• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.149-154
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• 2015

BACKGROUND: Yeast isolates associated with the leaves, stems, and flowers of the tiger lily needed to be identified using isolation methods that have previously been used effectively in yeast biotechnology. A culture-based approach was necessary for the isolation of many yeast strains associated with tiger lily. METHODS AND RESULTS: In this study, the homogenized leaves, stems, and flowers of tiger lily were spreaded onto GPY medium containing chloramphenicol, streptomycin, Triton X-100, and L-sorbose. A total of 82 yeast strains from the leaves, 94 and 97 yeast strains from the stems and flowers were isolated, respectively. Yeast isolates were identified by phylogenetic analysis based on internal transcribed spacer region sequencing. The yeast species isolated from the leaves comprised of 31 isolates of the genus Pseudozyma, 28 of Aureobasidium pullulans, and 11 of the genus Cryptococcus. Those isolated from the stems comprised of 40 of A. pullulans and 11 of Cryptococcus, and 95 of A. pullulans While, 1 isolate each of the genera Rhodotorula and Metschnikowia were isolated from the flowers. CONCLUSION: We identified site-specific yeast communities associated with tiger lily. These yeast isolates may have high potential for application in the field of biotechnology.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.394-401
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• 2013

Trichoderma harzianum is one of rhizosphere fungus usually lives near the plant root regions in the soil. T. harzianum plays an important role in plant growth promotion and increases disease resistance against various plant pathogens on crops. In this study, the strain T. harzianum MPA167 was isolated from the barley rhizosphere soil in Suwon, Korea. Among 183 isolates, the strain T. harzianum MPA167 was selected as promising strain in which based on hyperparasitical activity against Phytophthora capsici and estimated disease control activity against P. capsici in the greenhouse conditions. The strain T. harzianum MPA167 was identified using 23s rDNA internal transcribed spacer(ITS) region sequences. MPA167 treatment ($1{\times}10^6$ spores/ml) showed greater disease suppression against Phytophthora blight of red-pepper caused by P. capsici in greenhouse compared with the water-treated control. Volatiles derived from T. harzianum MPA167 elicit growth promotion of tobacco and Arabidopsis seedlings in I-plate assay. In addition, T. harzianum MPA167 strain was also found to be effective for the growth promotion and induction of systemic resistance on red-papper plant. These results suggest that MPA167 might be used as one of the potential biocontrol agents.

• Research in Plant Disease
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• v.20 no.1
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• pp.50-53
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• 2014

Rhizopus soft rot of lily (Lilium longiflorum) caused by Rhizopus oryzae was observed in the experimental field in Taean Lily Experiment Station in Korea, 2012. The typical symptoms were water-soaked lesions on bottom stem and leaf rot. The lesion rapidly expanded and the plant was softened totally. The fungus grew vigorously at an optimum temperature ($25^{\circ}C$) and brownish colony and black sporangia were formed on potato dextrose agar medium. Sporangiophores formed on end of sporangia were sub-globose, brownish and $6-10{\mu}m$ in size. Sporangia were globose, blackish and $87-116{\mu}m$ in size. Sporangiospores were irregularly oval and sub-globose, brownish $4-8{\mu}m$ in size. On the basis of mycological characteristics, analyzing sequences of internal transcribed spacer region of ribosomal DNA, and pathogenicity test on host plants, the causal fungus was identified as R. oryzae. This is the first report of Rhizopus soft rot on lily caused by R. oryzae in Korea.

• Journal of Life Science
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• v.22 no.7
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• pp.970-980
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• 2012

