• Parasites, Hosts and Diseases
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• 제22권2호
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• pp.253-258
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• 1984

Naegleria fowleri를 마우스 비강을 통하여 감염시킨 뒤 P.A.M. 발생율 및 발병후 생존기간을 마우스 주별 체중별, 성별, 접종아메 바수에 따라 비교하여 다음과 같은 성적을 얻었다. 1. N. fewleri를 감염시킨후 P.A.M. 발생은 ICR마우스보다 BALB/C마우스에서 많았으며 감염후 평균생존기간은 차이가 없었다. 2. 마우스 성별에 따른 N. fowleri감염후 P.A.M.발생율 및 발병후 평균생존기간은 차이가 없었다. 3. 체중이 다른 여러 실험군에서 P.A.M. 발생율 및 사망율은 차이가 없었으나 발병후 마우스의 평균생존 기간은 체중이 가벼운 실험군에서 짧았다. 4. 감염시킨 아메 바수에 따른 P.A.M. 발생율은 영양형 Ix104이상 감염 군에서는 차이가 없었으나 0.5x104인 경우 P.A.M 발생이 현저히 감소하였다.

• 한국식물병리학회지
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• 제1권3호
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• pp.173-177
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• 1985

본 연구는 자연이병된 오이와 호박 종자에서 분리한 덩굴마름병균(만고병균)의 병원성의 차이를 조사한 것이다. 오이, 참외, 호박 및 수박의 유묘에 대한 일차 감염은 유근$\cdot$배축$\cdot$자엽에 나타났으며 병징은 작물에 관계없이 비슷하였다. 유근이 병들었을때는 발아전 부패현상으로 나타났고 배축과 자엽의 감염은 제1엽과 줄기로 이어지는 접종원이었다. 교호접종시험 결과 공시된 덩굴마름병균의 모든 분리균은 오이, 참외, 호박, 수박의 종자 및 유묘에 대하여 병원성이 있었으나 분리균이나 공시작물간에는 차이가 별로 나타나지 않았다. 오이와 호박의 감수성은 다습조건에 의해서 크게 영향을 받았다.

• 한국연초학회지
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• 제11권1호
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• pp.41-48
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• 1989

The significance of soil and/or rhisosphere populations of Erwinia carotovora sobsp. carotovora (Ecc) as a source of primary inoculum for tobacco hollow stalk disease has been demonstrated conclusively. The survival of Ecc in field soils fter overwintering was estimated by using the enrichment technique. The population number of pectolytic erwinia (PE) in field soils relatively decreased at the rate of 102-104 colony forming unit(CFU) per g of soil after overwintering. Higher level of PE population overwintered in the rhlzosphere foils of tobacco stubbles and detected more frequently in rhizosphere soils of weed plants than in those of bare fields. All of the tobacco stubbles collected from fields where tobacco had been grown the previous year contained Ecc. The more survived population number of PE at the 30cm depth of artifitiany infested soils than at the upper of those by introducing with diseased tobacco plant tissue after overwintering. Ecc overwintered effectively in rhizosphere soils of tobacco stubbles, overwintered weeds and tobacco debris in field soils.

• The Plant Pathology Journal
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• 제27권1호
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• pp.20-25
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• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• The Plant Pathology Journal
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• 제31권3호
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• pp.245-251
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• 2015

Alternative hosts increase the difficulty of disease management in crops because these alternate hosts provide additional sources of primary inoculum or refuges for diversity in the pathogen gene pool. Agropyron cristatum (crested wheatgrass), Bromus inermis (smooth bromegrass), Pascopyrum smithii (western wheatgrass), Stipa viridula (green needlegrass), and Thinopyrum intermedium (intermediate wheatgrass), commonly identified in range, prairie, verge, and soil reclamation habitats, serve as additional hosts for Pyrenophora tritici-repentis, the cause of tan spot in wheat (Triticum aestivum L.). A. cristatum (five lines), B. inermis (seven lines), P. smithii (four lines), S. viridula (two lines), and T. intermedium (six lines) were tested for their reactions to 30 representative P. tritici-repentis isolates from races 1-5. Plants were grown until the two-three-leaf stage in a greenhouse, inoculated individually with the 30 isolates, held at high humidity for 24 h, and rated after 7 days. All lines developed lesion types 1-2 (resistant) based on a 1-5 rating scale. Also, leaves from an additional plant set were infiltrated with two host selective toxins, Ptr ToxA as a pure preparation and Ptr ToxB as a dilute crude culture filtrate. All lines were insensitive to the toxins. Results indicate that these grass hosts have a limited or nonsignificant role in tan spot epidemiology on wheat in the northern Great Plains. Additionally, the resistant reactions demonstrated by the grass species in this research indicate the presence of resistance genes that can be valuable to wheat breeding programs for improving wheat resistance to P. tritici-repentis.

