• The Plant Pathology Journal
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• 제39권6호
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• pp.600-613
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• 2023

Fusarium oxysporum is the main pathogen causing Fusarium basal rot in onion (Allium cepa L.), which incurs significant yield losses before and after harvest. Among management strategies, biological control is an environmentally safe and sustainable alternative to chemical control. In this study, we isolated and screened bacteria for antifungal activity against the basal rot pathogen F. oxysporum. Isolates 23-045, 23-046, 23-052, 23-055, and 23-056 significantly inhibited F. oxysporum mycelial growth and conidial germination. Isolates 23-045, 23-046, 23-052, and 23-056 suppressed the development of Fusarium basal rot in both onion seedlings and bulbs in pot and spray inoculation assays. Isolate 23-055 was effective in onion seedlings but exhibited weak inhibitory effect on onion bulbs. Based on analyses of the 16S rRNA and rpoB gene sequences together with morphological analysis, isolates 23-045, 23-046, 23-052, and 23-055 were identified as Bacillus thuringiensis, and isolate 23-056 as Bacillus toyonensis. All five bacterial isolates exhibited cellulolytic, proteolytic, and phosphate-solubilizing activity, which may contribute to their antagonistic activity against onion basal rot disease. Taken together B. thuringiensis 23-045, 23-046, 23-052, and 23-055 and B. toyonensis 23-056 have potential for the biological control of Fusarium basal rot in onion.

• Mycobiology
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• 제51권4호
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• pp.264-272
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• 2023

Onion (Allium cepa L.) is an economically important vegetable crop worldwide. However, various fungal diseases, including Fusarium basal rot (FBR), neck rot, and white rot, reduce onion production or bulb storage life. FBR caused by Fusarium species is among the most destructive onion diseases. In this study, we identified Fusarium species associated with FBR in Jeolla and Gyeongsang Provinces in South Korea and evaluated fungicides against the pathogens. Our morphological and molecular analyses showed that FBR in onions is associated with Fusarium commune, Fusarium oxysporum, and Fusarium proliferatum. We selected seven fungicides (fludioxonil, hexaconazole, mandestrobin, penthiopyrad, prochloraz-manganese, pydiflumetofen, and tebuconazole) and evaluated their inhibitory effects on mycelial growth of the pathogens at three different concentrations (0.01, 0.1, and 1 mg/mL). We found that prochloraz-manganese was highly effective, inhibiting 100% of the mycelial growth of the pathogens at all concentrations, followed by tebuconazole. Fludioxonil showed < 50% inhibition at 1 mg/mL for the tested isolates.

• 한국식물병리학회지
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• 제14권5호
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• pp.463-466
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• 1998

A Fusarium species was isolated from stems of cactus(Hylocereus trigonus) showing rot symptoms at Koyang, Kyonggi province in 1997. This pathogen was identified as Fusarium oxysporum based on mycological characteristics. The rot symptom appeared at the soil line and roughly circular lesions, 1∼3 mm in diameter, appeared on basal stems. The pathogen formed both microconidia and macroconidia. Microconidia were formed abundantly in false-heads on short monophialides, oval to kidney-shaped. Macroconidia were slightly sickle-shaped, 3∼5-septated with an attenuated apical cell and a foot-shaped basal cell. Colony color on PDA was white, peach or purple. Chlamydospores were formed abundantly on PDA. The pathogen was able to cause stem rot symptoms to cactus by wound inoculation as well as non-wound inoculation.

