• Research in Plant Disease
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• v.25 no.4
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• pp.220-225
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• 2019

During the year 2018, the symptoms of bunch rot on Shine Muscat (Vitis vinifera L.) were observed in Kimcheon-si, Gyeongbuk province in Korea. The disease appears on the Shine Muscat as a black rot due to prolific fungal sporulation after it has invaded into the Shine Muscat which look completely empty and dryness. Colonies of these fungi are present on the Shine Muscat skin from fruit setting and increase in amount from early season to harvest, while become peak at ripening stage. To isolate the causal agent, small fragments (2 to 3 mm) of decayed tissue from the lesion margin were placed onto potato dextrose agar (PDA) plates. Fungal colonies on PDA produced dense white aerial mycelium and then covered with dark black conidial heads. These heads were large and radiate, and vesicles were globose (2.12-32.0×2.0-3.1 ㎛). Based on morphological and cultural characteristics, this fungus was identified as Aspergillus tubingensis. To confirm its identity, the internal transcribed spacer, β-tubulin, and RNA polymerase II was sequenced for molecular identification. BLAST search indicated 99% identity with A. tubingensis. The pathogenicity test on healthy grape of Shine Muscat produced bunch rot, as the original symptoms. To select effective fungicides for the control of brunch rot, an in vitro antifungal activity of seven fungicides were evaluated against the growth of A. tubingensis. Five fungicides (dipenoconazole, tebuconazole, metconazole, iminoctadine, and captan) exhibited significantly strong suppression of the mycelial growth of A. tubingensis.

• Research in Plant Disease
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• v.15 no.1
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• pp.54-56
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• 2009

Stem rot of perennial statice (Limonium sinuatum) was observed in Un bong, Jeonbuk from 2006 to 2007. Affected plants were randomly distributed in the greenhouses and infection rate was more than 10%. Stem and leaf of statice at soil line were dried and turned brown, initially. As the disease became severe, other stem parts and crowns were turned dark brown and then sunken. The fungal isolates were showed initially white aerial mycelium and turned brown with age. They produced few sclerotia which small, irregularly shaped with pinpoint sized. Mycelia were branched at $90^{\circ}$ angles and multinucleate in one cell. The pathogenicity of causal organism was proved according to Koch's postulates. The causal fungus of stem rot was identified as Rhizoctonia solani based on the cultural and morphological characteristics. This is the first report on stem rot of statice by R. solani in Korea.

• Research in Plant Disease
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• v.21 no.1
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• pp.36-39
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• 2015

In June 2012 and 2013, a destructive stem rot symptoms of Ligularia fischeri occurred sporadically in Hoengseong-gun and Pyeongchang-gun Gangwon-do, Korea. The typical symptom included water-soaking on the main stem, rotting, wilting and blighting, which eventually leads to death of the plant. White mycelial mats were spread over lesions and brown sclerotia were formed on stems and near soil surface. The sclerotia were white to brown, spherical or irregular, 1-3 mm in size on potato dextrose agar (PDA), The optimum temperature range of hyphal growth was $25-30^{\circ}C$ and the hyphal diameter was $4-10{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. The resulting sequence of 695 bp was deposited in GenBank. A BLAST search revealed that sequences of the this isolates showed >99% identity with those of Sclerotium rolfsii. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers ITS rDNA, the fungi were identified as S. rolfsii. A pathogenicity test was carried out to fulfill Koch's postulates. To our knowledge, this is the first report of S. rolfsii on Ligularia fischeri in Korea.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.44-47
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• 2011

