• Mycobiology
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• 제35권4호
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• pp.230-234
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• 2007

In order to breed a Cordyceps bassiana isolate that stably forms fruiting body in artificial cultivation, isolates derived from subculturing and single spores were tested through mating. From C. bassiana EFCC 783, three subcultured isolates EFCC 2830, EFCC 2831 and EFCC 2832 were obtained and fourteen single conidial isolates were obtained from these three subcultured isolates. Two different morphological types were found in the fourteen single conidial isolates. One type was able to form synnemata and another type was not able to form synnemata. Since switch of morphological type was not observed despite their continuous subculturing, cross was performed between the two types and the formation of fruiting body was examined. Ascospores were obtained from a selected fruiting body formed by hybrid of the cross. Self-cross and combinational cross of the ascospore-derived isolates generated hybrids that stably produce high quality fruiting body in artificial media.

• Mycobiology
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• 제38권1호
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• pp.13-16
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• 2010

A specimen of Beauveria bassiana was collected from Yang-yang of Gangwon province, Korea in October 2006. Conidial isolates were prepared from the specimen by the dilution method and inoculated in brown rice medium for fruiting body production. After nearly two months incubation for perithecial stromata developed from single isolates as well as from their combinations. They were determined as Cordyceps bassiana by observing the stromatal characters and their conidial structures. This is the first report of the development of C. bassiana from B. bassiana cultures.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.112.3-113
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• 2003

More than 30 isolates of Alternaria were obtained from various solanaceous crops in Korea. For all isolates, morphological characteristics of the conidia were determined and compared with those of representative isolates of A. solani and A. tomatophila. Pathogenicity test was performed to Potato, tomato, egg plant and red Pepper and molecular characteristics of them including the representative isolates were determined using sequence analyses of ITS rDNA and histone H3 gene, and URP-PCR analysis. Based on morphological characteristics, the isolates from the solanaceous crops were grouped as identical or very similar to either A. tomatophila(ATO), A. solani(ASO), and unidentified Altemaria sp.(ASP). Among the molecular markers used in this study, the URP-PCR analysis was found to be appropriate for taxonomic resolution of these species. Based on the conidial morphology, pathogenicity test and molecular characteristics, A. tomatophila(early blight of tomato) could be distinguished from A. solani(early blight of potato), and the Alternaria sp.(ASP) from potato, which was closely related to A. solani in conidial morphology, was considered as a new species.

• 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.

• 식물병연구
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• 제29권2호
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• pp.130-136
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• 2023

Citrus melanoses caused by Diaporthe citri, has been one of the serious diseases in many citrus orchards of Jeju Island. To protect melanose in citrus farms, a fast and exact diagnosis method is necessary. In this study, diseased leaves and dieback twigs were collected from a total of 49 farms within March to April in 2022. A total of 465 fungal isolates were obtained from a total of 358 isolated plant samples. Among these fungal isolates, 40 representatives of D. citri isolates which were isolated from 22 twigs and 18 leaves on 23 farms were found based on cultural characteristics on potato dextrose agar and conidial morphology. Additionally, the molecular assay was carried out and compared with those by morphological diagnosis. All isolates were identified as D. citri by analyzing the sequences at the internal transcribed spacer (ITS) rDNA region using primers of ITS1/ITS4 or at β-tubulin using primer Btdcitri-F/R. Therefore, based on the present study, where the results of morphological identification of conidial type were consistent with DNA sequence analysis of certain gene, choosing a suitable method for a fast diagnosis of citrus melanose was suggested.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.96.2-97
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• 2003

More than 1200 microorganisms were isolated from soil samples collected from various sources and localities. Among the isolates, 2 actinomyces (TH-04 and BA313) and 1 Bacillus sp. (CJ3) were selected as antagonists to pepper anthracnose fungus Colletotrichum gloeosporioides. These 3 isolates inhibitied mycelial growth of C gloeosporioides and the inhibition rates were over 70％ on PDA. When the isolates were co-cultured with conidia of C. gloeosporioides in potato dextrose broth, conidial germination was severely inhibited and the inhibition rates of TH-04, BA313, and CJ3 at 24 hours were 75％, 72％, and 68％, respectively. The inhibition rates at n hours incubation were not much different from the rates at 24 hours. To check the activity on the plant, each isolate was mixed with equal volume of conidial suspension of C. gloeosporioides and wound-inoculated on green pepper fruit. After 6 days, the anthracnose lesions on the fruits inoculated with the mixture were much smaller than the lesions caused by the C. gloeosporioides itself. The lesion areas of TH-04 or BA313 treated pepper were less than 30％ of the check. TH-04 and BA313 also showed antagonistic activity to Phytophthora spp. and Botrytis cinerea. By scanning electron microscopy and fatty acid analyses (MIDI), TH-04 and BA313 were identified to Streptomyces halstedii and S. violaceusniger, repectively.

