• 한국식물병리학회지
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• 제14권2호
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• pp.184-185
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• 1998

Rhizoctonia stem rot of Saururui herba [Saururus chinensis (Lour) Baill] was observed during plantations from 1996 to 1997 in Chungbuk area. Infected plant showed damping-off and stem rot at soil line. The causal fungus of stem rot isolated from the infected plant was identified as Rhizoctonia solani according to the criteria based on the cultural and morphological characteristics. The stem rot of Saururi herba caused by Rhizoctonia solani was first described in Korea, and the name the“Rhizoctonia black stem rot”is proposed.

• 한국응용곤충학회지
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• 제21권3호
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• pp.128-132
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• 1982

봄보리 1.5엽기에 흰가루 병균을 접종하여 병진전에 따른 엽내전분함량변화를 측정하였다. 1.5엽기에 접종하였을 때 감수성 품종 Peruvian과 성체식물저항성 품종 Asse에서 상이한 전분축적양상을 보였다. 감염초기에서는 두 품종 모두 전분함량에 다소 변화가 있었다. 병반형성과 포자형성 동안 감수성 품종 Peruvian에서 전분함량감소가 뚜렷하였으나 Asse에서는 병반형성 동안 증가하였고 세포형성전후에 급격히 감소하였다. 감염이 심한 1.5엽에서 Peruvian은 급격한 전분감소를 보였으나 Asse는 감염강도에 관계없이 감염잎에 높은 전분함량을 유지하였다. 봄 보리의 성체식물저항성과 연관시켜 상이한 발육시기에서 흰가루병 감염된 잎의 전분축적역할을 논하였다.

• 한국식물병리학회지
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• 제3권1호
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• pp.3-7
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• 1987

도열병에 대해 감수성을 보이는 낙동과 성체식물저항성을 보이는 도봉의 건전엽과 도열병 감염엽내의 에탄올가용성 아미노산과 페놀화합물을 양적으로 분석하였다. 접종 3일후에는 가용성 아미노산과 페놀화합물의 수준은 건전엽과 비슷하였다. 도열병 병반이 접종 5일 후에 감염엽에 나타났을 때 가용성 아미노산과 페놀화합물은 5엽기와 3엽기에서 증가하기 시작하였고, 접종 7일 후에서는 이들 화합물의 수준은 5엽기와 8엽기에서 건전엽보다 약 $1.5\~3$배 더 많았다. 도열병 감염동안 비록 도봉이 도열병에 대해 낙동보다 덜 감염되었지만 5엽기와 8엽기의 건전엽과 감염엽에서 성체식물저항성 품종 도봉의 가용성 아미노산 및 페놀화합물 함량은 감수성 품종 낙농의 함량보다 높았다. 벼품종 도봉이 도열병에 감염동안 아미노산과 페놀화합물 함량이 현저하게 증가하여 성체식물저항성이 발현하는데 중요한 역할을 할지 모른다.

• Journal of Life Science
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• 제12권2호
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• pp.61-74
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• 2002

One of the major aims in studying plant viruses is to minimise the development of symptoms in infected plants. With the advent of in vitro transcript mediated research on plant viruses, substantial progress has been made. This article describes the biology of a plant specific RNA virus, Johnsongrass mosaic virus (JGMV), important to Australian sorghum and corn agriculture and, in particular, at a molecular level which of the RNA sequences in its genome that make it possible for the virus to move from cell to cell, and eventually spread systemically throughout the entire plant. The JGMV has caused considerable yield losses in maize and sorghum over a number of years in Australia. Incidents where 100% of the crop has been infected are on record. The use of this virus is convenient under laboratory conditions because it can be readily transmitted by mechanical inoculation with infected leaf sap, which obviates the need for maintaining aphid colonies. The JGMV is a single stranded positive sense RNA virus.

