• Journal of Plant Biology
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• 제3권1호
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• pp.32-38
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• 1960

Since the peculiar virus disease of chinese date tree (Zizyphus jujuba Mill. var. inermis Rehd.) has been noted in South Korea around 1950, 70% to 80% of the economically important trees have been either completely destroyed or infected with the virus, severe damage has been noted, particularly, across the area ranged from middle east to the middle part of Korea, including Seoul area. Yoon-Koock-Byung in 1958 first reported the disease and descirbed it might be caused by a kinds of yellows. But he did not conform in his paper that the disease is pecisely caused by yellows virus. The authors, hereby intend to identify the true cause of the desease of the chinese data tree by studying the external symptoms of the disease and the internal morphological characteristics of the diseaset plant which shows various abnormalities in contrast to the healthy checks. In view of fact that leaves of the infected plants become yellowish in color similar to the peach yellows, aster yellows, it is likely to be identifiable as the common yellows. Furthermore, the abnormal characteristics observed by the authors are as follow: The floral organs such as petals, sepals, stamens, and pistil turn into vegetative leaves, the leaves on heavily infected plant appear as small sized one and also showing as a common witch's broom like symptom. There are also an occuring of numerous advantitious shoots developed from both of stems and roots. The amount of photosynthetic starch grains increases in parenchymatous cells, necrosis takes place in mesophyll, Particularly, Palisade Parenchyma in the leaves of infected plants are distinguished in contrast to the healthy checks. From the symptoms and the present experimetns described above, the authors are believed that the disease of chinese data tree is not caused by the yellows. It appears the disease is rather similar to the symptoms of sandal spike virus which was noted in India early in this centry. But the host plant of standal disease, Santalum albun L. and the insect vector, Jassus indicus Wal., have never been reported in Korean flora and the founa. The termperature and the otehr environmental factors is quite different Korea and India. Thus the authors believe that the peculiar disease must be an endemic new virus origin in Korea and must be called as "shoot cluster disease of chinese date tree."

• The Plant Pathology Journal
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• 제18권3호
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• pp.109-114
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• 2002

To evaluate the phylogenetic and taxonomic status of the phytoplasmas associated with water dropwort (Oenanthe javanica DC) disease in Korea and Japan, their 16S rDNA was analyzed. DNAs extracted from water dropworts collected in Korea (Kyongnam province) and Japan (Chiba prefecture) affected by witches' broom and yellows were subjected to PCR using phytoplasma-specific primers, which amplified a 1.4-kbp fragment that included the 16S rDNA. Phytoplasmas were characterized by RFLP analysis using AluI, HaeIII, HhaI, KpnI, MseI, and RsaI restriction enzymes and by sequence analysis of the PCR products. The mater dropwort witches'broom (WDWB) and water dropwort yellows (WDY) 16S rDNA sequences were identical and closely related to onion yellows (OY, 99.9% identity), which belong to the aster yellows (AY) 16S-subgroup. However, the KpnI RFLP analyses clearly distinguished the WDY and WDWB phytoplasmas from the OY phytoplasma. The phylogenetic analysis based on 16S rDNA showed that WDWE and WDY phytoplasmas are members of a relatively homogeneous group that evolved from a common ancestor.

• The Plant Pathology Journal
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• 제31권4호
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• pp.371-378
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• 2015

Surveys of yellowing viruses in plastic tunnels and in open field crops of melon (Cucumis melo cultivar catalupo), oriental melon (C. melo cultivar oriental melon), and cucumber (C. sativus) were carried out in two melon-growing areas in 2014, Korea. Severe yellowing symptoms on older leaves of melon and chlorotic spots on younger leaves of melon were observed in the plastic tunnels. The symptoms were widespread and included initial chlorotic lesions followed by yellowing of whole leaves and thickening of older leaves. RT-PCR analysis using total RNA extracted from diseased leaves did not show any synthesized products for four cucurbit-infecting viruses; Beet pseudo-yellows virus, Cucumber mosaic virus, Cucurbit yellows stunting disorder virus, and Melon necrotic spot virus. Virus identification using RT-PCR showed Cucurbit aphid-borne yellows Virus (CABYV) was largely distributed in melon, oriental melon and cucumber. This result was verified by aphid (Aphis gossypii) transmission of CABYV. The complete coat protein (CP) gene amplified from melon was cloned and sequenced. The CP gene nucleotide and the deduced amino acid sequence comparisons as well as phylogenetic tree analysis of CABYV CPs showed that the CABYV isolates were undivided into subgroups. Although the low incidence of CABYV in infections to cucurbit crops in this survey, CABYV may become an important treat for cucurbit crops in many different regions in Korea, suggesting that CABYV should be taken into account in disease control of cucurbit crops in Korea.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.73.2-73
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• 2003

