• The Plant Pathology Journal
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• v.40 no.3
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• pp.235-250
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• 2024

During the infection process, plant pathogenic fungi encounter plant-derived oxidative stress, and an appropriate response to this stress is crucial to their survival and establishment of the disease. Plant pathogenic fungi have evolved several mechanisms to eliminate oxidants from the external environment and maintain cellular redox homeostasis. When oxidative stress is perceived, various signaling transduction pathways are triggered and activate the downstream genes responsible for the oxidative stress response. Despite extensive research on antioxidant systems and their regulatory mechanisms in plant pathogenic fungi, the specific functions of individual antioxidants and their impacts on pathogenicity have not recently been systematically summarized. Therefore, our objective is to consolidate previous research on the antioxidant systems of plant pathogenic fungi. In this review, we explore the plant immune responses during fungal infection, with a focus on the generation and function of reactive oxygen species. Furthermore, we delve into the three antioxidant systems, summarizing their functions and regulatory mechanisms involved in oxidative stress response. This comprehensive review provides an integrated overview of the antioxidant mechanisms within plant pathogenic fungi, revealing how the oxidative stress response contributes to their pathogenicity.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.89.1-89
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• 2003

Disease suppression by ectomycorrhizal(ECM) fungi has been demonstrated on red pine seedlings. Culturing of pathogenic fungi on petri plates containing culture filtrates of ECM fungi showed that culture filtrates of the ECM fungus Hebeloma cylindrosporum may inhibit the mycelial growth of all tested soil-borne plant pathogenic(SBPP) fungi upto 60％, In order to examine the effects of ECM fungi on SBPP fungi and on red pine seedlings, both symbiotic and pathogenic fungi were inoculated into the soil with red pine seedlings by three inoculation methods; pre-inoculation of SBPP fungi 10 days before inoculation of ECM fungi, simultaneous inoculation of both fungi, post-inoculation of SBPP fungi 60 days after inoculation of ECM fungi. Seedling mortality, seedling growth, and ectomycorrhizal formation by the combined treatments were examined and compared. Pine seedlings were dead by the pre-inoculation of pathogenic fungi, except Rhizina undulate which required 9-12 days, within 6 days after inoculation. Among pathogenic fungi tested, Fusarium oxysporum was the most pathogenic with the mortality of 44％. However, no dead seedlings were shown by simultaneous inoculation of both fungi or pre-inoculation of ECM fungi. In addition, pine seedlings treated by simultaneous or post-inoculation of SBPP fungi were relatively higher than those treated by pre-inoculation in diameter at root crown and the number of ectomycorrhizal roots. There were no significant differences among inoculation methods in root length and dry weight of treated seedlings. It means that ECM fungi somehow play a role in protecting primary roots of red pine seedlings against invasion by the SBPP fungi.

• Mycobiology
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• v.40 no.1
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• pp.53-58
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• 2012

This research is concerned with the fungicidal properties of nano-size silver colloidal solution used as an agent for antifungal treatment of various plant pathogens. We used WA-CV-WA13B, WA-AT-WB13R, and WA-PR-WB13R silver nanoparticles (AgNPs) at concentrations of 10, 25, 50, and 100 ppm. Eighteen different plant pathogenic fungi were treated with these AgNPs on potato dextrose agar (PDA), malt extract agar, and corn meal agar plates. We calculated fungal inhibition in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. The results indicated that AgNPs possess antifungal properties against these plant pathogens at various levels. Treatment with WA-CV-WB13R AgNPs resulted in maximum inhibition of most fungi. Results also showed that the most significant inhibition of plant pathogenic fungi was observed on PDA and 100 ppm of AgNPs.