Native halophytes, such as Suaeda maritima, Limonium tetragonum, S. japonica, Zoysia sinica, and Phragmites australis were collected from the Muan salt marsh. Ninety endophytic fungi were isolated from the roots of the collected halophytes. Molecular insights inferred by internal transcribed spacer containing ITS1, 5.8s, and the ITS2 region showed that all the fungal strains belong to ten orders, i.e., Capnodiales (4.44%), Cystofilobasidiales (1.11%), Dothideales (3.33%), Eurotiales (53.33%), Glomerellales (3.33%), Hypocreales (8.89%), Mucorales (1.11%), Pleosporales (15.56%), Sordariales (1.11%), and Trichosphaeriales (1.11%). The rest (6.67%) of all fungal isolates were not identified. Ninety fungal strains were confirmed at the genus level, containing Acremonium, Alternaria, Aspergillus, Aureobasidium, Cephalosporium, Chaetomium, Cladosporium, Colletotrichum, Cryptococcus, Didymella, Dothideomycete, Emericellopsis, Epicoccum, Eupenicillium, Fusarium, Gibberella, Gongronella, Macrophoma, Microsphaeropsis, Nigrospora, Paecilomyces, Paraconiothyrium, Penicillium, Phaeomyces, Phoma, Pleosporales, Purpureocillium, and Talaromyces. Of all the endophytic fungi identified from the various halophytes, Aspergillus and Penicillium of Eurotiales had the highest abundance.

• Research in Plant Disease
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• v.18 no.4
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• pp.331-337
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• 2012

Citrus melanose is one of important disease in citrus cultivation, reducing quality of citrus fruits and resulting in economic loss. Like other diseases in citrus, melanose was mainly protected by chemical fungicide in the field. Recently, alternative method of disease control is highly required due to the side effect of the chemicals. In this study four rhizobacterial strains TRH423-3, MRL408-3, THJ609-3, and TRH415-2 are selected by dual-culture testing its antifungal activity against Diaporthe citri causing citrus melanose. To investigate the protection efficacy of the selected rhizobacterial strains to citrus melanose, the bacteria were pre-treated on citrus leaves following inoculation with melanose pathogen. Pre-treatment with all selected rhizobacterial strains showed disease suppression in which the levels of protection rates were different by the rhizobacterial strains. Additional treatment with the rhizobacterial strains after the pathogen inoculation enhanced protection rates in all cases. The strain MRL408-3 and TRH423-3 were identified as Burkholderia gladioli, TRH415-2 as Pseudomons fluorescens and THJ609-3 as Pseudomonas pudia as a result of analyzing the internal transcript spaces of the rhizobacterial strains rDNA. The selected rhizobacterial strains may be valuable as biological control agents in the environment-friendly citrus farm in which chemical application is limited.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.6
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• pp.1002-1011
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• 2020

Objective: This study was conducted to determine the composition and diversity of the fungal flora at various control points in cheese ripening rooms of 10 dairy farms from six different provinces in the Republic of Korea. Methods: Floor, wall, cheese board, room air, cheese rind and core were sampled from cheese ripening rooms of ten different dairy farms. The molds were enumerated using YM petrifilm, while isolation was done on yeast extract glucose chloramphenicol agar plates. Morphologically distinct isolates were identified using sequencing of internal transcribed spacer region. Results: The fungal counts in 8 out of 10 dairy farms were out of acceptable range, as per hazard analysis critical control point regulation. A total of 986 fungal isolates identified and assigned to the phyla Ascomycota (14 genera) and Basidiomycota (3 genera). Of these Penicillium, Aspergillus, and Cladosporium were the most diverse and predominant. The cheese ripening rooms was overrepresented in 9 farms by Penicillium (76%), while Aspergillus in a single farm. Among 39 species, the prominent members were Penicillium commune, P. oxalicum, P. echinulatum, and Aspergillus versicolor. Most of the mold species detected on surfaces were the same found in the indoor air of cheese ripening rooms. Conclusion: The environment of cheese ripening rooms persuades a favourable niche for mold growth. The fungal diversity in the dairy farms were greatly influenced by several factors (exterior atmosphere, working personnel etc.,) and their proportion varied from one to another. Proper management of hygienic and production practices and air filtration system would be effective to eradicate contamination in cheese processing industries.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2119-2128
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• 2017

