• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.41-41
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• 2014

Pinewood nematode (PWN, Bursaphelenchus xylophilus) is a serious pathogenic worm that quickly dry pine trees to death. Recently, PWN has been devastating huge amounts of conifer trees in Korea. As a first step to explore the association and ecological roles of fungi in PWN life cycle in Korea, in this study we first isolated and indentified fungi from PWN-infested Korean pine and Japanese black pine wood sampled in Jinju, Sacheon, Pocheon, Chuncheon, Gwangju, and Hoengseong in Korea. A total of 144 fungal isolates were obtained from Japanese black pine wood and 264 fungal isolates from Korean pine wood. Their morphology and nucleotide sequences of the ITS rDNA and ♌-tubulin gene were examined for species identification. Ophiostoma ips, Botrytis anthophila, Penicillium sp., Hypocrea lixii, Trichoderma atroviride, O. galeiforme, Fusarium proliferatum were identified from Japanese black pine wood. Leptographium koreanum, L. pini-densiflorae, Ophiostoma ips, Penicillium raistrick, Trichoderma sp. were isolated from Korean pine wood. O. ips and L. koreanum were the major species on the two different PWN-infected pine tree. The cultivation of PWN on fungal mat of the identified species did some enhance PWN reproduction. The ambrosia beetle, Platypus koryoensis, is a serious pest of oak trees in Korea. In this study we investigated filamentous fungi present in the body of the beetle. Fourteen genera of filamentous fungi belonging to Ascomycota and Basidiomycota were isolated. All the obtained genera were isolated in the mitosporic state. The identified fungi were classified in 11 distinct orders including the Ascomycota (Eurotiales, Hypocreales, Microascales, Ophiostomatales, Pleosporales, and Sordiales) and Basidiomycota (Agaricales, Corticiales, Polyporales, and Russulales Xylariales). Within Ascomycota, 13 species were found. Meanwhile five species were found within Basidiomycota. The results showed the presence of diverse fungi in P. koryoensis. Among the isolated fungi, some were able to produce wood degrading enzymes. Further fungal isolation was performed with P. koryoensis infested Quercus mongolica trees sampled at Kumdan mountain in Hanam-Si, Gyeonggi province from June of 2009 to June of 2010. Penicillin spp. and Trichoderma spp. were the major species of mold fungi group. Pichia guilliermondii was the major species of mold yeast group. Raffaelea quercus-mongolicae was also isolated, but its isolation frequency was not high. Other species identified were Ambrosiella xylebori, Fusarium solani, Cryphonectria nitschke, Chaetomium globosum, and Gliocladium viride, Candida kashinagacola, C. maritima, C. vanderkliftii, Saccharomycopsis crataegensis.

• Journal of Applied Biological Chemistry
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• v.44 no.3
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• pp.147-153
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• 2001

Methanol extracts from 51 fruits were tested for their fungicidal activities against six phytopathogenic fungi in a greenhouse. The efficacy varied with both the plant pathogen and fruit species used. At 10 and 5 mg/pot, methanol extracts of Poncirus trifoliata peel and seed gave over 80% control values against Pyricularia grisea, and strong fungicidal activities against Rhizoctonia solani were showed from the extracts of Citrus paradisi peel and Punica granatum leaf. In a test with Botrytis cinerea at 5 mg/pot, the extracts of C. sinensis seed and D. kaki leaf produced potent fungicidal activities, and the extracts of C. crenata peel and leaf, Ch. sinensis seed, P. trifoliata peel, and Z. jujuba leaf had strong fungicidal activities. At 5 mg/pot, strong fungicidal activities were produced in the extracts of P. trifoliata peel and seed against Phytophthora infestans and in the extracts of P. ussriensis var. macrostipes fruit and seed, C. crenata peel, C. crenata leaf, C. paradisi peel, P. trifoliata peel, P. granatum peel, and Z. jujuba leaf against Puccinia recondita. In a test with E. graminis, potent activities at 10 mg/pot were produced from the extracts of Ch. sinensis seed, C. sinensis seed, P. trifoliata leaf, P. ussriensis var. macrostipes fruit and seed, and Vitis vinifera seed. In the control effect of seven extracts against B. cinerea strains resistant to carbendazim, procymidone, and diethofencarb, extracts of C. crenata peel and leaf, Ch. sinensis seed, and P. trifoliata peel were highly effective against all strains of B. cinerea. Furthermore, potent fungicidal activities were produced from the extracts of C. sinensis seed and D. kaki leaf against the SSR, SRR, and RRS, and Z. jujuba leaf against the SSR and RRS strains. As a naturally occurring fungicide, these fruit-derived materials could be useful as new fungicidal products against phytopathogenic fungi.

