• 식물병연구
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• 제26권1호
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• pp.38-43
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• 2020

The genome of the rice blast fungus Magnaporthe oryzae contains several types of transposable elements (TEs), and some TEs cause genetic variation that allows M. oryzae to evade host detection. We studied how five abundant TEs in rice pathogens, Pot3, Pot2, MAGGY, Line-like element (MGL) and Mg-SINE, are expressed under diverse conditions related to growth, development, and stress. Expression of Pot3 and Pot2 was activated in germinated conidia and mycelia treated with tricyclazole. Retrotransposon MAGGY was highly expressed in appressoria and tricyclazole-treated mycelia. MAGGY and Pot2 were also activated during the early and late stages of perithecia development. MGL was up-regulated in conidia and during conidial germination but not during appressorium formation. No noticeable expression of Mg-SINE was observed under most conditions. Our results should help investigate if and how condition-specific expressions of some TEs contribute to the biology and evolution of M. oryzae.

• The Plant Pathology Journal
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• 제17권3호
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• pp.180-183
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• 2001

A corynespora leaf spot of pepper, which has not been reported previously in Korea, occurred severely at the major pepper cultivation area of Chinju, Gyeongnam province in 2001. Infection rate ranged from 48.2 to 84.7% in eight fields surveyed. The causal fungus was identified as Corynespora cassicola based on the following cultural and morphological characteristics. The fungi grew well on potato dextrose agar, showing gray to brown color with cultural age. Conidia formed solitary or catenary were obclavate to cylindrical in shape, and pale olivaceous brown or brown in color. They had 420 pseudoseptate and isthmus, and measured 42.7-197.6 x 9.3-$23.5\mu\textrm{m}$. Septate conidiophores were pale to light brown in color, and measured 116.5-836.0 x 4.2-$11.0\mu\textrm{m}$. Conidia germinated as a bi-polar type. Optimal temperature for mycelial growth and conidial germination was $30^{\circ}$ and 25-$30^{\circ}$, respectively. The fungus showed strong pathogenicity to pepper plant, and the symtoms on pepper by the artificial inoculation were similar to those observed in the field. This is the first report on the corynespora leaf spot on pepper (Capsium annuum) caused by Corynespora cassicola in Korea.

• Mycobiology
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• 제50권6호
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• pp.467-474
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• 2022

Autophagy serves as a survival mechanism and plays important role in nutrient recycling under conditions of starvation, nutrient storage, ad differentiation of plant pathogenic fungi. However, autophagy-related genes have not been investigated in Colletotrichum scovillei, a causal agent of pepper fruit anthracnose disease. ATG8 is involved in autophagosome formation and is considered a marker of autophagy. Therefore, we generated an ATG8 deletion mutant, ΔCsatg8, via homologous recombination to determine the functional roles of CsATG8 in the development and virulence of C. scovillei. Compared with the wild-type, the deletion mutant ΔCsatg8 exhibited a severe reduction in conidiation. Conidia produced by ΔCsatg8 were defective in survival, conidial germination, and appressorium formation. Moreover, conidia of ΔCsatg8 showed reduced lipid amount and PTS1 selectivity. A virulence assay showed that anthracnose development on pepper fruits was reduced in ΔCsatg8. Taken together, our results suggest that CsATG8 plays various roles in conidium production and associated development, and virulence in C. scovillei.

• Natural Product Sciences
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• 제23권2호
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• pp.125-131
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• 2017

Clitoria ternatea or Commonly known blue pea, is a perennial climber crop native to Asian countries. The current study was aimed to evaluate the antimicrobial activity C. ternatea extract on food borne microorganisms and its antifungal effect on Penicillium expansum. The extract showed significant antimicrobial activity against 3 Gram positive bacteria, 2 Gram negative bacteria and 1 filamentous fungus on disc diffusion assay. The extract also showed good biocidal effect on all Gram positive bacteria tested and P. expansum. However, the kill curve analysis revealed that the fungicidal activity of the extract against P. expansum conidia was depend on the concentration of the extract and the time of exposure of the conidia to the extract. The scanning electron micrograph of the extract treated P. expansum culture showed alterations in the morphology of fungal hyphae. The germination of P. expansum conidia was completely inhibited and conidial development was totally suppressed by the extract, suggesting the possible mode of action of anthocyanin. Besides, the extract also exhibited 5.0-log suppression of microbial growth relative to control in the rice model. The results indicate the potential use of the C. ternatea anthocyanin as food biopreservative.

