• Korean journal of applied entomology
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• v.17 no.1 s.34
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• pp.33-35
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• 1978

The infected spin aches showing yellow mosaic symptom were collected and confirmed that the causal agent was turnip mosaic virus. The results of host reaction indicated that this virus induced local lesion on the inoculated leaves of Nicotiana tabacum (B.Y) and Chenopodium amaranticolor, mosaic symptoms on chrysanthemum coronarum, spinacea oleracea and Rephanus acanthiormis. The infected leaves extracts with this virus showed positive reaction with authentic turnip mosaic virus-antiserum. The virus particles were filaments type with size of 750nm by means of dipping method in electron microscope.

• The Plant Pathology Journal
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• v.16 no.6
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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.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.363-370
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• 2015

Using the Chinese cabbage (Brassica campestris) cultivar 'Chun-goang' as a host and turnip mosaic virus (TuMV) as a pathogen, we studied the effects of ambient temperature ($13^{\circ}C$, $18^{\circ}C$, $23^{\circ}C$, $28^{\circ}C$ and $33^{\circ}C$) on disease intensity and the speed of systemic infection. The optimal temperature for symptom expression of TuMV was $18-28^{\circ}C$. However, symptoms of viral infection were initiated at $23-28^{\circ}C$ and 6 days post infection (dpi). Plants maintained at $33^{\circ}C$ were systemically infected as early as 6 dpi and remained symptomless until 12 or 22 dpi, depending on growth stage at the time of inoculation. It took 45 days for infection of plants grown at $13^{\circ}C$. Quantitative realtime polymerase chain reaction (q-PCR) results showed that the accumulation of virus coat protein was greater in plants grown at $23-28^{\circ}C$. The speed of systemic infection increased linearly with rising ambient temperature, up to $23^{\circ}C$. The zero-infection temperature was $10.1^{\circ}C$. To study the effects of abruptly elevated temperatures on systemic infection, plants inoculated with TuMV were maintained at $10^{\circ}C$ for 20 d; transferred to a growth chamber at temperatures of $13^{\circ}C$, $18^{\circ}C$, $23^{\circ}C$, $28^{\circ}C$, or $33^{\circ}C$ for 1, 2, or 3 d; and then moved back to $10^{\circ}C$. The numbers of plants infected increased as duration of exposure to higher temperatures and dpi increased.

• The Plant Pathology Journal
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• v.37 no.1
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• pp.47-56
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• 2021

Plants protect against viruses through passive and active resistance mechanisms, and in most cases characterized thus far, natural recessive resistance to potyviruses has been mapped to mutations in the eukaryotic initiation factor eIF4E or eIF(iso)4E genes. Five eIF4E copies and three eIF(iso)4E copies were detected in Brassica rapa. The eIF4E and eIF(iso)4E genes could interact with turnip mosaic virus (TuMV) viral protein linked to the genome (VPg) to initiate virus translation. From the yeast two-hybrid system (Y2H) and bimolecular fluorescence complementation (BiFC) assays, the TuMV-CHN2/CHN3 VPgs could not interact with BraA.eIF4E.a/c or BraA.eIF(iso)4E.c, but they could interact with BraA.eIF(iso)4E.a in B. rapa. Further analysis indicated that the amino acid substitution L186F (nt T556C) in TuMV-UK1 VPg was important for the interaction networks between the TuMV VPg and eIF(iso)4E proteins. An interaction model of the BraA. eIF(iso)4E protein with TuMV VPg was constructed to infer the effect of the significant amino acids on the interaction of TuMV VPgs-eIF(iso)4Es, particularly whether the L186F in TuMV-UK1 VPg could change the structure of the TuMV-UK1 VPg protein, which may terminate the interaction of the BraA.eIF(iso)4E and TuMV VPg protein. This study provides new insights into the interactions between plant viruses and translation initiation factors to reveal the working of key amino acids.