• 한국응용곤충학회지
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• 제22권2호
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• pp.130-137
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• 1983

A wide variety of pathogens are known io be seedborne, carried either as infectious mycelium internally or as contaminants on the seed coat. When seed is infected with a pathogen, the seed nay be rendered nonviable or it may remain viable but produce weak seedling. In some cases, the Infected seedling nay not be severely weakened, but nay serve as a source of primary inoculum within a community of plants. A recent problem nay be the dissemination of seedborne pathogens occurring as a result of the massive movements of seed, as a part of the 'Green revolution' Disease of great danger to agriculture may be introduced with seed from other parts of world. Seed treatment with organic mercury compounds in liquid form had become popular since about 1955. Organic mercury compounds contributed considerably to the increase in production of many crops and vegetables. In 1975, however, the use of organic mercury compound was forbidden because of doubts regarding their residual mammalian toxicity in agricultural products. Benomyl-thiram mixture, thiophanate methyl-;hiram mixture and TCMB have now been registered as seed disinfectants for the use of rice blast, brown spot and Bakanae disease. Oxathiinsthiram mixture has been registered as seed disinfectant for barley and wheat loose smut and leaf stripe of barley. Agricultural techniques have made such rapid progress that the nursery methods changed from the use of paddy nursery to box nursery designed for machine-transplanting. The spread of rice transplanting machines has caused increase of seedborne diseases. Among seedborne diseases, Bakanae disease has remarkably increased and causes much damage recently. In order to counter this trend, seed disinfectants must also be diversified. First, effective non-selective disinfectants need to be developed, and second, appropriate control methods always need to be prepared in parallel with the development of new techniques for cultivation.

• 식물병연구
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• 제10권3호
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• pp.198-202
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• 2004

2001년∼2002년에 탄저병을 심하게 발병시킨 딸기 재배포장의 식물체 조직에서 탄저병균 Colletotrichum gloeosporioides와 Glomerella cingulata의 월동과 토양에서의 생존유무를 조사하였다 식물체의 엽병, 런너, 관부에서 월동 생존율은 각각 68.7％, 14.3％, 36.7％였다. 그러나 포장조건하에서 분생포자는 토양의 표면, 3, 5, 10cm 깊이에서 전혀 검출되지 않았다. C. gloeosporioides와 G. cingulata의 토양과 이병잔재물에서의 생존력을 비교 조사하기 위해 온도와 수분조건을 달리하여 처리한 다음 경시적으로 분리비율을 조사하였다. 분생포자는 모든 처리에서 10일 이내에 개체군이 40％까지 급격히 감소하였으며 시간이 지날수록 더욱 많이 사멸되었다. 토양 속에서 G. cingulata 분생포자의 생존율은 C. gloeosporioides와 비슷하였다. 분생포자의 생존율은 온도가 낮고 건조한 토양일수록 높았고 토양 온도와 습도가 증가할수록 감소하였다. 토양에 묻어둔 감염된 엽병분석에서도 유사한 경향을 나타내었다.

