mildew symptom on pak choi was found at a farm located in Yongin, Korea. Based on morphological characteristics and molecular phylogenetic inference, the pathogenic oomycete was identified as Hyaloperonospora brassicae. To our knowledge, this is the first report of downy mildew disease occurring on pak choi in Korea. Considering the increasing demand for this crop, this pathogen would be a potentially new threat to the cultivation of pak choi in Korea.

• Mycobiology
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• v.49 no.2
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• pp.122-132
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• 2021

The reexamination of the fungal genus Botryosphaeria on 12 plant species of 10 families was carried out based on molecular phylogenetic analyses using the regions of translation elongation factor 1-α, β-tubulin, DNA-directed RNA polymerase II subunit, and internal transcribed spacer region of rDNA and morphological characteristics. Japanese isolates were divided into five clades and include Botryosphaeria dothidea, B. qingyuanensis, B. sinensis, and Botryosphaeria spp. Two species, B. qingyuanensis and B. sinensis have been newly added to the Japanese mycoflora, but their host plants are not specified. Botryosphaeria tenuispora isolated from Leucothoe fontanesiana and insect galls on fruits of Aucuba japonica has been proposed as a new species.

• The Korean Journal of Mycology
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• v.51 no.3
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• pp.239-243
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• 2023

The Golovinomyces biocellatus complex is known to consist of powdery mildew from the Golovinomyces genus, associated with host plants from the Lamiaceae family. Recent molecular phylogenetic analyses have resolved the taxonomic composition of this complex, and Golovinomyces biocellatus sensu stricto is considered to be a pathogen of Glechoma species, globally. However, this paper presents a new finding of Golovinomyces salviae on Glechoma longituba, besides its original host species of Salvia. This information was inferred by molecular phylogenetic analyses from the multi-locus nucleotide sequence dataset of intergeneric spacer (IGS), internal transcribed spacer (ITS), large subunit (LSU) of rDNA, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene. Further, the asexual morphology of this fungus is described and illustrated.

• Journal of Plant Biotechnology
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• v.37 no.4
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• pp.414-424
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• 2010

This report describes recent advances in tissue culture, genetic transformation of commercial rose (Rosa hybrida) and in development of new rose cultivars by molecular breeding. Rose is one of major cut-flowers in global horticulture industry. Successful progresses were made in development of new cultivars for pathogen resistant, environmental stress resistant and petal color modification by molecular breeding. New cultivars, however, has not reported yet in korea, although lots of progresses were achieved in each field of conventional breeding, tissue culture and genetic transformation. Cooperation in these research fields will promote screening of useful genes to have specific traits on rose and exploiting of processes to improve in the efficiency of tissue culture and genetic transformation of rose, therefore, we hopefully expect that new rose cultivars by molecular breeding will be released in the near future.

• The Plant Pathology Journal
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• v.38 no.5
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• pp.461-471
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• 2022

Erwinia amylovora is a causative pathogen of fire blight disease, affecting apple, pear, and other rosaceous plants. Currently, management of fire blight relies on cultural and chemical practices, whereas it has been known that few biological resources exhibit disease control efficacy against the fire blight. In the current study, we found that an SFC20201208-M01 fungal isolate exhibits antibacterial activity against E. amylovora TS3128, and the isolate was identified as a Penicillium brasilianum based on the 𝛽-tubulin (BenA) gene sequence. To identify active compounds from the P. brasilianum culture, the culture filtrate was partitioned with ethyl acetate and n-butanol sequentially. From the ethyl acetate layer, we identified two new compounds (compounds 3-4) and two known compounds (compounds 1-2) based on spectroscopic analyses and comparison with literature data. Of these active compounds, penicillic acid (1) exhibited promising antibacterial activity against E. amylovora TS3128 with a minimal inhibitory concentration value of 25 ㎍/ml. When culture filtrate and penicillic acid (125 ㎍/ml) were applied onto Chinese pearleaf crab apple seedlings prior to inoculation of E. amylovora TS3128, the development of fire blight disease was effectively suppressed in the treated plants. Our results provide new insight into the biocontrol potential of P. brasilianum SFC20201208-M01 with an active ingredient to control fire blight.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.13-13
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• 2015