• The Plant Pathology Journal
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• 제28권3호
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• pp.259-269
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• 2012

Protein phosphatase 2A (PP2A), a family of serine/threonine protein phosphatases, plays an important role in balancing the phosphorylation status of cellular proteins for regulating diverse biological functions in eukaryotic organisms. Despite intensive studies in mammals, limited information on its role is available in filamentous fungi. Here, we investigated the functional roles of genes for a putative B' delta regulatory subunit (FgPP2AR) and a catalytic subunit (FgPP2AC) of PP2A in a filamentous ascomycete, Fusarium graminearum. Molecular characterization of an insertional mutant of this plant pathogenic fungus allowed us to identify the roles of FgPP2AR. Targeted gene replacement and complementation analyses demonstrated that the deletion of FgPP2AR, which was constitutively expressed in all growth stages, caused drastic changes in hyphal growth, conidia morphology/germination, gene expression for mycotoxin production, sexual development and pathogenicity. In particular, overproduction of aberrant cylindrical-shaped conidia is suggestive of arthroconidial induction in the ${\Delta}FgPP2AR$ strain, which has never been described in F. graminearum. In contrast, the ${\Delta}FgPP2AC$ strain was not significantly different from its wild-type progenitor in conidiation, trichothecene gene expression, and pathogenicity; however, it showed reduced hyphal growth and no perithecial formation. The double-deletion ${\Delta}FgPP2AR;{\Delta}FgPP2AC$ strain had more severe defects than single-deletion strains in all examined phenotypes. Taken together, our results indicate that both the putative regulatory and catalytic subunits of PP2A are involved in various cellular processes for fungal development in F. graminearum.

• 미생물학회지
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• 제27권1호
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• pp.56-62
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• 1989

Chitin 분해 활성이 높은 Streptomyces 균주들을 인삼재배 토양에서 분리하고, 그 균주들이 인상뿌리 썩음 병균인 Fµsarium solani 에 미치는 길항효과와 그 작용을 조사하였다. 분리된 Streptomyces 중 몇 균주는 F. solani 의 포자발아와 발 아판의 생장을 억제하였고 균사를 분해하였으며, 동시에 세포벽 분해효소로 알려친 Chitinase를 생산하였다. 그중에서도 S alboniger ST 59 와 S. roseolilacinus ST 129 는 길항효과가 아주 좋았는데, 병원균의 분생포자를 두 Streptomyces 의 농축배 양여액에 14일간 처리하였을 때 포지숫자가 처음 정종 정도의 20%로 줄어을였다. 특히 S. alboniger ST 59는 뱅균인 F solani의 분생포자, 균사 뿐만 아니라 분해되기 어려운 후막포자까지도 분해하였다. 이것으로 비푸어 보건데, F. solani의 이 Streptomycetes에 의한 억제작용은 항생물질에 영향을 받은 병균이 Chitinase에 의해 분해된 것으로 생각된다.

• 생명과학회지
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• 제23권12호
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• pp.1415-1419
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• 2013

본 연구에서는 식물병원성 미생물들인 잿빛곰팡이와 Agrobacterium rhizogenes의 전자선에 대한 감수성을 조사하였다. 그 결과, 2 kGy의 전자선량이 잿빛곰팡이의 분생포자 및 Agrobacterium rhizgenes의 세포를 사멸시키는 데에 충분한 것으로 나타났다. 식물 종자의 전자선에 대한 저항성을 조사해 본 결과, 대파, 열무와 오이 종자는 2 kGy의 전자선 조사에서도 발아율이 전혀 영향을 받지 않았고, 쑥갓 종자의 경우에는 발아율에 있어서 근소한 감소를 보였다. 그러나 고추와 상추의 경우에는 전자선 조사에 대해서 대단히 약한 것으로 나타났다. 결과적으로 열무, 오이, 대파 및 쑥갓 종자의 경우에는 식물병원성 미생물의 살균에 필요한 2 kGy의 전자선량을 조사함으로써 발아율에 큰 영향을 미치지 않고 충분한 살균효과를 거둘 수 있을 것으로 판단된다. 그러나 고추와 상추의 경우에는 전자선을 이용한 살균 방법은 사용하기 어려운 것으로 나타났다.