• Journal of Microbiology
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• v.45 no.5
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• pp.422-430
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• 2007

Clonostachys rosea (syn. Gliocladium roseum) is a well-known biocontrol agent and widely distributed around the world. In this study, an endochitinase gene Crchi1 was isolated from the mycoparasitic fungus C. rosea using the DNA walking strategy. The Crchi1 ORF is 1,746 bp long and interrupted by three introns. The cloned gene Crchi1 encodes 426 amino acid residues and shares a high degree of similarity with other chitinases from entomopathogenic and mycoparasitic fungi. Several putative binding sites for transcriptional regulation of Crchi1 in response to carbon (5'-SYGGRG-3') and nitrogen (5'-GATA-3') were identified in the upstream of Crchi1. Expression of Crchi1 gene in different carbon sources was analyzed using real-time PCR (RT-PCR). We found that the Crchi1 expression was suppressed by glucose but strongly stimulated by chitin or solubilized components of the cell wall from Rhizoctonia solani. Phylogenetic analysis of chitinases from entomopathogenic and mycoparasitic fungi suggests that these chitinases have probably evolved from a common ancestor.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.378-381
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• 2014

A new pathogen was isolated from zoysiagrass-planted park of Jeju island in 2014. Symptoms appeared a type of irregular patches occurring brownish leaf blight, followed by stem and crown rot. The symptom was very similar to that of large patch caused by Rhizoctonia solani, a well-known devastating zoysiagrass disease. The isolate showed thin orange-colored mycelia and screlotia were formed on the medium based on cultural characteristics. The causal agent of the disease was finally identified as Waitea circinata by analysis of ribosomal DNA. On the inoculation test, Waitea circinatae showed strong pathogenicity to the zoysiagrass. The mycelia were obviously observed in the inoculated tissues. This is the first report of Waitea ring patch caused by Waitea circinata on zoysiagrass.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.333-343
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• 2009

Here, we show that an endophytic bacterial strain, Enterobacter asburiae B1 exhibits the ability to elicit ISR in cucumber, tobacco and Arabidopsis thaliana. This indicates that strain B1 has a widespread ability to elicit ISR on various host plants. In this study, E. asburiae strain B1 did not show antifungal activity against tested major fungal pathogens, Colletotrichum orbiculare, Botrytis cinerea, Phytophthora capsici, Rhizoctonia solani, and Fusarium oxysporum. Moreover, the siderophore production by E. asburiae strain B1 was observed under in vitro condition. In greenhouse experiments, the root treatment of strain B1 significantly reduced disease severity of cucumber anthracnose caused by fungal pathogen C. orbiculare compared to nontreated control plants. By root treatment of strain B1 more than 50% disease control against anthracnose on cucumber was observed in all greenhouse experiments. Simultaneously, under the greenhouse condition, the soil drench of strain B1 and a chemical inducer benzothiadiazole (BTH) to tobacco plants induced GUS activity which is linked with activation of PR promoter gene. Furthermore, in Arabidopsis thaliana plants the soil drench of strain B1 induced the defense gene expression of PR1 and PDF1.2 related to salicylic acid and jasmonic acid/ethylene signaling pathways, respectively. In this study, for the main focus on root colonization by strain B1 associated with defense responses, bacterial cells of strain B1 was tagged with the gfp gene encoding the green fluorescent protein in order to determine the colonization pattern of strain B1 in cucumber. The gfp-tagged B1 cells were found on root surface and internal colonization in root, stem, and leaf. In addition to this, the scanning electron microscopy observation showed that E. asburiae strain B1 was able to colonized cucumber root surface.