Typical whiches broom symptoms caused by phytoplasma were observed in Ash (Fraxinus rhynchophylla Hence) in Korea. The symptoms were showing abnormally small leaves, short internodes, and proliferation of shoots. Fluorescence and electron microscopy of leaf midribs revealed phytoplasma positive DAPI fluorescence and numerous phytoplasma bodies localized in the phloem sieve tubes. Phytoplasma DNA of 1.8 Kb was detected consistently from all symptomatic samples by the amplification of phytoplasma DNA with the phytoplasma specific primer pair Pl/P7. But no phytoplasma DNA was detected in healthy ash seedlings. Based on sequence analyses of an amplified region, this phytoplasma is closely related to Eqilodium phyllody, Mulberry dwarf, and Aster yellows phytoplasmas with the homology of 99.95 ％, 99.79 ％ and 99.78 ％, respectively, This phylogenetic analyses indicate that ash witches broom phytoplasma but is evidently distinct from the ash yellows group 16SrⅦ and should be classified into the Aster yellows group 16SrⅥ.

• 식물병연구
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• 제29권1호
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• pp.52-59
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• 2023

Cucurbit chlorotic virus (박과퇴록황화바이러스, CCYV)는 수박, 오이 등의 박과작물에 영향을 미치는 식물바이러스로 담배가루이에 의해 전반된다. 2018년 충북 오이에서 처음 진단된 이후 경상도 등 다른 지역에서도 보고되고 있다. 2020년 충북 진천, 음성지역의 박과작물 온실의 황화 바이러스병 조사에서 멜론, 수박, 잡초 등 채집시료 총 79시료에 대한 CCYV 특이 프라이머를 이용한 reverse transcription-polymerase chain reaction 결과 멜론 4개의 시료에서 CCYV가 확인되었다. 3점은 CCYV 단독감염, 1점는 Cucurbit aphid borne yellows virus와 Watermelon mosaic virus 복합감염으로 나타났다. 4개의 CCYV ES 분리주로부터 RNA 1, 2의 전체게놈을 얻었고, 이전에 GenBank에 보고된 CCYV 분리주들과 염기서열을 분석하였다. MEGA를 이용하여 계통분석결과 ES 분리주들은 하나의 그룹으로 나타났고, 중국 분리주들과 밀접한 관련이 있었다. ES 분리주들 유전적 다양성이 낮은 것으로 나타났고, 일반적으로 CCYV은 기주 및 지리적 기원에 따라 유전적 다양성이 거의 없었다. CCYV는 박과작물 생산에 심각한 위협이 될 가능성이 있다. 수박, 잡초 등을 포함한 다양한 CCYV 분리주에 대한 병원성, 가루이 전염 등의 특성에 대한 추가적인 연구가 필요하다.

• The Plant Pathology Journal
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• 제21권2호
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• pp.132-136
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• 2005

Two groups of phytoplasma were identified in chrysanthemum(Dendranthema grandiflorum) cv. Chunkwang showing distinct symptoms. Isolate Ph-ch1 showed symptoms of dwarf, witches'-broom, rosette and root death. The other isolate, Ph-ch2, revealed symptoms of dwarf, yellowing, leaf cupping, vein clearing and root death. The presence of phytoplasma structures in chrysanthemum leaf tissue was confirmed by transmission electron microscopy. The 16S rRNA gene was amplified from isolates Ph-ch1 and Ph-ch2 by PCR and cloned, and the nucleotide sequences were determined. In RFLP analysis, isolate Ph-ch2 showed profiles identical to Ph-ch1, except with restriction enzymes HhaI and MseI. The sequence data showed that isolate Ph-ch1 was most closely related to the aster yellows (AY) phytoplasma, and isolate Ph-ch2 was more closely related to stolbur phytoplasma than to AY phytoplasma. This is the first reported observation of stolbur phytoplasma in chrysanthemum species.

• Journal of Forest and Environmental Science
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• 제39권1호
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• pp.49-54
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• 2023

For unknown reasons, a few trees in a private chestnut orchard in Icheon si, Gyunggi-do suffered leaf chlorosis and growth decline. Based on symptoms, phytoplasma was a probable cause. Leaf samples were collected from two symptomatic and non-symptomatic trees in the orchard for phytoplasma detection. An amplicon of about 1.2 bp size was obtained from both symptomatic trees by PCR with the universal 16S rDNA primers. Sequences of these amplicons were found to have 99% nucleotide sequence identity to the corresponding genomic region of 16SrIII (X-disease group). More than 100 phytoplasma isolates, such as Candidatus phytoplasma pruni, Milkweed yellows phytoplasma, Goldenrod yellows phytoplasma, Tsuwabuki witches'-broom phytoplasma, Candidatus Phytoplasma trifolii, etc. were involved in the list. Phylogenetic analysis revealed that the sequence obtained in this study closely clustered with Candidatus phytoplasma groups. While one of the amplicons shared 91% identity with the Candidatus phytoplasma castaneae, the other shared only 47%. It needs further analysis and investigation to determine the exact taxonomy. Meanwhile, based on the analysis of the sequences, chlorosis, and small leaves were associated with phytoplasma.