Citrinin (CIT) is a toxic secondary metabolite produced by fungi belonging to the Penicillium, Aspergillus, and Monascus spp. This toxin has been detected in many agricultural products. In this study, a strain Y3 with the ability to eliminate CIT was screened and identified as Cryptococcus podzolicus, based on the sequence analysis of the internal transcribed spacer region. Neither uptake of CIT by cells nor adsorption by cell wall was involved in CIT elimination by Cryptococcus podzolicus Y3. The extracellular metabolites of Cryptococcus podzolicus Y3 stimulated by CIT or not showed no degradation for CIT. It indicated that CIT elimination was attributed to the degradation of intracellular enzyme(s). The degradation of CIT by C. podzolicus Y3 was dependent on the type of media, yeast concentration, temperature, pH, and initial concentration of CIT. Most of the CIT was degraded by C. podzolicus Y3 in NYDB medium at 42 h but not in PDB medium. The degradation rate of CIT was the highest (94%) when the concentration of C. podzolicus Y3 was $1{\times}10^8cells/ml$. The quantity of CIT degradation was highest at $28^{\circ}C$, and there was no degradation observed at 3$5^{\circ}C$. The study also showed that acidic condition (pH 4.0) was the most favorable for CIT degradation by C. podzolicus Y3. The degradation rate of CIT increased to 98% as the concentration of CIT was increased to $20{\mu}g/ml$. The toxicity of CIT degradation product(s) toward HEK293 was much lower than that of CIT.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.12
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• pp.815-824
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• 2016

The fuel assembly for pressurized water reactor (PWR) consists of fuel rod bundle, spacer grid and bottom/top end fittings. The cooling water in high pressure and temperature is introduced in lower plenum of reactor core and directed to upper plenum through the subchannel which is formed between the fuel rods. The main thermal-hydraulic performance parameters for the PWR fuel are pressure drop and critical heat flux in normal operating condition, and quenching time in accident condition. The Korea Atomic Energy Research Institute (KAERI) has been developing an advanced PWR fuel, dual-cooled annular fuel and accident tolerant fuel for the enhancement of fuel performance and the localization. For the key thermal-hydraulic technology development of PWR fuel, the KAERI LWR fuel team has conducted the experiments for pressure drop, turbulent flow mixing and heat transfer, critical heat flux(CHF) and quenching. The computational fluid dynamics (CFD) analysis was also performed to predict flow and heat transfer in fuel assembly including the spent fuel assembly in dry cask for interim repository. In addition, the research cooperation with university and nuclear fuel company was also carried out to develop a basic thermal-hydraulic technology and the commercialization.

• Journal of Plant Biotechnology
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• v.44 no.1
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• pp.56-60
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• 2017

This study investigated the in vitro symbiotic seed germination of the achlorophyllous orchid, Gastrodia elata, using a new Mycena species. A leaf-disc ($2{\times}2cm$) of Quercus accutissima was inoculated with either of the two fungal species, NIFOS101 (NCBI accession number KY449288) or KFRI1212 (HQ662845), following which it was placed on water agar medium, prior to sowing seeds of G. elata. After 20 days of symbiotic culture, NIFOS101 and KFRI1212 germinated 94% and 70% of G. elata seeds, respectively, although the initiation of protocorm development was induced much earlier by KFRI 1212 than by NIFOS101. Furthermore, the NIFOS101 mycelia grew much faster than KFRI 1212 at all temperatures tested. A phylogenetic analysis using the internal transcribed spacer (ITS) sequences showed that NIFOS101 belonged to a clade with M. purpureofusca, which completely differed from the clade with KFRI1212. This study not only identified a new fungal species, NIFOS101, which improved the rate of symbiotic seed germination up to 94% as compared to KFRI1212 (70%), but also revealed that G. elata required a broad taxonomic range of fungi for its symbiotic germination.

• The Korean Journal of Mycology
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• v.43 no.3
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• pp.200-205
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• 2015

Perilla frutescens var. japonica Hara was collected from farmland in Seongju-gun. Fifteen endophytic fungal strains with different colony morphologies were isolated from roots of P. frutescens. Waito-c rice seedlings were treated with the concentrated culture filtrates (CF) of endophytic fungi for observation of their plant growth-promoting activities. In the results, the CF of Y2H001 fungal strain promoted the growth of the waito-c rice seedlings. The phylogenetic tree of Y2H001 strain was analyzed by the combined sequences of the partial internal transcribed spacer region (ITS) and partial betatubulin gene. Molecular and morphological studies identified the Y2H001 strain as belonging to Aspergillus flavus. In gas chromatography mass spectrometry (GC/MS) analysis of the CF of Y2H001 strain, gibberellic acid (GA) was detected and quantified. Therefore, we describe Y2H001 strain as a new $GA_3$-producing A. flavus based on morphological, molecular characteristics and analysis of secondary metabolite.