• The Plant Pathology Journal
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• 제18권1호
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• pp.43-49
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• 2002

Direct effects of atmospheric ozone on conidia of the rice blast pathogen, Magnaporthe grisea, were investigated to evaluate ozone-induced effects on infection potential of the rice blast fungus. Acute ozone exposure (200 nl $1^{-1}$, 8 h $day^{-1}$3 days) during sporulation significantly affected conidial morphology, appressorium formation, and disease development on rice loaves. Ozone caused reduction in conidial size and change in conidial shape. Relative cytoplasmic volume of lipids and vacuoles were increased in ozone-exposed conidia. Inhibition of appressorium formation and simultaneous increase in endogenous levee of polyamines were found in ozone-exposed conidia. The inverse relationship between appressorium formation and level of polyamines implies that ozone-mediated increase in intracellular level of polyamines may inhibit appressorium formation in rice blast fungus. Furthermore, rice plants inoculated with ozone-fumigated conidia exhibited less severe disease development than those with unfumigated conidia. This result suggests that the anti-conidial consequence of acute ozone will eventually weaken the rice blasts potential for multiple infection cycle. This further suggests that consequently, rice blast can be transformed from an explosive disease to one that has limited epidemiological potential in the field.

• 한국균학회지
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• 제50권3호
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• pp.183-194
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• 2022

Two fungal strains, designated KNUF-21-006 and KNUF-21-028, were isolated from soil samples collected from Gyeongbuk Province, Korea. The strain KNUF-21-006 was similar to other Pestalotiopsis species in terms of morphological characteristics, including whitish to pale brown mycelium, conidial shape, and size. The isolate had aerial hyphae that produced black fruiting bodies on the mycelium. The conidia were fusoid to ellipsoid, four-septate, and appendage-bearing. Phylogenetic analysis using the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (TEF), and β-tubulin (TUB) gene sequences confirmed that the closest relationship of the isolate at the species level was with Pestalotiopsis clavata. The strain KNUF-21-028 exhibits similar morphological characteristics to other Botryotrichum species, including white aerial mycelium with sulcate and irregular margins, conidial shape, and size. The conidia were globose, single, and hyaline. Upon molecular analysis-using the ITS region, large subunit (LSU) rRNA gene, and TUB gene sequences-the fungus was identified as Botryotrichum iranicum. This is the first record of these fungal species in Korea.

• 한국균학회지
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• 제20권4호
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• pp.309-314
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• 1992

분생포자 형성 양식에 따라 3 대별된 흰가루병균을 각각 3 종씩 총 9 종을 대상으로 1991년 5월부터 11월까지 채집하였다. 그 중 양지꽃 횐가루병균(Sphaerotheca aphanis), 왕고들빼기 흰가루병균(S. fusca), 장미 흰가루병균(S. Pannosa)은 기온의 변화에 무관하게 년중 분생포자 크기가 비슷하였으며, 장폭비도 뚜렷한 변화 양상을 나타내지 않았다. 쑥 흰가루병균(Erysiphe artemisiae)과 질경이 횐가루병균(E. sordida)은 기온이 상승함에 따라 분생포자의 장폭비가 증가하였으며, 돼지풀 흰가루병균(E. cichoracearum)은 기온이 하강할수록 분생포자의 장폭비가 증가하였다. 댕댕이덩굴 흰가루병균(Microsphaera pseudolonicerae)은 기온의 하강에 따라 분생포자의 폭이 감소하였으며, 이에 따라 장폭비가 크게 증가하였다. 이러한 경향의 변화는 본 연구에서 처음으로 확인되었다. 그리고 갈참나무 흰가루병균(M. alphitoides)과 아까시나무 흰가루병균(M. robiniae)은 기온의 변화와 무관하게 분생포자 측정치의 변화가 심했다. 특히 댕댕이덩굴 흰가루병균은 기온의 영향으로 가장 뚜렷한 변화를 나타냈으므로 앞으로 이 연구의 좋은 소재로 판단된다.