A harmful fungus occurred seriously in bed-log of shiitake(Lentinula edodes) in Jangheung-Gun, Korea. The fungus was identified as Bjerkandera adusta by its morphology and ITS(Internal Transcribed Spacer) analysis. The fungus was reported as causal agent of stem-rot of Populus euramericana in Korea, but not reported in bed-log of shiitake until this notification. Thus, studies were made to investigate inside condition of bed-log of shiitake damaged by B. adusta, physiological characteristics of B. adusta and antagonism between these two fungi. First of all, B. adusta is white-rotting fungus like shiitake and wood-rotting condition is similar to that of shiitake. But, there are a lot of small spots in damaged wood tissue under bark which are not seen in case of shiitake. Optimal temperature for mycelial growth of B. adusta is ca. $30^{\circ}C$ while that of shiitake is ca. $25^{\circ}C$. When confrontation cultures were made between these two fungi under $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$, B. adusta has antagonistic ability against shiitake in all the temperatures. From the results of experiments, if the bed-logs of shiitake are exposed to high temperature, there should be mass propagation of B. adusta, and shiitake mycelia will be seriously injured by the fungus. Therefore, to prevent the damage by B. adusta, it is needed to grow the mycelia of shiitake fast in the bed-log, and to avoid exposure of the bed-log to high temperature in summer.

• Research in Plant Disease
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• v.9 no.4
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• pp.217-220
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• 2003

A severe fruit rot of Persimmon (Diospyros kaki cv: Fuyu) was occurred during the storage and transport that infected with blue mold in Sweet Persimmon Experiment Station, Gyeongsangnam-do Agricultural Research and Extension Services, Korea. Fruit surfaces were infected with the fungus first and the colonized fungus formed mycelial mats. From the point of infection, fruits become collapsed and mostly ruptured. The pathogenic fungus from infected fruits was isolated and cultured on PDA. Colony color of the fungus was white at frist than became green on Malt Extract Agar and Czapek Yeast Extract Agar. Conidia were ellipsoid subglobose and 2.6${\sim}$3.8 ${\times}$ 2.4${\sim}$3.8 ${\mu}m$ in size. Stipes were 86${\sim}$320 ${\times}$ 2.8${\sim}$4.3 ${\mu}m$ in size. Rami were 7.5${\sim}$32.6 ${\times}$ 2.6${\sim}$4.2 ${\mu}m$ in size, Ramuli were 12.4${\sim}$14.8 ${\times}$ 3.2${\sim}$3.8 ${\mu}m$ in size, Metulae were 8.9${\sim}$13.6 ${\times}$ 2.8${\sim}$4.6 ${\mu}m$ in size. Phialides were ampulliform, 8.2${\sim}$12.4 ${\times}$ 2.3${\sim}$3.6 ${\mu}m$ in size. Based on the cultural and mycological characteristics and pathogenecity test on host plants, the fungus was identified as s, This is the first report on the blue mold of Persimmon (Diospyros kaki) caused by P. crustosum in Korea.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.253-263
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• 2016

Fungi, such as the wood-rotting Polyporus brumalis, are excellent sources of pharmaceutically interesting natural products such as sesquiterpenoids. In this study, we investigated the biosynthesis of P. brumalis sesquiterpenoids on modified medium. Ten additional species of white rot fungi were inoculated in medium containing nutrients such as $C_6H_{12}O_6$, $C_4H_{12}N_2O_6$, $KH_2PO_4$, $MgSO_4$, and $CaCl_2$ at $28^{\circ}C$ for 25 days. After 10 days of incubation, eudesmane-type sesquiterpenes, ${\beta}$-eudesmane and ${\beta}$-eudesmol, were only synthesized during the growth phase of P. brumalis. Experiments excluding one nutrient at a time were conducted to determine the effects of inorganic nutrients on sesquiterpene biosynthesis. In conclusion, GC-MS analysis showed that biosynthesis of sesquiterpenes was differentially regulated by inorganic nutrients such as $MgSO_4$, $C_4H_{12}N_2O_6$, and $KH_2PO_4$. We found $MgSO_4$ supplementation to be vital for eudesmane-type sesquiterpene biosynthesis in P. brumalis; nitrogen ($C_4H_{12}N_2O_6$) and phosphate ($KH_2PO_4$) inhibited the synthesis of P. brumalis metabolites. Magnesium is a known cofactor of sesquiterpene synthase, which promotes ${\beta}$-eudesmol synthesis. To mechanistically understand eudesmane-type sesquiterpene biosynthesis in P. brumalis, further research into the genes regulating the dynamics of such biosynthesis is warranted.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.365-374
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• 2021