• 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.

• 한국균학회지
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• 제31권2호
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• pp.103-113
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• 2003

국내의 가지과 작물에서 분리한 Alternaria 25 균주를 공시하여 분생포자의 형태적 특징을 조사하였고 A. solani와 A. tomaotphilad의 대표균주와 비교하였다. 분리균주 중 형태적으로 구별되는 몇 균주들과 대표균주를 공시하여 감자, 토마토, 가지, 고추에 대한 병원성 검정을 실시하였다. 대표균주를 포함한 Alternaria 17개 균주를 공시하여 ITS 영역과 histone h3 유전자의 염기서열분석, URP (universal rice primer)에 의한 핵산지문분석을 실시하였다. Alternaria 균주들은 분생포자의 형태적 특징에 의하여 A. tomaotophila(ATO), A. solani(ASO) 및 미동정의 Alternaria sp.(ASP)의 group으로 나눌 수 있었고 A. solani(ASO)는 분생포자 부리(beak)의 특징에 의하여 다시 ASO(1)과 ASO(2)의 2 type으로 나눌 수 있었다. ATO와 ASO 균주들은 실험에 사용한 감자, 토마토, 가지, 고추에 모두 병원성이 있었고 ATO 균주는 특히 토마토에 강한 병원성이 있었으나, ASP 균주는 감자에만 병원성이 있었다. 이 연구에서 사용한 molecular marker중 ITS와 histon H3 유전자의 염기서열 분석은 4개의 형태적 group을 명확히 구분할 수 없었지만, URP-PCR 핵산지문분석법은 이들 group을 명확히 구분할 수 있었다. 분생포자의 형태, 병원성검정, 분자생물학적 특징을 종합할 때 토마토 겹무늬병에 관여하는 A. tomatophila는 감자겹둥근무늬병에 관여하는 A. solani와 뚜렷이 구분할 수 있었다. 또한 감자에서 분리한 Alternaria sp.(ASP)는 A. solani(ASO)와 형태적으로 유사하였지만 분생포자의 폭이 두껍고 부리(beak)가 작다는 점에서 ASO와 구별되었으며 가지과 작물에서 보고된 바 없는 신종으로 추정되었다.

• Mycobiology
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• 제45권3호
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• pp.220-225
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• 2017

Ginseng root rot caused by Cylindrocarpon destructans is the most destructive disease of ginseng. Six different fungicides (thiophanate-methyl, benomyl, prochloraz, mancozeb, azoxystrobin, and iprodione) were selected to evaluate the inhibitory effect on the mycelial growth and conidial germination of C. destructans isolates. Benomyl and prochloraz were found to be the most effective fungicides in inhibiting mycelial growth of all tested isolates, showing 64.7% to 100% inhibition at a concentration of $10{\mu}g/mL$, whereas thiophanate-methyl was the least effective fungicide, showing less than 50% inhibition even at a higher concentration of $100{\mu}g/mL$. The tested fungicides exhibited less than 20% inhibition of conidium germination at concentrations of 0.01, 0.1, and $1{\mu}g/mL$. However, the inhibition effect of mancozeb on condium germination of C. destructans was significantly increased to 92% to 99% at a higher concentration of $100{\mu}g/mL$, while the others still showed no higher than 30% inhibition.

• The Plant Pathology Journal
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• 제20권3호
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• pp.165-171
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• 2004

A total of 62 isolates of Bipolaris cactivora causing cactus stem rots were isolated from major cactus-growing areas in Korea. Colony morphology of the isolates on potato-dextrose agar was differentiated into aerial (CA) and non-aerial mycelial types (CB). CA had profound aerial mycelium with grayish brown (CA-l), light brownish (CA-2), and brownish (CA-3) pigmentations; respectively, while CB had dark brownish pigmentations. CA had conidia of less dark pigmentation and acute terminal end. CB had darker and more round-end conidia. Twenty-eight amplified fragments were produced by polymerase chain reaction (PCR) with a set of 2 random primers. The sizes of amplified DNA fragments ranged approximately from 0.1 to 2.3 kb. The isolates were classified into 2 major genomic DNA random amplified polymorphic DNA (RAPD) groups at the genomic similarity of 97.7％ and 95.1％, respectively. Cluster analysis of genetic similarity among the isolates generated a dendrogram that clearly separated all isolates into SA or SB. This result suggests that there may be two morphotypes of B. cactivora in Korea that may differ in their genetic constitutes.