• The Plant Pathology Journal
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• v.18 no.4
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• pp.169-178
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• 2002

Orchids are evolutionally known to be the most advanced plants in the order Liliales, and comprise approximately 1,000 genera and 35,000 species world-wide. In Korea, more than 110 species of Orchidaceae have been reported to be cultivated or to be collected in the wild. Orchids aye mostly dependant on orchid mycorrhizae(OM) throughout or in part of their life cycle. The OM endomycorrhizae belonging to basidiomycetes or rarley ascomycetes are needed for orchid seed germination. Various fungi, including plant pathogenic, antagonistic and symbiotic fungi, were isolated from the roots of orchid native to Korea. The OM fungi collected from the roots of Cymbidium goeringii were three species of Rhizoctonia namely, R. repens (anamorph state of Tulsanella repens), R. endophytica (Ceratobasidium cornigerum), and an unidentified species (possibly an anamorph of T. calospora). These symbiotic fungi induced peloton in the cortical cells of orchid roots, and differed biologically and in 18s rDNA sequences from plant pathogenic Rhizoctonia species. Also, the mycorrhyzal fungi enhanced the orchid root absorption of nitrogen sources and minerals from the soil. The activity of mycorrhizal fungal hyphae in the roots caused prevention from pathogenic fungi. In nature, the peloton is observed in the cortical cells of Cymbidium goeriingii roots, indicating mycorrhizal colonization in the native orchid roots. On the other hand, pathogenic fungi such as Fusarium and/or Rhizoctonia species are mostly isolated from commercial orchid plants. These suggest that application of symbiotic mycorrhizal fungi should be needed for orchid cultivation in nurseries and at the time of transplanting.

• The Plant Pathology Journal
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• v.37 no.6
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• pp.505-511
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• 2021

Interaction of a pathogen with its host plant requires both flexibility and rapid shift in gene expression programs in response to environmental cues associated with host cells. Recently, a growing volume of data on the diversity and ubiquity of internal RNA modifications has led to the realization that such modifications are highly dynamic and yet evolutionarily conserved system. This hints at these RNA modifications being an additional regulatory layer for genetic information, culminating in epitranscriptome concept. In plant pathogenic fungi, however, the presence and the biological roles of RNA modifications are largely unknown. Here we delineate types of RNA modifications, and provide examples demonstrating roles of such modifications in biology of filamentous fungi including fungal pathogens. We also discuss the possibility that RNA modification systems in fungal pathogens could be a prospective target for new agrochemicals.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.189-199
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• 2000

To search for the antifungal substances, various actino-mycete isolates were obtained from various soils of Korea using plate dilution method on the humic acid vitamin agar plates. In the screening procedures using a dual culture method, 32 actionomycete isolates were selected, which showed the inhibitory activity against mycelial growth of plant pathogenic fungi Altirnaria mali, Colletotrichum gloeosporides, Fusarium oxysporum f.sp. cucumerinum, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. Bioassay of the crude extracts from culture filtrates and mycelial mets revealed that 12 antagonistic actionomycetes produced highly active antifungal substances. Actinomycete strain S5-55 which showed the substantial antifungal activity against the tested fungi was selected for production of the antifungal substances. Based on the cytochemical and morphological characteristics, strain S5-55 was identified as a Streptomyces species. The results of the numerical identification using the TAXON program confirmed that Streptomyces strain S5-55 was identical with Streptomyces humidus including in TAXON major cluster 19. The production of antifungal substance was most favorable when S. humidus strain S5-55 was cultivated for 10 dats on soluble starch broth supplemented with $K_2$HPO$_4$. The antifungal substances active against the plant pathogenic fungi P. capsici and M. grisea were partially purified using $\textrm{C}_{18}$ reversed-phase column chromatography.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.191-202
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• 1998

About 300 actinomycetes were isolated from two forest and one sea-shore soil and tested for inhibitory effects on mycelial growth of six plant pathogenic fungi Magnaporthe grisea, Alternaria mali, Colletotrichum gloeosporioides, Phytophthora capsici, Fusarium oxysporum f. sp. cucumerinum, and Rhizoctonia solani. Among 300 actinomycetes tested, only 16 actinomycetes showed the antifungal activity against the test fungi. Isolate NH 50 was selected for production and purification of antifungal antibiotic substances. Actinomycete isolate NH 50 displayed the broad antifungal spectra against 11 plant pathogenic fungi. To identify actinomycete isolate NH 50, cultural characteristics on various agar media, diaminopimelic acid type, and morphological characteristics by scanning electron microscopy were examined. As a result, actinomycete isolate NH 50 was classified as a rare actinomycete that had LL-DAP type and did not produce spores. After incubation of isolate NH 50 in yeast extract-malt extract-dextrose broth, antifungal compound NH-B1 that inhibited mycelial growth of some plant pathogenic fungi was purified from the methanol eluates of XAD-16 resins by a series of purification procedures, i.e., silica gel flash chromatography, C18 flash chromatography, Sephadex LH-20 column chromatography, silica gel medium pressure liquid chromatography (MPLC), C18 MPLC, and high pressure liquid chromatography (HPLC). UV spectrum and 1HNMR spectrum of antifungal compound NH-B1 dissolved in methanol were examined. The antibiotic NH-B1 showed the major peaks at 230 and 271.2nm. Based on the data of 1H-NMR spectrum, NH-B1 was confirmed to be an extremely complex polymer of sugars called polysaccharides. The antibiotic NH-B1 showed strong antifungal activity against Alternaria solani and Cercospora kikuchi, but weak activity against M. grisea.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.1003-1008
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• 2004