Rice blast fungus, Magnaporthe oryzae, is the most destructive pathogen of rice in the world. This fungus has a biotrophic phase early in infection and switches to a necrotrophic lifestyle after host cell death. During the biotrophic phase, the fungus competes with host for nutrients and oxygen. Continuous uptake of oxygen is essential for successful establishment of blast disease of this pathogen. Here, we report transcriptional responses of the fungus to oxygen limitation. Transcriptome analysis using RNA-Seq identified 1,047 up-regulated genes in response to hypoxia. Those genes were involved in mycelial development, sterol biosynthesis, and metal ion transport based on hierarchical GO terms and well-conserved among three different fungal species. In addition, null mutants of three hypoxia-responsive genes were generated and tested for their roles on fungal development and pathogenicity. The mutants for a sterol regulatory element-binding protein gene, MoSRE1, and C4 methyl sterol oxidase gene, ERG25, exhibited increased sensitivity to hypoxia-mimetic agent, increased conidiation, and delayed invasive growth within host cells, suggesting important roles in fungal development. However, such defects did not cause any significant decrease in disease severity. The other null mutant for alcohol dehydrogenase gene, MoADH1, showed no defect in the hypoxia-mimic condition and fungal development. Taken together, this comprehensive transcriptional profiling in response to a hypoxia condition with experimental validations would provide new insights on fungal development and pathogenicity in plant pathogenic fungi.

• The Plant Pathology Journal
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• v.33 no.2
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• pp.148-162
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• 2017

As a step towards discovering novel pathogenesis-related proteins, we performed a genome scale computational identification and characterization of secreted and transmembrane (TM) proteins, which are mainly responsible for bacteria-host interactions and interactions with other bacteria, in the genomes of six representative Burkholderia species. The species comprised plant pathogens (B. glumae BGR1, B. gladioli BSR3), human pathogens (B. pseudomallei K96243, B. cepacia LO6), and plant-growth promoting endophytes (Burkholderia sp. KJ006, B. phytofirmans PsJN). The proportions of putative classically secreted proteins (CSPs) and TM proteins among the species were relatively high, up to approximately 20%. Lower proportions of putative type 3 non-classically secreted proteins (T3NCSPs) (~10%) and unclassified non-classically secreted proteins (NCSPs) (~5%) were observed. The numbers of TM proteins among the three clusters (plant pathogens, human pathogens, and endophytes) were different, while the distribution of these proteins according to the number of TM domains was conserved in which TM proteins possessing 1, 2, 4, or 12 TM domains were the dominant groups in all species. In addition, we observed conservation in the protein size distribution of the secreted protein groups among the species. There were species-specific differences in the functional characteristics of these proteins in the various groups of CSPs, T3NCSPs, and unclassified NCSPs. Furthermore, we assigned the complete sets of the conserved and unique NCSP candidates of the collected Burkholderia species using sequence similarity searching. This study could provide new insights into the relationship among plant-pathogenic, humanpathogenic, and endophytic bacteria.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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• pp.9-15
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• 2005

Chitin deacetylase (CDA; EC 3.5.1.41) catalyzes the hydrolysis of N-acetamide bonds of chitin, converting it to chitosan. Chitosan has several applications in areas such as biomedicine, food ingredients, cosmetics, pharmaceuticals, and agriculture. In this paper, occurrence, assay and purification protocols, enzymatic characteristics, substrate specificity, and mode of action of microbial CDAs have been described. Several lines of evidence have substantiated the biological roles involved in cell wall formation and plant-pathogen interactions for fungal CDAs. The gene structure of CDAs has been compared with other family 4 carbohydrate esterases which deacetylate a wide variety of acetylated poly/oligo-saccharides. The use of CDAs for the conversion of chitin to chitosan, in contrast to the presently used chemical procedure, offers the possibility of a controlled, non-degradable process, resulting in the production of well-defined chitosan oligomers and polymers. Insect pathogen that can secrete high levels of chitin-metab­olizing enzymes including CDA can be a possible alternative for new pest management tools.