• The Plant Pathology Journal
• /
• v.24 no.2
• /
• pp.118-124
• /
• 2008

Skin sooty dapple disease, a fungal disease that lowers Asian pear fruit quality, has emerged recently in Korea but has not yet been thoroughly characterized. This disease affects the surface of fruit, leaves, and young shoots of the Asian pear, typically appearing as a dark or pale black dapple on the fruit surface. The disease initiates on the fruit with small circular lesions that become bigger, eventually spreading to form large circular or indefinite lesions. Sparse dark or flourishing white-greyish aerial mycelia and appearance of a dark or pale black dapple on the fruit surface are typical signs of this disease. The disease was severe during cold storage of the Niitaka and Chuhwangbae varieties, but more limited on the Gamcheonbae and Hwangkeumbae varieties. To identify causal pathogens, 123 fungal isolates were obtained from lesions. The fungi that caused typical skin sooty dapple disease symptoms in our bioassay were identified. Based on their morphological characteristics, 74% of the isolates were Cladosporium sp. and 5-7 % of the isolates were Leptosphaerulina sp., Tripospermum sp., or Tilletiopsis sp. None of the isolates caused severe soft rot by injection to a wound plug, but some of the Cladosporium sp. isolates caused mild maceration. Therefore this microbiol complex cannot account for the soft rot also observed in stored fruits. The high frequency of isolation of Cladosporium sp. from disease tissues and bioassay on pear fruit surface suggest that Cladosporium sp. could be a major pathogen in the microbial complex associated with skin sooty dapple disease of the Asian pear in Korea.

• Microbiology and Biotechnology Letters
• /
• v.27 no.6
• /
• pp.477-483
• /
• 1999

For Trametes sp. CJ-105, a kind of white-rot fungi which was collected from the mountain of Korea and was proven to be effective in decolorizing a wide range of structurally different synthetic dyes, the optimum conditions for mycelial growth and laccase(E.C. 1.10.3.2) production were investigated. Among various carbon sources, glucose showed the highest potential for the mycelial growth and laccase production, the optimum concentration being 2% glucose. For the nitrogen source, asparagine was good for the mycelial growth, while ammonium tartrate for laccase production(optimum concentration: 0.04%). The addition of thiamine and biotin increased both th emycelial growth and laccase production. When 2,5-xylidine was added as an inducer after the first day of culture, the production of alccase was seven-times higher than that in the absence of the inducer. The optimum pH and temperature conditions for laccase production by Trametes sp. CJ-105 were pH 5.0 and $25^{\circ}C$, respectively. In the 5L fermentation, the production of laccase reached a maximum of 340U/ml at the time when the ammonium ion was being rapidly depleted.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.3
• /
• pp.468-473
• /
• 2007

White rot fungi, Phanerochaete chrysosporium and Phanerochaete sordida, have been mostly studied in a variety of industrial processes like biopulping and pulp bleaching as well as in bioremediation. Whereas P. sordida is widely distributed in the North Temperate Zone, P. chrysosporium is reported in the restricted area and hundreds of reports have been described from a few strains of P. chrysosporium, which are deposited at various fungal collections in the world. The isolates of two species are not easily discriminated because of their morphological and molecular similarity. Through the ITS sequence analyses, a region containing substantial genetic variation between the two species was identified. PCR amplification using two specific primers was successfully used to differentiate P. chrysosporium from P. sordida. These results were supported by cultural studies. The growth rates at $37^{\circ}C$ on PDA, MEA, and Cza and the microscopic features of conidia on PDA and YMA were also very useful to differentiate those two species.

• Mycobiology
• /
• v.41 no.1
• /
• pp.37-41
• /
• 2013

Laccases (EC 1.10.3.2) are copper-containing polyphenol oxidases found in white-rot fungi. Here, we report the cloning and analysis of the nucleotide sequence of a new laccase gene, fvlac7, based on the genomic sequence of Flammulina velutipes. A primer set was designed from the putative mRNA that was aligned to the genomic DNA of F. velutipes. A cDNA fragment approximately 1.6-kb long was then amplified by reverse transcriptase-PCR using total RNA, which was subsequently cloned and sequenced. The cDNA sequence of fvlac7 was then compared to that of the genomic DNA, and 16 introns were found in the genomic DNA sequence. The fvlac7 protein, which consists of 538 amino acids, showed only 42~51% identity with 12 different mushroom species containing two laccases of F. velutipes, suggesting the fvlac7 is a novel laccase gene. The first 25 amino acids of Fvlac7 correspond to a predicted signal sequence, four copper-binding sites, and four N-glycosylation sites. Fvlac7 cDNA was heterologously overexpressed in an Escherichia coli system with an approximate expected molecular weight of 60 kDa.

• Journal of Microbiology
• /
• v.44 no.3
• /
• pp.263-268
• /
• 2006

Pleurotus ostreatus is a widely cultivated white-rot fungus. Owing to its considerable enzymatic versatility p. ostreatus has become the focus of increasing attention for its possible utility in biobleaching and bioremediation applications. Interactions between microorganisms can be an important factor in those processes. In this study, we describe the presence of a bacterial species associated with P. ostreatus strain G2. This bacterial species grew slowly (approximately 30 days) in the liquid and semi-solid media tested. When p. ostreatus was inoculated in solid media containing Tween 80 or Tween 20, bacterial microcolonies were detected proximal to the fungal colonies, and the relevant bacterium was identified via the analysis of a partial 16S rDNA sequence; it was determined to belong to the Burkholderia cepacia complex, but was not closely related to other fungus-isolated Burkholderiaceae. New specific primers were designed, and confirmed the presence of in vitro P. ostreatus cultures. This is the first time that a bacterial species belonging to the B. cepacia complex has been found associated with P. ostreatus.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.29 no.2
• /
• pp.83-90
• /
• 1997