• 한국응용곤충학회지
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• 제11권1호
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• pp.31-35
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• 1972

밀, 보리 붉은곰팡이병균의 분생포자 및 자낭각형성에 미치는 광선의 영향을 수량적으로 연구하고, 분생포자의 제1차 전염원으로서의 가능성을 증명하기 위해서 토양에서의 일동상태를 조사하였다. 1. 균주 진주 1은 연속광선조사구에서는 광암교호구 및 암처리구보다 분생포자 형성이 많았다. 균주 수원 3은 암처리에서도 진주 1의 광처리보다 분생포자 형성이 많았으며, 광암교호구에서는 배양일 8일후 현저히 증가하였다. 2. 두 균주 모두 자낭각 형성에는 광선이 필요했고, 수원 3은 연속광선처리에서도 미숙 자낭각만을, 진주 1은 암처리를 제외한 다른 처리에서 많은 성숙자낭각 및 미숙자낭각을 형성했다. 분생포자 형성과 자낭각형성은 균주간에 차이가 있었고, 진주 1은 분생포자 형성량은 적으나, 자낭각형성은 많았고, 수인 3은 그와 반대였다. 3. 분생포자는 각각 $10,\; 30,\; 50\%$의 토양습도에서 겨울동안 그 수가 현저하게 감소했으나, 이듬해 3월부터 토양습도에 관계없이 그 수가 증가했다 즉 밀, 보리 붉은곰팡이병균의 분생포자는 토양에서 월동할 수 있었으며, 1차 전염원의 가능성이 있다고 본다.

• 식물병연구
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• 제8권2호
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• pp.120-123
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• 2002

고추 탄저병 발생 상황을 알아보기 위하여 경북 북부 지방의 예천, 안동, 의성, 청송, 영양, 봉화 등 6개 시군 고추 주산지에서 포장 조사한 결과, 본포에서 6월부터 발병이 시작되어 9월 중순에는 약 30%로 급증하였다. 고추 탄저병이 인접과실로 전염하는 데는 보통 2-3일이 소요되었으며, 5-7일 후에 만연되는 것을 확인할 수 있었다. 과실에 탄저병을 일으키는 병원균은 대부분 Colletotrichum gloeosporioides였다. 고추 탄저병 발생에 관여하는 요인은 무엇보다도 이병 잔재물과 연작에 의한 1차 전염원의 증가, 생육기의 강우일수와 그 지속기간 등 기상 요인들이 복합적으로 관여함을 알 수 있었다. 병 발생을 줄이기 위해서는 이병 잔재물의 월동전 처리와 타 작물과의 윤작, 비가림 재배, 예방 위주의 약제 살포가 필요하다고 본다.

• The Plant Pathology Journal
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• 제16권6호
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• pp.297-305
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• 2000

Weeds are widely grown in the field and are infected by many viruses. A survey was conducted to identify viruses infecting weeds in Korea. Virus-infected weed samples including Rorippa indica (L.) Hiern, R. islandica (Oed.) Bord, Crepidiastrum denticulatum (Houtt.) Pak & Kawanno, Achyranthes japonica (Miq.) Nakai, and Chrysanthemum boreale (Makino) Makino were collected in Kyonggi Province. These weeds were grown in the greenhouse and were isolated on 10 test plants. Several virus isolates were isolated fron infected tissues and were further studied by host range assay, serological test, electron microscopy (EM), reverse transcription-polymerase chain reaction (RT-PCR) and sequencing. Each isolated virus strain was mechanically transmitted to weeds and various hosts including Nicotiana spp., Brassica spp., Vigna unguiculata, Capsicum annuum, and Cucumis sativus and showed systemic mosaic, vein clearing, necrosis, mottle, malformation, chlorosis, and/or death of host plants in some cases. Each virus was then purified using infected leaves and observed by EM. From these results three viruses were isolated and identified as Turnip mosaic virus (TuMV), Broad bean wilt virus (BBWV), and Cucumber mosaic virus (CMV). RT-PCR using virus-specific oligonucleotide primers and the cloning were conducted to determine the nucleotide sequences of coat proteins of the three viruses their amino acid sequence were deduced. The amino acid sequence homologies were about 92.7 to 99.7%, 96.2 to 97.7%, and 93.9 to 98.6% to other reported TuMV, BBWV, and CMV strains, respectively. These results suggest that many weeds may serve as primary inoculum source of diseases caused by TuMV, BBWV, CMV and that the management of these viral diseases can be achieved through weed control.