• Molecules and Cells
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• v.28 no.4
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• pp.321-329
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• 2009

Rapid production of nitric oxide (NO) and reactive oxygen species (ROS) has been implicated in the regulation of innate immunity in plants. A potato calcium-dependent protein kinase (StCDPK5) activates an NADPH oxidase StRBOHA to D by direct phosphorylation of N-terminal regions, and heterologous expression of StCDPK5 and StRBOHs in Nicotiana benthamiana results in oxidative burst. The transgenic potato plants that carry a constitutively active StCDPK5 driven by a pathogen-inducible promoter of the potato showed high resistance to late blight pathogen Phytophthora infestans accompanied by HR-like cell death and $H_2O_2$ accumulation in the attacked cells. In contrast, these plants showed high susceptibility to early blight necrotrophic pathogen Alternaria solani, suggesting that oxidative burst confers high resistance to biotrophic pathogen, but high susceptibility to necrotrophic pathogen. NO and ROS synergistically function in defense responses. Two MAPK cascades, MEK2-SIPK and cytokinesis-related MEK1-NTF6, are involved in the induction of NbRBOHB gene in N. benthamiana. On the other hand, NO burst is regulated by the MEK2-SIPK cascade. Conditional activation of SIPK in potato plants induces oxidative and NO bursts, and confers resistance to both biotrophic and necrotrophic pathogens, indicating the plants may have obtained during evolution the signaling pathway which regulates both NO and ROS production to adapt to wide-spectrum pathogens.

• Journal of Environmental Science International
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• v.29 no.5
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• pp.435-443
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• 2020

The purpose of this study was to investigate eco-friendly measures to manage major diseases which cause heavy economic damages to ginseng. Morphological, physicochemical, and molecular biological species identification was carried out after isolating useful antagonistic bacteria from ginseng fields. In addition, optimal conditions for mass culture were established, and he efficacy of the bacteria in the prevention of the diseases was verified in the field. The results showed that about 150 bacteria were extracted from 150 ginseng fields in the whole county. Among them, B. pyrrocinia LA101 was finally selected, which had a strong antagonistic potency against Alternaria panax, Botrytis cinerea, Rhizoctonia solani, and Cylindrocarpon destructans on agar media. The B. pyrrocinia LA101 is a baculiform gram-negative bacterium identified as Burkholderia pyrrocinia according to results from an API(Analytical Profile Index) kit, 16S rRNA, and gyrase gene sequencing analysis. It was donated to the microbe bank of the Agricultural Genetic Resources Center at the National Academy of Agriculture Science under the Rural Development Administration on September 28, 2011 (Donation No. KACC91663P). A patent for the mass culture technology was granted in August 2012 (Patent No. 10-1175532).

• The Plant Pathology Journal
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• v.38 no.3
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• pp.182-193
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• 2022