• The Plant Pathology Journal
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• 제18권4호
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• pp.225-227
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• 2002

Moth orchid plants with yellowing blight and root rot symptoms were collected, and a total of 54 isolates of Fusarium spp. was obtained from roots and leaf bases of the diseased plants. The isolates were identified based on their morphological characteristics. Out of the 54 isolates of Fusarium spp., 42 isolates were identified as F. solani, 5 isolates as F. oxysporum, and 7 as F. proliferatum. Isolates of the three Fusarium spp. were tested for pathogenicity to moth orchid plants by artificial inoculation. All the Fusarium spp. induced root rot of the host plants. The symptoms progressed up to the basal part of the leaves, which later caused yellowing blight. The symptoms induced on the plants by artificial inoculation with the Fusarium spp. isolates were similar to those observed in greenhouses. The present study reveals that F. oxysporum, F. proliferatum, and F. solani cause root rot of moth orchid, and that F. solani is the main pathogen of the disease.

• The Plant Pathology Journal
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• 제18권3호
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• pp.156-160
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• 2002

Cymbidium orchids with blight and rot symptoms were collected, and a total of 63 isolates of Fusarium app. was obtained from pseudobulbs, roots, and leaves of the diseased plants. The isolates were identified based on their morphological characteristics. Out of the 63 isolates of Fusatium sup., 51 isolates were identified as F. oxysporum, 10 isolates as F. solani, and the rest as F. proliferatum. F. oxysporum was isolated from all the Cymbidium spp., while F. solani and F. proliferatum were isolated only from Cymbidium ensifolium and C. ginatum, respectively. Isolates of the three Fusarium spp. were tested for pathogenicity to their hosts by artificial inoculation. The strongly pathogenic isolates of Fusarium spp. induced severe dry rot of pseudobulbs and roots of the host plants. The symptoms progressed up to the basal part of the leaves, which later caused blight of the entire plant. The dry root symptoms induced on the plants by artificial inoculation with the isolates of Fusarium app. were similar to those observed in the growers'greenhouses. This is the first report of dry rot of Cymbidium spp. caused by F. oxysporum, F. solani, and F. proliferatum in Korea.

• 식물병연구
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• 제13권1호
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• pp.6-14
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• 2007

2005년과 2006년에 걸쳐 경기도 남양주의 호접란(Phalaenopsis spp.), 풍란(Neofinetia falcata), 나도풍란(Aerides japonicum)을 재배하고 있는 온실재배농가에서 뿌리 및 줄기기부 썩음 증상이 발생되었다. 이들 난은 초기에는 시들음 증상을 나타내고 병든 개체의 잎들은 황화되거나 붉게 변하며 낙엽되고 결국 고사하였다. 병든 개체의 뿌리 및 하엽으로부터 59개 Furaium spp.를 분리하여 동정 한 결과 F. oxysporum, F. proliferatum, F. solani 3종으로 동정되었다. 이 중 F. oxysporum, F. proliferatum은 호접란과 풍란류에서 모두 분리되었고, F. solani는 호접란에서만 분리되었다. 병원성실험 결과 이들 3종 모두 병원성이 인정되었다. 비록 F. oxysporum, F. proliferatum, F. solani은 호접란에 대하여 뿌리썩음병원균으로 보고되어 있으나 풍란과 나도풍란에 대해서는 아직 보고된 바 없다. 따라서 본 연구를 통해 F. oxysporum, F. proliferatum에 의한 풍란과 나도풍란의 뿌리 및 줄기썩음병을 처음 보고하는 바이다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2002년도 총회 및 추계학술발표회
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• pp.50.2-50
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• 2002

• The Plant Pathology Journal
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• 제28권1호
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• pp.49-54
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• 2012

In August 2010, a severe crown rot was observed on chrysanthemum ($Chrysanthemum$ $morifolium$ Ramat., variety Sinro) in several greenhouses located at Damyang and Muan, Jeonnam province, Korea. Three isolates (EML-CHS1, -CHS2, and -CHS3) of $Fusarium$ were isolated from the affected plants and identified based on morphological characteristics and rDNA internal transcribed spacer (ITS) sequence analysis. Sequence analysis by BLAST indicated that EMLCHS1, -CHS2 and CHS3 were closest to a $Fusarium$ species, $F.$ $solani$ with > 99% sequence similarity. Pathogenicity tests were performed on chrysanthemum with spore suspensions containing $3.4{\times}10^6$ spores/ml using the dipping method. Ten days after inoculation, similar symptoms to those observed in the greenhouses were seen on the inoculated plants. The causal fungus was reisolated from the artificially inoculated basal stems, fulfilling Koch's postulates. To our knowledge, this is the first report of crown rot by $Fusarium$ $solani$ on chrysanthemum ($Chrysanthemum$ $morifolium$) in Korea.