• The Plant Pathology Journal
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• 제16권4호
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• pp.216-221
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• 2000

Mixed infection of watermelon mosaic potyvirus II isolated from pumpkin (WMV-P) and cucumber green mottle mosaic tobamovirus from watermelon (CGMMV-W) caused extremely severe symptoms such as progressive silting and death of watermelon plants. Single infections of either WMV-P or CGMMV-W on the same hosts produced only vein clearing and/or mosaic on the upper leaves. In cells infected with WMV-P, potyvirus-characteristic inclusions of pinwheels, scrolls and cylindrical inclusions were present in the cytosol. Parallel arrays of virus particles in the tonoplast were also common. In cells infected with CGMMV-W, virus particles occurred as stacked-bands of scattered randomly in the cytosol and vacuoles in all type cells. Many cells also contained vesiculated mitochondria with fibril-containing vesicles. Cells infected mixedly with WMV-P and CGMMV-W contained structural features that were not observed in cells infected singly with the two viruses. A particle of WMV-P potyvirus was surrounded by evenly spaced nine particles of CGMMV-W tobamovirus, which made a unique nonagon ring. The angled layers having $60^{\circ}$-$135^{\circ}$ were alternating layer, herringbone, crosshatching and ladder figures.

• The Plant Pathology Journal
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• 제37권4호
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• pp.396-403
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• 2021

Fire blight disease, caused by Erwinia amylovora, could damage rosaceous plants such as apples, pears, and raspberries. In this study, we designed to understand how E. amylovora affected other bacterial communities on apple rhizosphere; twig and fruit endosphere; and leaf, and fruit episphere. Limited studies on the understanding of the microbial community of apples and changes the community structure by occurrence of the fire blight disease were conducted. As result of these experiments, the infected trees had low species richness and operational taxonomic unit diversity when compared to healthy trees. Rhizospheric bacterial communities were stable regardless of infection. But the communities in endosphere and episphere were significanlty affected by E. amylovora infection. We also found that several metabolic pathways differ significantly between infected and healthy trees. In particular, we observed differences in sugar metabolites. The finding provides that sucrose metabolites are important for colonization of E. amylovora in host tissue. Our results provide fundamental information on the microbial community structures between E. amylovora infected and uninfected trees, which will contribute to developing novel control strategies for the fire blight disease.

• The Plant Pathology Journal
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• 제24권2호
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• pp.152-158
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• 2008

A peculiar virus-like disease of tomato showing yellow mosaic and necrotic spots on leaves and necrosis on veins, petioles and stems was observed at the Tomato Experimental Station (TES), Buyeo, Chungcheongnamdo, Korea. The disease incidence at TES fields ranged from 21 to 35% infecting different tomato cultivars. For this reason, to identify the virus infecting tomato and to characterize the virus based on biology, serology, cytology and at molecular level. Here, leaf samples were randomly collected from different infected tomato cultivars at TES fields and greenhouses and tested by ELISA using Pepper mottle virus (PePMoV) and Tomato mosaic virus (ToMV) antisera. Infected saps were mechanically inoculated in different host plants to test for pathogenicity, symptomatology and host ranges. Infected tissues and ultrathin sections were examined by electron microscopy. Finally, putative coat protein and 3'-untranslated region (CP/3'-UTR) fragment was amplified and cloned for sequence determination and analyzed its genetic relationship to existing PepMoV and PVY sequences at the Genbank. Results showed 69% of the samples were positive with PepMoV, 13% with ToMV and 19 % were doubly infected with PepMoV and ToMV. Symptoms greatly varied from different host plants inoculated with tomato leaf sap infected with PepMoV alone and discussed in detailed in this paper. Electron microscopy from infected tissues showed filamentous particles of 720-750nm in length, a typical morphology and size of PepMoV. In addition, cylindrical inclusion bodies, pinwheels, scrolls and laminates with masses of fibrillar inclusions were also found in ultrathin sections. Alignment of the sequences of the CP/3'-UTR revealed >96% sequence identity with PepMoV and only <61% with PVY. Taken together, all these evidences presented clearly indicated that the causal agent infecting tomato at TES was PepMoV and we designated this PepMoV infecting tomato as Tom-sd2 strain in this study.