• The Plant Pathology Journal
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• 제36권1호
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• pp.76-86
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• 2020

Cucumber mosaic virus (CMV) is damaging to the growth and quality of lettuce crops in Lanzhou, China. Recently, however, for the first time an isolate of lettuce necrotic yellows virus (LNYV) has been detected in lettuce crops in China, and there is concern that this virus may also pose a threat to lettuce production in China. Consequently, there is a need to develop a rapid and efficient detection method to accurately identify LNYV and CMV infections and help limit their spread. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) assays were developed to detect the nucleoprotein (N) and coat protein (CP) genes of LNYV and CMV, respectively. RT-LAMP amplification products were visually assessed in reaction tubes separately using green fluorescence and gel electrophoresis. The assays successfully detected both viruses in infected plants without cross reactivity recorded from either CMV or LNYV or four other related plant viruses. Optimum LAMP reactions were conducted in betaine-free media with 6 mM Mg²⁺ at 65℃ for LNYV and 60℃ for 60 min for CMV, respectively. The detection limit was 3.5 pg/ml and 20 fg/ml using RT-LAMP for LNYV and CMV plasmids, respectively. Detection sensitivity for both RT-LAMP assays was greater by a factor of 100 compared to the conventional reverse transcription polymerase chain reaction assays. This rapid, specific, and sensitive technique should be more widely applied due to its low cost and minimal equipment requirements.

• 식물병연구
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• 제24권4호
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• pp.276-284
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• 2018

In 2010, foliar symptoms were observed in the paprika leaves in Jinju city, Korea. Beet western yellows virus (BWYV) was identified in paprika by using the large-scale oligonucleotide chip assay. To investigate the occurrence of BWYV, a survey was performed on various crops, including paprika, from 2011 to 2014. Further, the presence of BWYV was consistently verified through literature survey from 2015 to 2017. BWYV infection has been identified in Solanaceae crops (bell pepper, hot pepper, and paprika), various weeds, and green peach aphids and it occurs on a nationwide scale. Cultivation using organic methods involved natural enemies and showed a high BWYV infection rate, which was more than that for conventional cultivation methods in greenhouse. The complete genome sequence of BWYV isolated from paprika was determined for the first time. The genome of the BWYV-Korea isolate consists of 5750 nucleotides and has six open reading frames. Sequence identity results showed maximum similarity between the BWYV-Korea isolate and the BWYV LS isolate (identity > 90%). This study is the first report of BWYV infecting paprika in Korea. The survey revealed that BWYV is naturalized in the domestic ecology of Korea.

• 식물병연구
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• 제29권1호
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• pp.88-93
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• 2023

충북지역 수박과 멜론재배지에서 2020년부터 2021년까지 시료를 채집하여 reverse transcription polymerase chain reaction으로 유전자 진단을 실시해 바이러스 발생현황을 조사하였다. 2020년 수박에서는 정식 전 접목묘에 대해 바이러스를 검정했을 때 음성군과 진천군 두 곳에서 cucumber green mottle mosaic virus (CGMMV)만이 각각 8%의 감염률을 보였다. 6월에는 진천군과 음성군 모두에서 watermelon mosaic virus (WMV), CGMMV, cucurbit aphid-borne yellows virus (CABYV)가 공통적으로 검출되었으며, 감염률은 진천군이 WMV 3.7%, CGMMV 11.1%, CABYV 3.7%이었고 음성군은 WMV 15.8%, CGMMV 33.3%, CABYV 3.5%로 음성군이 진천군에 비해 WMV와 CGMMV 감염률이 높았다. 2021년 3월부터 5월까지 월별로 수박재배지에서 바이러스를 검정했을 때 3월에는 음성군과 진천군 모두에서 바이러스가 검출되지 않았으며, 4월에는 진천군에서 CGMMV 1.6%, 음성군에서는 WMV 0.4%, CGMMV 38.5% 발생하였다. 5월에는 진천군에서 cucumber mosaic virus (CMV) 35%, CGMMV 10%, 음성군에서는 CMV 20.9%, CGMMV 29% 발생하였다. 충북지역에서 수박 바이러스 조사기간 동안 zucchini yellow mosaic virus (ZYMV)와 cucurbit chlorotic yellows virus (CCYV)는 검출되지 않았으며, 2020년에는 발생되지 않았던 CMV가 2021년도에 발생하였다. 2020년부터 2021년까지 멜론재배지에서 최근 문제가 되고 있는 CABYV와 CCYV 발생을 조사했을 때 CABYV는 조사기간 동안 음성군과 진천군 모두에서 발생되었고 감염률은 53.9-92.2%였다. CCYV는 2020년에 음성군에서만 20.8% 2021년에는 진천군에서만 2.7% 발생하였다.