• The Plant Pathology Journal
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• 제32권5호
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• pp.388-395
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• 2016

The most serious aerial disease of garlic is leaf blight caused by Stemphylium spp. Geographical variation in the causal agent of this disease is indicated. Stemphylium vesicarium has been reported in Spain, whereas S. solani is the most prevalent species recorded in China. In this study, Stemphylium isolates were obtained from symptomatic garlic plants sampled from the main Spanish production areas. Sequence data for the ITS1-5.8S-ITS2 region enabled assignation of the isolates to the Pleospora herbarum complex and clearly distinguished the isolates from S. solani. Conidial morphology of the isolates corresponded to that of S. vesicarium and clearly discriminated them from S. alfalfae and S. herbarum on the basis of the size and septation pattern of mature conidia. Conidial morphology as well as conidial length, width and length:width ratio also allowed the Spanish isolates to be distinguished from S. botryosum and S. herbarum. Control of leaf blight of garlic is not well established. Few studies are available regarding the effectiveness of chemical treatments to reduce Stemphylium spp. incidence on garlic. The effectiveness of nine fungicides of different chemical groups to reduce Stemphylium mycelial growth in vitro was tested. Boscalid + pyraclostrobin (group name, succinate dehydrogenase inhibitors + quinone outside inhibitors), iprodione (dicar-boximide), and prochloraz (demethylation inhibitors) were highly effective at reducing mycelial growth in S. vesicarium with $EC_{50}$ values less than 5 ppm. In general, the effectiveness of the fungicide was enhanced with increasing dosage.

• Mycobiology
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• 제46권2호
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• pp.172-176
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• 2018

A new species belonging to the genus Alternaria was isolated from the necrotic leaf spots of Brassica rapa subsp. pekinensis in Yuseong district, Daejeon, Korea. It is an occasional isolate, not an etiological agent, which is morphologically similar to A. broccoli-italicae, but differs in conidial size and conidiophore shape. Phylogenetic analysis using the sequence datasets of the internal transcribed spacer (ITS) region of the rDNA, glyceraldehyde-3-phosphate dehydrogenase (gpd), and plasma membrane ATPase genes showed that it is distantly related to A. broccoli-italicae and closely related to Alternaria species in the section Pseudoalternaria, which belonged to a clade basal to the section Infectoriae. Morphologically, the species is unique because it produces solitary conidia or conidial chains (two units), unlike the four members in the section Pseudoalternaria that produce conidia as short branched chains. It exhibits weak pathogenicity in the host plant. This report includes the description and illustration of A. brassicifolii as a new species.

• 한국식물병리학회지
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• 제11권3호
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• pp.282-284
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• 1995

Grey leaf spot on tomato plants was first observed in Sedo-myeon, Puyo-kun, Chungnam province of Korea in 1994. This disease which had not been reported before in Korea exhibited different symptoms from those of other leaf spot diseases on tomato plants. The symptoms were characterized by small irregular-shaped spots on leaves at the initial stage of the infection, subsequent spread and coalescence of the spots throughout the leaves with ultimate necrosis, and abscission from the plants. When healthy tomato plants were inoculated with a conidial suspension of the fungus isolated from the lesion of a diseased plant in a field, the same characteristic symptoms as those in the field were produced. Furthermore, the same pathogen could be reisolated from the lesions formed buy the inoculation. Conidial characteristics of the pathogen were as follows; oblong shape with constricted 3 transverse septa, round-shaped base, round- or point-shaped apex, size of 45~75$\times$12.5~17.5 ${\mu}{\textrm}{m}$, and 3.5 : 1 ratio of length to width. The pathogen was identified as Stemphylium lycopersici and thus this is the first report on the occurrence of grey leaf spot disease on tomato plants caused by s. lycopersici in Korea.