• 한국균학회지
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• 제45권1호
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• pp.74-82
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• 2017

꽃도라지(Eustoma grandiflorum)는 국내에서 장식용 화훼류로 널리 이용되는 절화류이다. 2015년 경기도 여주와 경남 김해 지역에서 꽃도라지가 시들고, 지제부가 잘록해지면서 위축되고, 뿌리가 썩는 증상이 나타났다. 병든 식물체는 포장이나 육묘상자에서 황화되고, 뿌리 발육이 저해되었고, 진전되면 전체적으로 황화되면서 시들고, 위축되며, 결국 2~3개월 안에 완전히 말라 죽는다. 병든 식물체 지제부에서 Fusarium균이 분리되었고, 9개 균주를 단포자 분리하여 형태적 특성을 조사한 결과, Fusarium solani로 동정되었다. 대형포자는 통통하고, 직선형이거나 약간 굽은 초승달 모양이고, 소형분생포자는 긴mono형태의 분생포자원세포에서 false head상으로 형성되었다. 후벽포자는 균사 중간 혹은 끝부분에 풍부하게 형성되었다. 이와 같은 동정 결과는 translation elongation factor 1 alpha (TEF)와 RNA polymerase II subunit (RPB2) 유전자의 염기서열 분석으로 재확인되었다. 그 결과, 분리 균주는 NCBI GenBank에 등록된 F. solani와 TEF 유전자는 99.2~99.9%, RPB2 유전자는 98.0~98.1%의 상동성을 나타내었다. 건전한 꽃도라지 유묘의 뿌리를 포자현탁액에 침지 접종하여 병원성 검정을 수행한 결과, 접종 7일 이내에 접종한 식물체에서만 병징이 관찰되었다. 따라서 이 병을 F. solani에 의한 꽃도라지 뿌리썩음병으로 명명하며, 병의 발생을 국내에서 처음으로 보고한다.

• The Plant Pathology Journal
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• 제26권3호
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• pp.216-222
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• 2010

Fusarium proliferatum is the causal agent of stalk and root rot disease of maize, foot rot disease of rice, basal and root rot disease of onion and knife cut disease of sugarcane in Iran. In recent years, incidence and severity of these diseases have been increased in Iran. Fifty seven F. proliferatum single-spore isolates collected from diseased maize, rice, onion and sugarcane plants at different areas were used to study genetic diversity by determination of vegetative compatibility groups (VCGs). Chlorate-resistant nitrate non-utilizing (nit) mutants were recovered from selected isolates of F. proliferatum and used in complementation tests. All isolates in which both nit1 and NitM (or nit3) mutants were recovered, demonstrated self-compatibility. Vegetative compatibility tests by pairing nit mutants identified 30 VCGs among 57 isolates. Twenty-three isolates belonged to singlemember VCGs and the remaining 34 isolates, belonged to other seven multimember VCGs. Segregation of F. proliferatum isolates obtained from various area and host plants into different VCGs in Iran is reported for the first time. In this study, none of isolates obtained from rice complemented with any other isolates from onion and sugarcane and, non complementation occurred between onion and sugarcane isolates. Also, only one complementation occurred between one isolate of maize and one isolate of sugarcane and rice. Thus, a correlation between VCGs grouping and host preferences was founded. It is concluded that natural populations of F. proliferatum in Iran are probably genetically divergent and include isolates representing a potential risk for disease development.