• 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.

• The Plant Pathology Journal
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• 제32권5호
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• pp.377-387
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• 2016

Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, is one of the most important viruses of cultivated tomatoes worldwide, mainly causing yellowing and curling of leaves with stunting in plants. TYLCV causes severe problems in sub-tropical and tropical countries, as well as in Korea. However, the mechanism of TYLCV infection remains unclear, although the function of each viral component has been identified. TYLCV C4 codes for a small protein involved in various cellular functions, including symptom determination, gene silencing, viral movement, and induction of the plant defense response. In this study, through yeast-two hybrid screenings, we identified TYLCV C4-interacting host proteins from both healthy and symptom-exhibiting tomato tissues, to determine the role of TYLCV C4 proteins in the infection processes. Comparative analyses of 28 proteins from healthy tissues and 36 from infected tissues showing interactions with TYLCV C4 indicated that TYLCV C4 mainly interacts with host proteins involved in translation, ubiquitination, and plant defense, and most interacting proteins differed between the two tissues but belong to similar molecular functional categories. Four proteins-two ribosomal proteins, S-adenosyl-L-homocysteine hydrolase, and 14-3-3 family protein-were detected in both tissues. Furthermore, the identified proteins in symptom-exhibiting tissues showed greater involvement in plant defenses. Some are key regulators, such as receptor-like kinases and pathogenesis-related proteins, of plant defenses. Thus, TYLCV C4 may contribute to the suppression of host defense during TYLCV infection and be involved in ubiquitination for viral infection.

• 한국환경농학회지
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• 제19권2호
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• pp.154-159
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• 2000

대기환경오염원인 오존을 벼와 콩에 처리하여 오존피해증상, 품종간 저항성 차이 및 유전양상을 밝히고자 가시피해, 피해엽율, 엽록소함량, 임실율 등을 조사한 결과를 요약하면 다음과 같다. 벼의 오존피해증상은 피해정도에 따라 잎에 작고 붉은 반점이 형성되거나 잎전체가 적갈색 또는 황백색으로 변색되며 잎끝부터 말리면서 고사하였다. 콩은 피해엽이 황백색 또는 흑갈색으로 변색되었으며 벼와 콩 모두 잎의 표면보다는 이면이, 신엽보다는 하위엽에서 뚜렷하게 나타났다. 벼의 오존저항성 정도는 밀양 23호와 농안벼가 저항성을, 추청벼가 감수성으로 조사되었다. 오존처리시간이 2시간에서 8시간으로 길어짐에 따라 벼의 피해엽율은 증가하였고 엽록소함량은 감소하는 경향이었지만 그 정도는 품종에 따라 다르게 나타났다. 콩의 품종별 오존저항성정도는 큰올콩과 단엽콩이 저항성을, 두유콩, 무한콩, 은하콩 및 푸른콩 등이 감수성으로 나타났다. 콩의 생육시기별 피해엽율은 품종에 따라 다소 다른 경향이었으나 대체로 파종후 45일 처리에서 피해엽율이 가장 높았다.

• 아시안잔디학회지
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• 제6권2호
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• pp.99-111
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• 1992

국내 골프장에 식재된 bentgrass (Agrostis palustris Huds), zoysiagrass (Zoysia japonica Steud) 및 Kentucky bluegrass (Poa pratensis L.)에 잎마름증상(yellow patch)을 나타내는 병반 부위에서 병원균을 분리ㆍ동정한 결과 2핵성인 Rhizoctonia cerealis로 동정되었다. 병원균은 잔디의 관부와 엽조직을 침해하였으며, 병징은 bentgrass의 경우 1m 내외의 둥근 고리모양의 병반을 형성하고, 병반 가장자리의 잔디잎은 초기에는 붉은색을 띠며 병이 진전됨에 따라 갈변하였다. Zoysiagrass에는 직경 30~40cm의 근사원형의 병반이 봄철 맹아시기에 발생하고, 병반 부위에서는 잔디가 맹아되지 않았다. 맹아된 잔디에는 부정형의 볏짚색 반점이 생기면서 고사되었다. Rhizoctonia cerealis의 균사직경은 2.5~6.3$mu extrm{m}$(평균 3.8$\mu\textrm{m}$)이었으며, 균사는 담황색을 띠고, 균총의 색은 밝은 갈색을 나타냈다. Monilioid cell 크기는 5.8~12.5$\times$l3.8~37.5$\mu\textrm{m}$였으며, 배지상에서 형성된 균핵의 크기는 0.2~2.0mm, 균핵의 색은 처음에는 흰색을 띠다가 성숙해가면서 갈색을 나타냈다. 온도에 따른 균사의 생장은 23$^{\circ}C$에서 가장 양호했다. 병원성 검정 결과 분리균간에 병원성에는 다소 차이가 있었다.