• 한국균학회지
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• 제48권3호
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• pp.187-195
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• 2020

Two unreported fungal isolates, KNU-GW1901 and KNU-AP100C, were collected from soil sample in Gyeongsangbuk-do, Korea. Their cultural and morphological characteristics were examined after 4 weeks of incubation at 25℃ on potato dextrose agar (PDA), malt extract agar (MEA), and oatmeal agar (OA). The conidial shape of KNU-GW1901 was aseptate, hyaline, globose to ellipsoidal, oblong, and reniform to pyriform and 2.61-4.97×1.93-3.61 ㎛ in size, whereas no conidial structures were observed in KNU-AP100C. The internal transcribed spacer (ITS) regions, large subunit (LSU), and small subunit (SSU) sequences were used to determine the taxonomic positions of the strains using the maximum likelihood phylogenetic tree. The isolate KNU-GW1901 was closely clustered with Plenodomus sinensis MFLUCC 17-0767, and KNU-AP100C was closely matched with P. collinsoniae CBS 120227. Based on the findings of morphological, cultural, and phylogenetic analysis, the isolates KNU-GW1901 and KNU-AP100C were identical to the previously described P. sinensis and P. collinsoniae isolates, respectively, which are first reported in Korea.

• 한국미생물·생명공학회지
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• 제18권5호
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• pp.460-465
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• 1990

Asp.wentii와 Asp.nidulans의 원형질체 재생은 2-DG가 30$\mu g$/ml 첨가된 포자현탁액을 4시간 전배양 할 때 적당하였고 ergosterol, myoniositol, casamino acid, BSA가 함유된 CBE 재생용 배지에서 효과적이었으며, 30 이상 재생률을 나타내었다. 원형질체 융합은 10mM $CaCl_2$가 함유된 pH7.5의 30PEG 4000으로$37^{\circ}C$ 에서 10분간 처리했을 때 가장 양호하였으며, 융합빈도는 $8.2\times 10^{-4}$을 나타내었다. 가장 우수한 융합주인 FWN-56은 CMCase, avicelase, $\beta$-glucosidase 및 xylanase를 동시에 분비하였으며 친주에 비하여 활성이 2.3배, 1.5배, 1.8배, 2.5배 각각 증가하였고, 또한 MM에 4중 이상 보관 후의 segregant율이 1 이내였으므로 유전적 안정성은 높았으며, 분생포자 DNA함량은 1.4-1.6배였다. 또한 핵의 크기도 친주에 비하여 큰 것으로 보아 융합주임을 확인하였다.

• 한국균학회지
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• 제25권1호통권80호
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• pp.30-34
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• 1997

온주밀감의 병든 잎으로부터 분리된 분생포자세대와 병들어 죽은 가지로부터 분리된 유성세대의 형태학적 특정을 토대로 감귤 탄저병의 병원균은 Glomerella cingulata(분생포자 세대 Colletotrichum gloeosporioides)로 분리 동정되었다. 감귤 탄저병균은 온주밀감, 유자, 하귤 등의 잎에 상처 접종에 의해서 감염을 일으켰고, 균사 생장 및 분생포자 형성의 적온은 각각 $25{\sim}30^{\circ}C$범위였다. 잎과 가지에서 분리된 감귤 탄저병균의 균총의 생장 속도와 색, 분생포자와 부착기의 형태와 크기 등과 같은 특징들은 감귤류 저장병에 관여하는 FGG strain의 특징과 유사하였지만, 일부 형태 및 병원학적 특징이 FGG strain과 일치하지 않아 다른 strain일 가능성도 배제할 수 없다.

• The Plant Pathology Journal
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• 제33권2호
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• pp.109-117
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• 2017

Tan spot caused by the fungus Pyrenophora triticir-repentis is a serious disease of wheat, which is on increase in recent years in Mediterranean region. In the field this fungus produces a diamond-shaped necrotic lesions with a yellow halo on wheat foliage. The objective of this study was to characterize and compare several monospore isolates of P. tritici-repentis collected from different infected wheat fields in various locations of Algeria, and find the morphological differences between them, if any. The results revealed wide morphologically variation among the isolates based on colony colors and texture, mycelial radial growth and conidial size.