• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.223-235
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• 1987

Samples showing yellow mosaic symptom of Lilium spp. with necrotic fleck, stunting, malformation, and colour breaking were collected from lily-growing areas in the southern part of Korea. Two viruses were distinguished under a electron microscope and their host range, serological reaction, stability in sap, type of aphid transmission, and relations with cells and tissues were examined. Broad bean wilt virus (BBWV) was transmitted by sap-inoculation to 23 plant species in 8 families and by the aphid, Myzus persicae. This virus was inactivated after 10 min at 70C, at dilution of $10^{-3}$, and after 6 days at about 20C. Electron microscopic examination of purified preparation showed that the virus is spherical particle of 28nm in diameter. The virus reacted positively with BBWV-antiserum in agar gel diffusion test. In ultrathin sections of BBWV infected tissues, large aggregates or crystalline array of virus particles and vesicular body were found in the cytoplasm, vacuole, and nucleus of mesophyll cells. Cucumber mosaic virus (CMV) was transmitted by sap-inoculation. Electron microscopic examination of its purified preparation showed spherical particles of 30nm in diameter. The virus reacted positively with CMV-Y strain-antiserum in agar gel diffusion test. In ultrathin sections of CMV infected tissues, crystalline array of virus particles were found in the vacuole and a large number 0f virus particles were found in the cytoplasm and the plasmodesmata of mesophyll cells. When each of these viruses was retransmitted to Lilium tigrinum. L. concolor, and L. auratum, BBWV induced slight symtoms and colour breaking, but CMV induced yellowing mosaic or necrotic fleck.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.189-195
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• 2020

The soybean (Glycine max L.), also known as the soya bean, is an economically important legume species. Pathogens are always major threats for soybean cultivation. Several pathogens negatively affect soybean production. The soybean is also known as a susceptible host to many viruses. Recently, we carried out systematic analyses to identify viruses infecting soybeans using soybean transcriptome data. Our screening results showed that only few soybean transcriptomes contained virus-associated sequences. In this study, we further carried out bioinformatics analyses using a soybean flower bud transcriptome for virus identification, genome assembly, and single nucleotide variations (SNVs). We assembled the genome of Soybean yellow common mosaic virus (SYCMV) isolate China and revealed two SNVs. Phylogenetic analyses using three viral proteins suggested that SYCMV isolate China is closely related to SYCMV isolates from South Korea. Furthermore, we found that replication and mutation of SYCMV is relatively low, which might be associated with flower bud tissue. The most interesting finding was that SYCMV was not detected in the cytoplasmic male sterility (CMS) line derived from the non-CMS line that was severely infected by SYCMV. In summary, in silico analyses identified SYCMV from the soybean flower bud transcriptome, and a nearly complete genome of SYCMV was successfully assembled. Our results suggest that the low level of virus replication and mutation for SYCMV might be associated with plant tissues. Moreover, we provide the first evidence that male sterility might be used to eliminate viruses in crop plants.

• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.291-298
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• 1987

Samples showing mosaic symptom of cowpea (Vigna sesquipedalis) with vein banding, chlorotic spot, vein yellow were collected from Chinju areas in Korea, Two viruses were distinguishable by stability in sap, host range, and relations with cells and tissues were examined under an electron microscope, Blackeye cowpea mosaic(BICMV) was sap-transmissible to 7 plant species in 2 families, Of the plants, only leguminous species were systemically infected. This virus was inactivated by heating at $50-65^{\circ}C$ for 10 min, by diluting at $10^{-4}-10^{-5}$, and aging at room temperature for 1-6 days. Preparations examined under the electron microscope by direct negative staining method(DN -method) always showed particles of flexuous filament bout 750nm in length and cytopasmic inclusions. Cytoplasmic inclusions and virus particles were also confirmed to present in the cytoplasm of a mesophyll cell by ultrathin sections of BICMV infected cowpea leaves. Cucumber mosaic virus (CMV) was transmitted by sap- inoculation on inoculated leaves of Chenopodium amaranticolor, C. quinoa producing local lesions, but non-inoculated upper leaves of Nicotiana glutinosa, Cucurbita pepo and Vigna sesquipedalis producting systemic mosaic symptoms. Electron microscopic examination of virus preparation by direct negative staining showed spherical particles of about 30nm in diameter. In ultrathin sections of CMV infected tissues, virus particles of crystalline array were found in the vacuole and a large number of virus particles were found in the cytoplasm and the plasmodesmata of mesophyll cells.

