• 식물병연구
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• 제27권2호
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• pp.49-60
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• 2021

Cashew (Anacardium occidentale L.) is an important cash crop in Tanzania as a source of income to cashew growers and provides foreign exchange for the country. Despite its significance, the crop is threatened by fast spreading disease known as cashew Fusarium wilt caused by Fusarium oxysporum. Field assessment and laboratory tests were conducted to determine incidences of the disease, severity, ecological factors that influence them and explored the pathogen host specificity in six cashew growing districts. The results revealed significant (P<0.001) variation of disease incidences and severity among the studied districts. The results further revealed that there is both positive and negative correlation between the incidence and severity of the disease versus the evaluated ecological factors. The soil pH, soil temperature, air temperature, and relative humidity depicted positive correlation of disease incidence and severity versus ecological factors at ρ=0.50 and ρ=0.60, ρ=0.20 and ρ=0.94, ρ=0.11 and ρ=0.812, ρ=0.05 and ρ=0.771 respectively while nitrogen, phosphorus, and carbon depicted negative correlations at ρ=-0.22 and ρ=-0.58, ρ=-0.15 and ρ=-0.94, ρ=-0.19 and ρ=-0.12 respectively. In terms of host range, none of the weed species was found to be a carrier of Fusarium pathogen implying that it is host specific or semi selective. The results revealed that the tested ecological parameters favor the growth and development of Fusarium pathogen. Thus, management of the disease requires nutrients replenishment and soil shading as essential components in developing appropriate strategies for the control and prevention of further spread of the disease.

• The Plant Pathology Journal
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• 제38권3호
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• pp.229-238
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• 2022

Fusarium wilt caused by Fusarium oxysporum f. sp. niveum (Fon) is the most serious soil-borne disease in the world and has become the main limiting factor of watermelon production. Reliable and quick detection and quantification of Fon are essential in the early stages of infection for control of watermelon Fusarium wilt. Traditional detection and identification tests are laborious and cannot efficiently quantify Fon isolates. In this work, a real-time polymerase chain reaction (PCR) assay has been described to accurately identify and quantify Fon in watermelon plants and soil. The FONRT-18 specific primer set which was designed based on identified specific sequence amplified a specific 172 bp band from Fon and no amplification from the other formae speciales of Fusarium oxysporum tested. The detection limits with primers were 1.26 pg/µl genomic DNA of Fon, 0.2 pg/ng total plant DNA in inoculated plant, and 50 conidia/g soil. The PCR assay could also evaluate the relationships between the disease index and Fon DNA quantity in watermelon plants and soil. The assay was further used to estimate the Fon content in soil after disinfection with CaCN₂. The real-time PCR method is rapid, accurate and reliable for monitoring and quantification analysis of Fon in watermelon plants and soil. It can be applied to the study of disease diagnosis, plant-pathogen interactions, and effective management.

• 식물병연구
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• 제26권2호
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• pp.79-87
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• 2020

Fusarium oxysporum f. sp. fragariae (Fof) 에 의한 딸기 시들음병은 국내 딸기재배에서 가장 중요한 병해 중 하나이다. 국내 발생하는 Fof의 특성을 분석하고자 시들음병균의 유전적 다양성, 병원성과 살균제 반응을 조사하였다. 분리균은 Fo080701를 제외한 모든 균주에서 Fof 특이적 primer에 증폭되었다. 분리균의 nuclear ribosomal intergenic spacer region과 EF-1α sequences 분석 결과 3개의 lineage를 형성하였다. 대부분의 분리균은 lineage 1에 속하였으며 lineage 3에 3개 균주와 lineage 2에 1개 균주가 포함되었다. 분리된 모든 균주는 설향품종에 병원성을 보였다. Prochloraz는 DNA lineage 2에 속하는 Fo080701균주를 제외하곤 시들음병균의 EC₅₀값이 0.02-0.1 ㎍/ml로 낮은 농도에서 효과적으로 균사 생장을 억제하였다. Metconazole의 EC₅₀값도 0.04-0.22 ㎍/ml로 prochloraz와 비슷한 억제 효과를 보였다. Pyraclostrobin의 EC₅₀값은 0.23-168.01 ㎍/ml로 균주에 따라 차이가 컸다. 딸기 재배포장에서 boscalid+fludioxonil, fluxapyroxad+pyraclostrobin, prochloraz manganese이 딸기 시들음병 방제에 효과적이었다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 춘계학술대회 및 임시총회
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• pp.54-54
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• 2015

Crops lack genetic resistance to most necrotrophic soil-borne pathogens and parasitic nematodes that are ubiquitous in agroecosystems worldwide. To overcome this disadvantage, plants recruit and nurture specific group of antagonistic microorganisms from the soil microbiome to defend their roots against pathogens and other pests. The best example of this microbe-based defense of roots is observed in disease-suppressive soils in which the suppressiveness is induced by continuously growing crops that are susceptible to a pathogen. Suppressive soils occur globally yet the microbial basis of most is still poorly described. Fusarium wilt, caused by Fusarium oxysporum f. sp. fragariae is a major disease of strawberry and is naturally suppressed in Korean fields that have undergone continuous strawberry monoculture. Here we show that members of the genus Streptomyces are the specific bacterial components of the microbiome responsible for the suppressiveness that controls Fusarium wilt of strawberry. Furthermore, genome sequencing revealed that Streptomyces griseus, which produces a novel thiopetide antibiotic, is the principal species involved in the suppressiveness. Finally, chemical-genetic studies demonstrated that S. griseus antagonizes F. oxysporum by interfering with fungal cell wall synthesis. An attack by F. oxysporum initiates a defensive "cry for help" by strawberry root and the mustering of microbial defenses led by Streptomyces. These results provide a model for future studies to elucidate the basis of microbially-based defense systems and soil suppressiveness from the field to the molecular level.