Turfgrass, the most widely grown ornamental crop, is severely affected by fungal pathogens including Sclerotinia homoeocarpa, Rhizoctonia solani, and Magnaporthe poae. At present, turfgrass fungal disease management predominantly relies on synthetic fungicide treatments. However, the extensive application of fungicides to the soil increases residual detection frequency, raising concerns for the environment and human health. The bacterial volatile compound, 2,3-butanediol (BDO), was found to induce plant resistance. In this study, we evaluated the disease control efficacy of a combination of stereoisomers of 2,3-BDO and commercial fungicides against turfgrass fungal diseases in both growth room and fields. In the growth room experiment, the combination of 0.9% 2R,3R-BDO (levo) soluble liquid (SL) formulation and 9% 2R,3S-BDO (meso) SL with half concentration of fungicides significantly increased the disease control efficacy against dollar spot and summer patch disease when compared to the half concentration of fungicide alone. In field experiments, the disease control efficiency of levo 0.9% and meso 9% SL, in combination with a fungicide, was confirmed against dollar spot and large patch disease. Additionally, the induction of defense-related genes involved in the salicylic acid and jasmonic acid/ethylene signaling pathways and reactive oxygen species detoxification-related genes under Clarireedia sp. infection was confirmed with levo 0.9% and meso 9% SL treatment in creeping bentgrass. Our findings suggest that 2,3-BDO isomer formulations can be combined with chemical fungicides as a new integrated tool to control Clarireedia sp. infection in turfgrass, thereby reducing the use of chemical fungicides.

• Journal of Microbiology
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• v.41 no.3
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• pp.196-201
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• 2003

The object of this study was to characterize Bacillus strains GB-017 and GB-0356, which produce antifungal substances, especially for plant pathogens. In addition, this study was undertaken to characterize the culture conditions required for the production of antifungal substances and to document some of the properties of the antifungal substance produced by these soil-isolated strains. Strains GB-0365 and GB-017 were found to be bacillus-shaped, gram-positive and motile, and to inhibit Botrytis cineria, Fusarium sp., Pythium sp., and Rhizoctonia solani. Antagonistic activity was maintained up to pH 9.0, and the antifungal activity was stable to heat at 80$^{\circ}C$ for 1 h. Antifungal substances were separated and purified using ion exchange and adsorption columns including WK-I0(H$\^$＋) (pH 7.0), HP20 column (pH 3.0) and IPA (pH 3.0). and IPA. Its UV absorption spectrum showed major peaks at 231 and 259 nm, corresponding to polyene and lactone. A fast atom bombardment mass spectrum (FAB MS) showed a highest peak at 441 m/z and major peaks at 192, 205, and 370 m/z.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.672-676
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• 2006

The aim of this study is to evaluate the antioxidant, antimicrobial, and antitumor activities of various concentrations of partially purified substance(s) from green tea seed (Camellia sinensis L.). The total polyphenol contents of each fraction (non-adsorption fraction: F-1, fraction eluted with 40% methanol: F-2, and fraction eluted with 100% methanol: F-3) purified by Diaion HP-20 column chromatography were, in the increasing order: F-1 (3.7 mg tannic acid equivalents, TAB/g) < F-3 (23.2 mg TAB/g) < seed extracts (26.2 mg TAB/g) < F-2 (42.7 mg TAB/g). The scavenging activities toward the 1,1-diphenyl-2-picyrylhydrazyl (DPPH) radical were, in decreasing order: F-2 (93.3%) > butylated hydroxytoluene (BHT; 89.8%) > ascorbic acid (89.3%) > leaf extracts (70.3%) > F-3 (15.9%) > seed extracts (15.8%) > F-1 (14.8%) at a 0.1% concentration. In studies on antimicrobial activities, the results indicate that the growth of yeast (Candida albicans KCCM 11282 and Cryptococcus neoformans KCCM 50544) was inhibited more so than that of other fungi (Alternaria alternate KCTC 6005 and Rhizoctonia solani). In addition, it appears that the antitumor activities of the F-1, F-2, and F-3 fractions at a concentration of $50\;{\mu}g/mL$ showed 6, 7, and 23% growth inhibition of the HEC-1B cell line, 14, 11, 82% inhibition of the HEP-2 cell line, and 8, 16, and 81% inhibition of the SK-OV-3 cell line, respectively. Overall these results indicate that the antioxidant activity is greatest in the F-2 fraction, and the antimicrobial and antitumor activities are greatest in the F-3 fraction.