• The Plant Pathology Journal
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• v.16 no.5
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• pp.269-279
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• 2000

Alfalfa mosaic alfamoviruses(AIMV) were isolated from infected potato (Solanum tuberosum) and azuki bean (Paseolus angularis) in Korea. Two AIMV isolated from potatoes were named as strain KR (AIMV-KR1 and KR2) and AIMV isolated from azuki bean was named as strain Az (AIMV-Az). Each isolated AIMV strain was characterized by using their host ranges, symptom developments, serological relations and nucleotide sequence analysis of coat protein (CP) gene. Strains KR1, KR2, and Az were readily transmitted to 20 of 22 inoculated plant species including bean, cowpea, tomato, tobacco, and potato. AIMV-KR1 and KR2 produced the typical symptoms like chlorotic or necrotic spots in Chenopodium quinoa and Solanum tuberosum cv. Superior. AIMV-Az caused bright yellow mosaic symptom and leaf malformation in Nicotiana glauca, which were different from the common mosaic symptom caused by AIMV-KR1 and KR2. Electron microscope observation of purified virus showed bacilliform virions containing a single-stranded plus-strand RNAs of 3.6, 2.6, 2.0 and 0.9 kbp in length, respectively, similar in size and appearance to those of Alfamovirus. In SDS-PAGE, the coat protein of the two viruses formed a consistent band that estimated to be about 24kDa. The CP genes of the AIMV strains, KR1, KR2, and Az have been amplified by RT-PCR using the specific primers designed to amplify CP gene from viral RNA-3, cloned and sequenced. Computer aided analysis of the amplified cDNA fragment sequence revealed the presence of a single open reading frame capable of encoding 221 amino acids. The nucleotide and peptide sequence of viral CP gene showed that strain KR1, KR2, and Az shared highest nucleotide sequence identities with AIMV strain 425-M at 97.7%, 98.2%, and 97.2%, respectively. CP gene sequences of two strains were almost identical compared with each other. Altogether, physical, serological, biological and molecular properties of the purified virus.

• Korean journal of applied entomology
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• v.19 no.4 s.45
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• pp.193-198
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• 1980

This paper deals with the studies on the occurence of a new virus disease of sesame and the identification of the causal virus. The virus disease of sesame has been regarded as a widespread disease in the sesame-growing areas in the southern part of Korea. The disease was found to be caused by watermelon mosaic virus (WMV). During the years since 1978, stunting of sesame plants, with yellow mosaic, necrotic spot, and malformation, were collected from 17 different places. Virus isolates from 27 out of 32 samples were identified as WMV. Natural infection of squash, pumpkin, cucumber, and watermelon by WMV as well as sesame was proved. The virus is inactivated at temperatures of 55 to $60^{\circ}C$, at dilution of $10^{-3}\;to\;10^{-4}$, and in the aging of 10 to 14 days at about $20^{\circ}C$. Sesame, Chenopodium amaranticelor, pea, bean, as well as many plants of the Cucurbitaceae, are susceptible to the sesame-isolates of WMV. In negatively stained preparations, particles of the virus appear under the electron microscope as flexible filaments of about $750\~800nm$ in length. Cylindrical inclusions and virus particles were found in the cytoplasm of mesophyll cells by ultra-thin sections of WMV infected tissues.

• Research in Plant Disease
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• v.18 no.4
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• pp.277-289
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• 2012

The total number of requests and associated specimens for the diagnosis of virus infection were 573 and 2,992, respectively, on crops from agricultural places of farmers, Agricultural extension services and so forth for 5 years from 2007. The total number of virus tests was 13,325. The number of species of viruses infected on the submitted crops was 21 in 2007, 15 in 2008, 23 in 2009, 21 in 2010 and 17 in 2011. The newly recorded viruses were Tobacco leaf curl virus (TbLCV) in 2007, Tomato yellow leaf curl virus (TYLCV) in 2008, Impatience necrotic spot virus (INSV) and Radish mosaic virus (RaMV) in 2009, and Beet western yellows virus (BWYV) in 2010. Forty virus species including Alfalfa mosaic virus were detected over 5 years. The ten most frequently detected virus species were Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), Tomato leaf curl virus (TYLCV), Cucumber green mottle mosaic virus (CGMMV), Broad bean wilt virus 2 (BBWV2), Zucchini yellow mosaic virus (ZYMV), Melon necrotic spot virus (MNSV), Pepper mild mottle virus (PMMoV), Watermelon mosaic virus (WMV) and Pepper mottle virus (PepMoV). The types of crops submitted from agricultural places were 51 in total and the ten most frequently submitted crops were red pepper, tomato, paprika, watermelon, melon, rice, cucumber, corn, radish and gourd. The total request rate for the top 10 crops and top 20 crops was 81.6% and 94.2%, respectively. Eight pepper infecting virus species included CMV, and the average infection rate was 24.6% for CMV, 18.9% for PMMoV and 14.7% for TSWV. Seven kinds of double infection were detected in pepper including BBWV2+CMV at 14.7% on average, and four types of triple infection including BBWV2+CMV+PepMoV at 0.9% on average. Six virus species detected on tomato including TYLCV, and the average infection rate was 50.6% for TYLCV, 14.5% for TSWV and 10.9% for Tobacco leaf curl virus (TbLCV). The mixed infection of CMV+TSWV on tomato was 3.9% on average and of Tomato mosaic virus (ToMV)+TYLCV was 0.4% on average. Five viruses detected on watermelon included MNSV and the average infection rate was 37.0% for MNSV, 20.4% for CGMMV, 18.1% for ZYMV and 17.8% for WMV. The mixed infection rate on watermelon was CMV+MNSV and WMV+ZYMV having an average infection rate of 0.7% and 5.0%, respectively. The average infection rates on melon were 77.6% for MNSV, 5.6% for CMV and 3.3% for WMV. Mixed infections of CMV+MNSV occurred on melon with an average infection rate of 13.5%.