An unbleached hardwood kraft pulp was bleached in vitro with partially purified manganese peroxidase (MnP) from the fungus Phanerochaete sordida YK-624 without the addition of MnSO$_4$ in the presence of oxalate, malonate or gluconate known as manganese chelator, When the pulp was treated without the addition of MnSO$_4$, the pulp brightness increased by about 10 points in the presence of 2 mM oxalate, but the brightness did not significantly increase in the presence of 50 mM malonate. Residual MnP activity decreased faster during the bleaching with MnP without MnSO$_4$ in the presence of malonate than in the presence of oxalate. Oxalate reduced MnO$_2$ which already existed in the pulp or was produced from $Mn^{2+}$ by oxidation with MnP and thus supplied $Mn^{2+}$ to the MnP system. Thus, bleaching of hardwood kraft pulp with MnP, using manganese originally existing in the pulp, became possible in the presence of oxalate, a good manganese chelator and reducing reagent. Properties of partially purified MnPs from liquid cultures of white rot fungi, Ganoderma sp. YK-505, Phanerochaete sordida YK-624 and Phanerochaete chrysosporium were compared. MnP from Ganoderma sp. YK-505 was superior to MnPs from P. sordida YK-624 and P. chrysosporium in stabilities against high temperature and high concentration of $H_2O$$_2$. The MnP from Ganoderma sp. YK-505 differed in pH-activity profile from other MnPs. These data suggest that MnP from Ganoderma sp. YK-505 has different structure from those of other fungi. Bleaching of hardwood kraft pulp using the MnP from ganoderma sp. YK-505 is now in progress.

• Journal of Mushroom
• /
• v.17 no.4
• /
• pp.247-254
• /
• 2019

Trametes hirsuta, a white rot fungus, exhibits the ability to degrade synthetic aromatic dyes such as congo red (CR), methylene blue (MB), crystal violet (CV), and remazol brilliant blue R (RBBR). The mycelia of T. hirsuta degraded RBBR and CR more efficiently than CV and MB in the PDB liquid medium (supplemented with 0.01% 4 aromatic dyes). In these mycelia the activities of three ligninolytic enzymes-laccase, manganese peroxidase (MnP), and lignin peroxidase (LiP)-were observed. Among these, laccase was identified to be the major enzyme responsible for the degradation of the four aromatic dyes. The degradation of bisphenol A was also investigated by culturing the mycelia of T. hirsuta in YMG medium supplemented with 100 ppm bisphenol A. The mycelia of T. hirsuta were found to degrade bisphenol A by 71.3, 95.3, and 100 % within incubation periods of 12, 24, and 36 hr, respectively. These mycelia also showed ligninolytic enzyme-like activities including those similar to laccase, MnP, and LiP. Therefore, these results indicate that T. hirsuta could emerge as a potential tool for the remediation of environmental contamination by aromatic dyes and bisphenol A.

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

• 한국균학회소식:학술대회논문집
• /
• 2014.05a
• /
• pp.43-43
• /
• 2014

White rot fungi have been useful source of enzymes for the degradation of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) and synthetic dyes. PAHs are widespread organic compounds present in fossil fuels and are routinely generated by incomplete fuel combustion. PAHs are some of the major toxic pollutants of water and soil environments. Synthetic dyes are major water-pollutants, which are toxic to organisms in water environments and interfere photosynthesis of water plants. Removal of PAHs and synthetic dyes has been of interests in the environmental science especially in the environmental microbiology. Mushrooms are fungal groups that function as primary degraders of wood polyphenolic lignin. The ligninolytic enzymes produced by mushroom, including manganese peroxidase, lignin peroxidase, and laccase, mediate the oxidative degradation of lignin. The catalytic power of these enzymes in the degradation of aromatic ring compounds has been sought for the degradation of various organic compounds. In this project, we have screened 60 wild mushroom strains for their degradation activity against two representative PAHs, naphthalene and anthracene, and five aromatic dyes, including alizarin red S, crystal violet, malachite green, methylene blue, rose bengal. The degradation of PAHs was measured by GC while the decolorization of dyes was measured by both UV spectrophotometer and HPLC. As results, 9 wild mushroom strains showed high activity in degradation of PAHs and textile dyes. We also describe the secretive enzyme activities, the transcription levels, and cloning of target genes. In conjunction with this, activities of degradative enzymes, including laccase, lignin peroxidase, and Mn peroxidase, were measured in the liquid medium in the presence of PAHs and dyes. Our results showed that the laccase activity was directed correlated with the degradation, indicating that the main enzyme acts on PAHs and dyes is the laccase. The laccase activity was further simulated by the addition of $Cu^{2+}$ ion. Detailed studies of the enzyme system should be sought for future applications.

• Korean Journal of Microbiology
• /
• v.46 no.1
• /
• pp.93-95
• /
• 2010

White rot fungi which have lignin degrading enzymes show high degrading activity to diverse recalcitrant compounds such as polycyclic aromatic compounds, dyes, explosives and endocrine disrupting chemicals. We have examined decolorizing activity of dyes by Phlebia tremellosa and two transformants which had genetically transformed using laccase or manganese peroxidase (MnP) gene. In case of methyl green, wild type strain showed 50% decolorization while laccase transformant (TF2-1) and MnP transformant (T5) showed more than 90% decolorization on day 3. Remazol brilliant blue R(RBBR) was decolorized up to 85% by two transformants while the wild type showed 67% decolorization on day 3. Transformants TF2-1 and T5 both showed increased laccase and MnP activity respectively during the whole growing phase.