• 식물병연구
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• 제10권1호
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• pp.34-38
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• 2004

보리호위축병(BaYMV)에 의한 보리의 생육 피해 및 세포학적 변화를 조사하였다. 보리호위축병에 이병된 포장의 보리는 생육 및 수량 구성요소가 피해를 받은 것으로 조사되었다. 보리호위축병에 의해 간장은 건전주에 비해 25cm 작아져 36%의 간장 단축율을 보였으며, 이 줄기신장의 억제는 $m^2$당 수수와 수당립수 등을 감소시켰다. 이들 생육의 피해로 인해 이병포장에서의 수량은 건전포장에 비해 70%이상 감소된 것으로 조사되었다. BaYMV에 감염된 보리 잎에는 전형적인 Bymovirus의 pinwheel형의 세포내 봉입체의 형성이 확인되었다. 또한 BaYMV는 줄기 신장과 관계가 있는 줄기와 추수도, 그리고 마디조직의 세포 신장에 영향을 미치는 것으로 조사되었다. 특히, 줄기의 세포는 표피세포의 길이나 유관속 조직 크기와 같은 세포 생장에 큰 피해를 받은 것으로 조사되었다. 추수도 조직에서는 섬유조직과 cortex 세포의 크기에서 뚜렷한 차이를 보였으며, 마디 조직에서는 건전주의 조직 전체 크기가 이병주에 비해 1.5배 정도 큰 결과를 보였다. 이들 결과는 BaYMV의 감염은 세포의 신장이 억제에 영향을 미치고, 이는 보리의 줄기 신장과 생육을 억제하게 되어 결국 수량 감소를 일으키는 것으로 나타났다.

• The Plant Pathology Journal
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• 제25권2호
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• pp.128-135
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• 2009

The survival of Colletotrichum acutatum was investigated in soil, infected fruits, and infected fruit debris incorporated into soil at several temperatures with different soil moisture levels. Samples were examined at 2-week intervals for 18 weeks to determine the survival of the pathogen based on the number of colony forming unit (CFU) of C. acutatum recovered on a semi-selective medium. C. acutatum conidia survived in both sterile and non-sterile soil at 4 and $10^{\circ}C$ for 18 weeks. If infected pepper fruits were completely dried, C. acutatum survived for 18 weeks at temperature from 4 to $20^{\circ}C$. Soil temperature and moisture affected the survival of C. acutatum in infected fruit debris incorporated into soil after air-drying. The effect of soil moisture on survival was weaker at low temperatures than at high temperatures. For up to 16 weeks, conidia were recovered from fruit debris in soil that had been kept at 4 to $20^{\circ}C$ and below 6% soil moisture. Conidia were recovered from fields until approximately 6 months after pepper fruits were harvested. Using PCR with species-specific primers and a pathogenicity test, we identified conidia recovered from soil and infected fruit from both the laboratory and field as C. acutatum and as the primary inoculum causing pepper anthracnose.

• The Plant Pathology Journal
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• 제19권4호
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• pp.217-220
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• 2003

Zucchini squash (Cucurbita pepo cv. Black Beauty) plants infected with A strain of Zucchini yellow mosaic virus (ZYMV-A) isolated from a hollyhock plant showed systemically severe mosaic symptom, similar to previously established Cu strain of ZYMV. However, initial symptom of squash infected by ZYMV-A strain was generally more severe than those infected by ZYMV-Cu. Using leaf-detachment assay, examination of kinetics of accumulation of the coat protein (CP) in systemic loaves of squash plants showed that CPs of ZYMV-A appeared earlier than those of ZYMV-Cu. However, both ZYMV-A and ZYMV-Cu showed similar kinetics of CP accumulation 7 days post-inoculation. These results indicate that different rates and initial severity of systemic symptom development were due to differences in the rate of movement rather than vims replication.