• 농약과학회지
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• 제4권2호
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• pp.37-43
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• 2000

본 시험은 오이 양액재배시 배양액내 규산칼륨($K_{2}SiO_{3}$) 처리에 의한 흰가루병 방제여부를 검토하기 위하여 규산 칼륨($K_{2}SiO_{3}$, $25{\sim}27%$의 $SiO_{2}$ Kanto)을 0.85 mM(50 $mg{\cdot}L-^{-1}$), 1.7 mM(100 $mg{\cdot}L-^{-1}$) 및 3.4 mM(200 $mg{\cdot}L-^{-1}$)의 농도로 배양액에 처리하고 1.7 mM, 8.5 mM, 17 mM 및 34 mM의 농도로 엽면살포하였다. 생육중기(정식 51일)에 규산 3.4 mM 배양액 처리구는 흰가루병 병반면적율이 2.3%로 0.95 mM 처리구의 38.3%에 비해 현저히 억제되었다. 그러나 1.7 mM과 3.4 mM 처리간에는 현저한 차이가 없었다. 배양액내 규산의 농도를 0.05 mM에서 4.10 mM까지 증가시켰을 때 잎당 병반수, 병반면적 및 발아관 길이는 규산의 농도 증가에 따라 감소하였다. 규산을 처리한 잎에서의 분생포자 발아율은 처리농도가 높아질수록 현저하게 감소하였으며, 저농도 처리구(1.40 mM 이하)에서는 $14.7%{\sim}20.3%$, 고농도처리구(1.85 mM 이상)에서는 $9.0%{\sim}12.4%$였다. 2% 물한천 배지에서의 농도시험에서는 발아율이 $1.1%{\sim}2.0%$로 일정한 경향을 나타내지 않았다. 규산칼륨을 17 mM의 농도로 희석하여 엽면살포한 결과 무처리에 비하여 흰가루병 발생이 현저히 억제되었으며, 방제효과 지속기간은 병원균 접종후 4일까지였다.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1158-1162
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• 2006

The glyoxylate cycle can conserve carbons and adequately supply tricarboxylic acid (TCA) cycle intermediates for biosynthesis when microorganisms grow on $C_{2}$ carbon sources. It has been reported that isocitrate lyase (ICL1), a key enzyme of the glyoxylate cycle, is highly induced when Magnaporthe grisea, the causal agent of rice blast, infects its host. Therefore, the glyoxylate cycle is considered as a new target for antifungal agents. A 1.6-kb DNA fragment encoding the ICL1 from M. grisea KJ201 was amplified by PCR, cloned into a vector providing His-tag at the N-terminus, expressed in Escherichia coli, and purified using Ni-NTA affinity chromatography. The molecular mass of the purified ICL1 was approximately 60 kDa, as determined by SDS-PAGE. The ICL1 inhibitory effects of TCA cycle intermediates and their analogs were investigated. Among them, 3-nitropropionate was found to be the strongest inhibitor with an $IC_{50}$ value of $11.0{\mu}g/ml$. 3-Nitropropionate inhibited the appressorium development in M. grisea at the ${\mu}M$ level, whereas conidia germination remained unaffected. This compound also inhibited the mycelial growth of the fungus on minimal medium containing acetate as a $C_{2}$ carbon source. These results suggest that ICL1 plays a crucial role in appressorium formation of M. grisea and is a new target for the control of phytopathogenic fungal infection.

• Journal of Microbiology
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• 제37권1호
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• pp.27-34
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• 1999

Two fractions with unusual antifungal activity that suppress asexual sporulation of several fungi were obtained from culture filtrate of Pseudomonas aeruginosa and were partially purified through the repeated silicagel flash column chromatographies. The sporulation-suppressive actions of these fractions in Aspergillus nidulans, Rhizopus stolonifer, and Coprinus cinereus, were analyzed by light and electron microscopes. The germination ability of the spores produced in the presence of these fractions were also checked to determine the persistent effects of these antifungal substances on the next generation. Light microscopic observation of developing sporangia of R. stolonifer grown in the presence of both fractions revealed that the significant number of sporangia failed to reach maturity, and frequently, uncontrolled growths of hyphae and rhizoids from the sporangiophores were found. In A. nidulans addition of these fractions appeared to cause different classes of morphological abnormality in conidia development, which included aborted formation of conidiogenous cells from the apex of conidiophores and enhanced hyphal growths either at the tip or middle of the conidiophores. Germination abilities of spores obtained from the cultures grown in the presence of antifungal fractions were 40∼60% in Aspergillus, 50∼80% in Coprinus (thallic spores), and 30∼40% in Rhizopus compared to those of normal spores.