• Mycobiology
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• 제47권4호
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• pp.408-414
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• 2019

Crinum asiaticum and Hymenocallis littoralis, commonly known as spider lilies are bulbous perennial and herbaceous plants that widely planted in Malaysia as ornamental. During 2015-2016, symptom of leaf blight was noticed on the hosts from several locations in Penang. The symptom appeared as irregular brown to reddish lesions surrounded by yellow halos. As the disease progressed, the infected leaves became blighted, dried, and fell off with the presence of black microsclerotia and pycnidia on the lesions parts. The present study was conducted to investigate the causal pathogen of leaf blight on C. asiaticum and H. littoralis. Based on morphological characteristics and DNA sequences of internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) gene, the causal pathogen was identified as Macrophomina phaseolina. Phylogenetic analysis of combined dataset of ITS and TEF1-α grouped the isolates studied with other isolates of M. phaseolina from GenBank. The grouping of the isolates was supported by 96% bootstrap value. Pathogenicity test proved the role of the fungus in causing leaf blight on both hosts.

• 한국작물학회지
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• 제42권2호
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• pp.160-165
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• 1997

팥 바이러스병에 대한 기초자료를 얻고자 병징의 유형과 생육 단계별 감량정도 및 수량에 미치는 영향을 조사하고 병징 유형별 바이러스를 분리 동정한 결과는 다음과 같다. 1. 팥에 발생되는 바이러스병의 병징은 크게 mosaic, yellow mosaic 및 severe mosaic의 3가지 군으로 분류되었으며 병징별 분포는 mosaic＞severe mosaic＞yellow mosaic 순이었다. 2. 성숙기까지 매개충 차단 재배시의 이병률은 1.5%(방임구 20.7%)로서 생육 후기에 감량될수록 이병률이 낮았으며 10a당 수량도 171kg으로서 방임구에 비하여 45% 증수되었다. 3. 지표식물 검정 결과 mosaic 유형은 CMV, yellow mosaic 유형은 AMV, severe mosaic 유형은 AzMV의 기주범위와 유사하였다. 4. 항혈청에 의한 각 병징별 반응결과 yellow mosaic 유형의 시요는 AMV 항 혈청과 mosaic 유형의 시요는 CMV의 항혈청과 침강선이 형성되어 각각 AMV 및 CMV의 한 계통으로 판정되었다. 5. 병징 유형별 전자현미경 관찰결과 yellow mosaic유형은 18~58$\times$18nm의 타원형 입자가 다수 관찰되었고 mosaic 증상의 시요에서는 직경 30nm의 구형 입자, severe mosaic병징의 시요에서는 730$\times$12nm의 사상형 입자와 봉입자가 관찰되었다.