• Research in Plant Disease
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• v.15 no.1
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• pp.1-7
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• 2009

Viruses diagnosed on crops including rice plants from farmers or agricultural extension agencies cover the country were 11 species including Broad bean wilt virus 2 (BBWV2) in 2008. Tomato spotted wilt virus (TSWV) was the most important virus having the detection rate of 22.9%. Two viruses of Tomato yellow leaf curl virus (TYLCV) and Tobacco leaf curl virus (TLCV) inducing leaf yellow and curl diseases on tomatoes were occurred newly with the detection rate of 12.2% and 4.0%, respectively, in 2008. Rice stripe virus (RSV) was occurred on 869.5 ha mainly at Jindo and Haenam areas in Jeollanamdo province. At Jindo area, 12 plots were damaged severely with the infected hill rate of 83.8%. At the main production area of oriental melon at Seongju, almost all fruits from whole sale market at Seongju were infected with Cucumber green mottle mosaic virus (CGMMV) as the detection rate of 87%. The areas occurred TSWV in Korea were 25 totally from 2003 including 7 areas newly reported in 2008 including Naju in Jeoallanamdo. TSWV could be reduced as 0.1 % from 5.3% by covering insect proof net in vinyl house after chemical soil sterilization. Tomato yellow leaf curl disease was occurred on April in 2008 at Tongyoung area in Kyeongsangnamdo, and detected continuously at 13 areas, 7 in Kyeongsangnamdo, 4 in Jeollabukdo and 2 in Jejudo. Potato spindle tuber viroid (PSTVd) was occurred abruptly in a confined space of a civil breeding greenhouse and a cultivar evaluation field followed by disuse 17.4 M/T of potato tubers. No PSTVd was detected at 17 fields cultivated the related potatoes to the bred company by RT-PCR.

• Research in Plant Disease
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• v.17 no.3
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• pp.334-341
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• 2011

The kinds of crop requested from agricultural actual places of famers, Agricultural extension services and so forth was 8 including red pepper for vegetables, 4 including apple for fruit trees and 6 including chrysanthemum for flowers in 2010. The important vegetables in clinical diagnosis of viral diseases were tomato, watermelon and red pepper having the requested rate of 31.8%, 21.4% and 19.5%, respectively. On fruit trees, grape and apple were most common with the requested rate of 63.6% and 33.0%, orderly. On floral crops, tulip and cactus were damaged by viral diseases with the requested rate of 60.0% and 20.0%, orderly. On peppers and tomatoes, six viruses including Cucumber mosaic virus (CMV) and Broad bean wilt virus 2 (BBWV2) infected. Five viruses including Melon necrotic spot virus (MNSV) and CMV were identified from watermelons. On grapes, six viruses including Grapevine fleck virus (GFkV) infected. CMV was identified from six vegetables including pepper out of 8 kinds of vegetables and tulip plant. Total agents of virus and viroid species were 32 and 4 species, respectively, in 2010. Tomato yellow leaf curl disease by Tomato yellow leaf curl virus and Tobacco yellow leaf curl virus was occurred newly at 18 Si/Gun areas including Buan, Jeonbuk province in 2010 and the total areas were increased up to 58 Si/Gun from the first incidence in 2008. Tomato spotted wilt virus (TSWV) occurred newly at two areas of Jinan, Jeonbuk and Jeju in Jeju province in 2010, and the incidence areas were expanded to 25 Si/Gun areas from severe occurrence at Anyang area in 2004. No incidence of TSWV was recorded only in Gyeongbuk and Chungbuk province. Tomato bushy stunt virus occurred newly at Jinju, Gyeongnam, and it had the total incidence areas of 5 Si/Gun after first observation at Sacheon, Gyeongnam in 2004.