11 plant essential oils are screened in vitro for their antifungal activities against Botrytis cinerea, Fusarium oxysporum and Rhizoctonia solani, which are causative agents of serious plant diseases. The radial growth of the test fungi were reduced in response to the oils. Among them, the essential oil from the bark of Cinnamomum zeylanicum inhibited 3 tested fungi growth, strongly, followed by those of oregano and thyme. The major constituents of the three essential oils, cinnaldehyde, carvacrol and thymol were tested for their effects on the fungi. From the results obtained, cinnamaldehyde, the major constituents of C. zeylanicum bark esential oil, has potential to be developed as a biopesticide for controlling phytopathogenic fungi causing serious damages on the important crops cultivated in Korea.

• The Plant Pathology Journal
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• v.22 no.4
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• pp.381-385
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• 2006

Antifungal activity of Korean and Chinese lichen-forming fungi(LFF) was evaluated against plant pathogenic fungi of Botryosphaeria dothidea, Botrytis cinerea, Diaporthe actinidiae, Pestalotiopsis longiseta, Pythium sp., Rhizoctonia solani, and Sclerotium cepivorum. The LFF were isolated from Cladonia scabriuscula, Melanelia sp., Nephromopsis asahinae, Nephromopsis pallescens, Parmelia laevior, Pertusaria sp., Ramalina conduplicans, Ramalina sinensis, Ramalina sp., Umbilicaria proboscidea and Vulpicida sp. with discharged spore method. The isolates were deposited in the herbarium of Korean Lichen Research Institute(KoLRI) in Sunchon National University. The LFF of Melanelia sp., P. laevior, Pertusaria sp., R. conduplican and Ramalina sp. exhibited strong antifungal activity against all of the pathogenic fungi examined. Among them, LFF of P. laevior showed more than 90% of inhibition in fungal hyphae growth, compared with control. The results imply that LFF can be served as a promising bioresource to develop novel biofungicides. Mass cultivation of the LFF is now under progress in laboratory conditions for chemical identification of antifungal substances.

• Mycobiology
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• v.31 no.2
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• pp.68-73
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• 2003

Roots of Glycine max and Miscanthus sinensis and soil samples were collected from various field sites at Goesan, Chungbuk in Korea. Microscopic observations of the roots indicated high colonization rates of both arbuscular mycorrhizal fungi(AMF) and other fungi. The partial small subunit of ribosomal DNA genes were amplified with the genomic DNA extracted from their roots by nested polymerase chain reaction(PCR) with universal primer NS1 and fungal specific primers AML Restriction fragment length polymorphism(RFLP) was analyzed using the combinations of three restriction enzymes, HinfI, AluI and AsuC21. Nucleotides sequence analysis revealed that ten sequences from Miscanthus sinensis and one sequence from Glycine max were close to those of arbuscular mycorrhizal fungi. Also, 33% of total clones amplified with NS31-AM1 primers from M. sinensis and 97% from G. max were close to Fusarium oxysporum or other pathogenic fungi, and they were successfully distinguished from AME Results suggested that these techniques could help to distinguish arbuscular mycorrhizal fungi from root pathogenic fungi in the plant roots. Especially, DNA amplified by these primers showed distinct polymorphisms between AMF and plant pathogenic species of Fusarium when digested with AsuC21.