• The Plant Pathology Journal
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• 제40권2호
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• pp.125-138
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• 2024

Citrus yellow vein clearing virus (CYVCV) is a member of the Alphaflexiviridae family that causes yellow vein clearing symptoms on citrus leaves. A total of 118 leaf samples from nine regions of six provinces in Korea were collected from various citrus species in 2020 and 2021. Viral diagnosis using next-generation sequencing and reverse transcription polymerase chain reaction (RT-PCR) identified four viruses: citrus tristeza virus, citrus leaf blotch virus, citrus vein enation virus, and CYVCV. A CYVCV incidence of 9.3% was observed in six host plants, including calamansi, kumquat, Persian lime, and Eureka lemon. Among the citrus infected by CYVCV, only three samples showed a single infection; the other showed a mixed infection with other viruses. Eureka lemon and Persian lime exhibited yellow vein clearing, leaf distortion, and water-soak symptom underside of the leaves, while the other hosts showed only yellowing symptoms on the leaves. The complete genome sequences were obtained from five CYVCV isolates. Comparison of the isolates reported from the different geographical regions and hosts revealed the high sequence identity (95.2% to 98.8%). Phylogenetic analysis indicated that all the five isolates from Korea were clustered into same clade but were not distinctly apart from isolates from China, Pakistan, India, and Türkiye. To develop an efficient diagnosis system for the four viruses, a simultaneous detection method was constructed using multiplex RT-PCR. Sensitivity evaluation, simplex RT-PCR, and stability testing were conducted to verify the multiplex RT-PCR system developed in this study. This information will be useful for developing effective disease management strategies for citrus growers in Korea.

• 한국연초학회지
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• 제18권2호
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• pp.107-112
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• 1996

The occurrence and chemical properties of grey tobacco leaves (Type III) found in 1995 crop of flue-cured tobacco cultivated in paddy field were investigated to compare with those of normal leaves. Cured leaves of NC82 were separated by visual characters into 3 classes of slight, fair and severe symptoms of grey leaf by the percentage of grey parts to whole leaf area. Number of samples classified with discoloring portion was the order of greyish brown > reddish brown > greyish yellow, respectively. Grey leaves of this type were mostly found among the leaves harvested from upper stalk position, and it was estimated that growth rate of upper leaves also influenced on the occurrence of grey leaves. Grey leaves showed remarkably lower b* and L* values than those of normal leaves, while a* value was mostly higher in grey leaves. These tendencies in chromatic aberration showed more remarkable difference in the degree of grey symptoms. Chemical analyses of grey leaf samples indicated that they contained less total nitrogen and nicotine, and more total sugar and starch than those of normal leaves. In chemical traits, these tendencies were accordance with the degree of grey symptoms, and within the same leaf, grey parts were decreased in total nitrogen and ether extract content compared with those of normal parts, but there was no difference in nicotine and Cl contents. Key words : grey leaf tobacco (type III), grey symptom, color, chemical properties.

• Mycobiology
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• 제46권2호
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• pp.168-171
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• 2018

In 2016, a severe leaf spot disease was found on Iris ensata Thumb. in Nanjing, China. The symptom was elliptical, fusiform, or irregularly necrotic lesion surrounded by a yellow halo, from which a small-spored Alternaria species was isolated. The fungus was identified as Alternaria iridiaustralis based on morphological characteristics. The pathogenicity tests revealed that the fungus was the causal pathogen of the disease. Phylogenic analyses using sequences of ITS, gpd, endoPG, and RPB2 genes confirmed the morphological identification. This study is the first report of A. iridiaustralis causing leaf spots on I. ensata in China.

• Weed & Turfgrass Science
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• 제5권1호
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• pp.23-28
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• 2016

전국적으로 재배중인 한국잔디에서 확대되고 있는 총생잔디에서 현미경을 이용하여 피시움균의 난포자와 유사하지만 다소 큰 사이즈인 $50{\sim}80{\mu}m$의 난포자를 관찰하였다. 동일 시료들을 암상태의 저온 다습한 조건에서 24시간 증식한 후 현미경으로 관찰한 결과 $80{\sim}100{\mu}m$ 크기의 Sclerophthora macrospora 유주자낭이 확인되었다. 유전자 분석을 통한 확인을 위해 유전자 은행에 등록된 S. macrospora 염기서열 정보를 바탕으로 제작된 프라이머와 감염된 조직에서 추출한 DNA로 PCR 후, S. macrospora 특이적인 밴드가 증폭되는 것을 알 수 있었다. 이러한 결과로 S. macrospora가 한국잔디 총생 증상에 관여하는 가능성이 있을 것으로 사료된다.