White rot or stem rot caused by Sclerotinia sclerotiorum is one of the most destructive fungal diseases that have become a serious threat to the successful cultivation of oilseed Brassicas. The study was designed with an aim to investigate the association between the pathogenic aggressiveness and pathogenicity determinants of this pathogen specifically in Brassica for the first time. For this, a total of 58 isolates of S. sclerotiorum from different geographical regions were collected and purified. These isolates were inoculated on a Brassica juncea cv. RL-1359 and they exhibited high level of variation in their disease progression. The isolates were grouped and then 24 isolates were selected for the biochemical analysis of pathogenicity determinants. The isolates varied significantly with respect to their total organic acids, oxalic acid production and pectin methyl esterase and polygalacturonase activity. The oxalic acid production corresponded to the disease progression of the isolates; the isolates with higher oxalic acid production were the more aggressive ones and vice-versa. This is, in our knowledge, the first study to establish a correlation between oxalic acid production and pathogenic aggressiveness of S. sclerotiorum on B. juncea. However, the pectinases' enzyme activity did not follow the trend as of disease progression. These suggest an indispensable role of oxalic acid in pathogenicity of the fungus and the potential to be used as biochemical marker for preliminary assessment of pathogenic aggressiveness of various isolates before incorporating them in a breeding program.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.82-85
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• 2009

Endocrine disrupting chemicals (EDCs) disturb animal hormonal system even at very low concentrations, and finally give harmful effects to human through the food web. A white rot fungus Phlebia tremellosa isolated in Korea, was reported to have good degrading activity against the endocrine disrupting phthalates. However, this fungus has very low manganese peroxidase (MnP) activity under various culture conditions while laccase and lignin peroxidase activities were high. We have isolated an MnP cDNA from Trametes versicolor which was involved in the degradation of EDCs, and constructed an MnP expression vector to use in the genetic transformation of P. tremellosa in order to get higher MnP producing strains. Many transformants had integrated expression vector in their chromosomal DNAs, and showed increased MnP activity. One of two transformants showed increased degradation of 4 EDCs (70${\sim}$88%) than the wild type (30${\sim}$45% degradation rates), and showed twice better removal of estrogenic activities generated by the EDCs than the wild type.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.199-202
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• 2008

A white rot fungus Irpex lacteus produced lignin degrading enzymes, which showed degrading activity against various recalcitrant compounds. However, laccase, one of the lignin degrading enzymes, was too low to be assayed by spectrophotometry using o-tolidine as the chromogenic substrate in this fungus under various culture conditions. A laccase expression vector was constructed using a cDNA from Phlebia tremellosa with the constitutively expressed promoter of glyceraldehydes-3-phosphate dehydrogenase gene, and introduced into I. lacteus by the restriction enzyme mediated integration transformation through the protoplast-$CaCl_2$ procedure. Two transformants showed highly increased laccase activities at the early growth phase in the minimal liquid medium, and they not only degraded bisphenol A, a notorious endocrine disrupting chemical, but also removed the estrogenic activity effectively.

• Clean Technology
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• v.10 no.3
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• pp.131-137
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• 2004

Due to the low biodegradability of dyes, conventional biological wastewater treatment systems are inefficient in treating textile wastewater. In this study, white rot fungus, Trametes versicolor KCTC 16781, were investigated for the decolorization of Reactive black 5 solutions. This fungus was able to degrade the dye solutions by the ligninolytic enzymes (laccase and MnP) produced. The enzyme activity remained constant until the end of reaction. The combined process of biological treatment and ceramic membrane showed better efficiency for decolorization and TOC removal than each single process.