• Journal of Microbiology and Biotechnology
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• 제14권1호
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• pp.212-215
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• 2004

In order to develop a biocontrol agent that can effectively control Fusarium wilt on Cymbidium genus, the effectiveness of antagonistic microbes against the cause pathogen was screened. The selected microbe showed a broad spectrum of antifungal activity, and the culture broth of this microbe had better preventive effect on Fusarium wilt than the commercial chemical agent in the pot assay. This isolated strain, GBA-12, was identified as Streptomyces kasugaensis, and the antifungal substance was purified from a broth culture of GBA-12. This purified substance was identified as a polyene macrolide (YS-822A) that was newly discovered from Streptomyces kasugaensis, and it exhibited antifungal activity against several phytopathogenic fungi.

• 한국식물병리학회지
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• 제11권4호
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• pp.324-329
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• 1995

Severe Fusarium wilt of tomato was observed in greenhouses in Sedo, chungnam and Sandae, Kyeongbuk from march to May 1993. Among the 20 isolates of Fusarium oxysporum isolated from wilted tomato plants and their rhisoplane or rhizosphere, 18 isolates were pathogenic to tomato. All of the pathogenic isolates were identified as F. oxysporum f. sp. lycopersici; they were pathogenic only to tomato and not pathogenic to red pepper, potato and egg-plant. The isolates of F. oxysporum f. sp. lycopersici used in this study could be divided into 2 races according to their pathogenicity to eight differential varieties of tomato. Of 10 isolates tested, 6 were classified as race 1, while 4, as race 2.

• The Plant Pathology Journal
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• 제17권6호
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• pp.363.3-363
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• 2001

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 정기총회 및 춘계 학술발표회
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• pp.29-29
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• 1999

• 한국응용곤충학회지
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• 제1권
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• pp.3-10
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• 1962

1) 강력한 위조독소(Wilt toxin)인 Fusaric acid를 생성하는 것으로 알려진 참깨$\cdot$시들음병균(Fusarium oxysporum f. vasinfectum)의 배양여액이 참깨의 종자발아 및 발아후의 유식물의 생육에 미치는 영향을 구명하기 위하여 이 시험연구에 착수하였다. 2) Fusarium oxysporum f. vasinfectum의 5종의 계통의 배양여액은 모두 참깨종자의 발아를 억제하고 종자의 흑변, 괴사를 초래한다. 3) 공시균의 어떤 계통의 배양여액에 대한 참깨종자의 발아반응에 있어서의 품종간 차이는 없다. 4) 공시균의 5종의 계통의 배양여액이 참깨종자의 발아를 억제하는 독성에는 뚜렷한 차이가 있다. 5) 공시균의 5종의 계통의 배양여액을 첨가한 육묘상에서는 발아후의 참깨유식물의 뿌리나 줄기의 신장이 다 같이 억제되며 조직은 흑변, 괴사하게 된다. 그러나 배양여액을 $10\%$ 첨가한 육묘상에서는 줄기의 신장생장 약간 촉진되는 경향이 있다. 6) 공시균의 배양여액을 $1\%$ 내지 $1\%$ 첨가한 Knop Solution에 본엽이 생기지 않은 참깨 유식물을 배양하면 참깨의 뿌리나 줄기의 신장생장이 억제되고 제2본엽이 전개할 때까지에 줄기나 잎자루나 연화, 흑변, 괴사하며 제1본엽에는 맥간에 염갈색반문이 형성되고 제2본엽은 권축, 흑변, 괴사하며 특히 제2본엽에 나타나는 병상은 포장에서 나타나는 참깨의 잎의 위조병징과 흡사하다. 7) 공시균의 5종의 계통간에 나타나는 배양여액의 독성의 차이는 공시균의 각계통자체의 기생에 의한 병원성의 차이와 일치하지 않는다

• 식물병연구
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• 제17권1호
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• pp.32-37
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• 2011

유기물, 석회질소, 요소 병행처리가 딸기 시들음병의 친환경적 방제인 태양열소독의 효과 증진여부를 밝히고자 논산딸기시험장의 비닐하우스에서 2006년과 2008년에 분석하였다. 딸기에서 분리한 Fusarium oxysporum f. sp. fragariae 7개 균주의 100% 치사시간은 $45^{\circ}C$에서 6.6일, $50^{\circ}C$에서는 5.1일이 소요되었고 100% 치사온도는 $46.7{\pm}0.1^{\circ}C$로 나타났다. 태양열 소독에 의해 유기물 처리구는 처리전보다 토양내 유기물 함량이 증가하였고, 석회질소 처리구는 산도, 유기물, 칼슘 함량이 증가하였으나 요소처리구는 차이가 없었다. 태양열 소독시 지온은 처리간에 차이를 나타냈으며 7월 30일부터 8월 10일까지가 가장 높았고($48.4\sim54.8^{\circ}C$) 유기물+석회질소 처리구가 다른 처리구보다 $3\sim4^{\circ}C$ 높게 유지되었다. 또한 토양내 시들음병균은 각 처리구 모두에서 사멸되었다. 시들음병 이병주율은 무처리는 2006년 20%, 2008년 13.3%의 발병율을 나타낸 반면 태양열 소독 처리구 모두에서는 시들음병 발생이 없었으며 처리간 유의성이 있었다. 따라서 딸기 시들음병 방제를 위한 유기물+석회질소를 병행한 태양열 소독 방법은 기존의 태양열소독방법을 보완하여 처리기간을 줄이면서도 효과적인 방법이 될 것이다.