• The Plant Pathology Journal
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• v.35 no.4
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• pp.381-388
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• 2019

For several years, temperatures in the Korean peninsula have gradually increased due to climate change, resulting in a changing environment for growth of crops and vegetables. An associated consequence is that emerging species of insect vector have caused increased viral transmission. In Jeju Island, Korea, occurrences of viral disease have increased. Here, we report characterization of five newly collected turnip mosaic virus (TuMV) isolates named KBJ1, KBJ2, KBJ3, KBJ4 and KBJ5 from a survey on Jeju Island in 2017. Full-length cDNAs of each isolate were cloned into the pJY vector downstream of cauliflower mosaic virus 35S and bacteriophage T7 RNA polymerase promoters. Their fulllength sequences share 98.9-99.9% nucleotide sequence identity and were most closely related to previously reported Korean TuMV isolates. All isolates belonged to the BR group and infected both Chinese cabbage and radish. Four isolates induced very mild symptoms in Nicotiana benthamiana but KBJ5 induced a hypersensitive response. Symptom differences may result from three amino acid differences uniquely present in KBJ5; Gly(382)Asp, Ile(891)Val, and Lys(2522)Glu in P1, P3, and NIb, respectively.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.643-650
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• 2020

Korean ginseng (Panax ginseng) is a dicotyledonous, medicinal, perennial plant belonging to the genus Panax of the family Araliaceae. We investigated the occurrence and incidence of plant viruses in Panax ginseng in Korea. A total of 656 leaf samples were combined into one and total RNA was extracted from the polled sample, using RNA sequencing (RNA-Seq), a metatranscriptome analysis of the plant virome was conducted. The virus present in Panax ginseng was confirmed by reverse transcription polymerase chain reaction (RT-PCR) assay using virus-specific primers. In RNA-Seq data analysis, the multiplication protein of four viral contigs including Aristotelia chilensis virus 1 (AcV1), Turnip mosaic virus (TuMV), Watermelon mosaic virus (WMV), and Tobamovirus multiplication protein were discovered. From our metatranscriptome analysis and RT-PCR assay, TuMV and WMV were detected, whereas the three viruses reported in China such as tomato yellow leaf curl China virus; panax notoginseng virus A; and panax virus Y were not found in this study. The distribution of domestic ginseng viruses seems different from that recorded in China. Overall, this is the first plant virome analysis of Panax ginseng in Korea.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.433-439
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• 1998

The studies on the ecology of virus disease on Chinese cabbage (Brassica campestris subsp. pekinensis) cultivated in alpine area of Kangwon province during summer season to analyse its influence on damage and develope a prediction model were performed from 1993 to 1997. Virus disease on Chinese cabbage occurring in the alpine area showed various symptom types and among there, necrotic spots and dwarf were mainly detected. The disease was increased from early August and continued mid September in every year. The occurrence of virus disease was the highest in 1994 with 20.5%, and the number of aphid vectors were also the highest during the same period. The number of aphids in the alpine areas showed twice peaks every year. For the analysis of damage by virus infection, the infection and injured ratio of all treatments were more than 90% and 80%, respectively. The most important factor for the occurrence of virus disease on Chinese cabbage was temperature. Factors influencing the development of the viral disease in the alpine area were maximum temperature and number of aphid vectors.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.668-675
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• 1998

These surveys were conducted to check the occurrence of disease in various horticultural crops in alpine areas, especially Daekwallyong areas, Pyongchang-Gun, and Hyeongseong-Gun in Kangwon province. TuMV on Chinese cabbage was one of the most serious diseases, especially in 1994 and 1997. The incidence of soft rot and clubroot has been increased gradually. Brittle root rot on Chinese cabbage was significantly decreased. Soft rot, gray mold, downy mildew, powdery mildew, bottom rot and Alternaria leaf spot were the common diseases on most vegetable crops. Gray mold (Botrytis cinerea) on celery, cercospora leaf spot (Cercospora sp.) on melon, powdery mildew (Erysiphe cichoracearum) on lettuce, and clubroot (Plasmodiophora brassicae) on parsley are newly found in Korea. The most common and predominant diseases were viruses, especially CMV, TMV, TuMV, BBMV, and gray mold, wilts, and cercospora leaf spot on many flowers in alpine areas. Fusarium oxysporum f. sp. eustomae causing wilting on lisianthus (Eustoma grandiflorum), Turnip mosaic virus causing mosaic and color breaking on stock, Cercospora spp. causing cercospora leaf spot on various wild lily, Cladosporum echinulatum causing leaf spot on carnation, and phytoplasma causing witches' broom on statice (Limonium sinuatum) and blazing star (Liatris spp.) were newly found during these surveys in Korea.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.232-242
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• 2017

The goal of marker-assisted backcrossing (MAB) is to significantly reduce the number of breeding generations required by using genome-based molecular markers to select for a particular trait; however, MAB systems have only been developed for a few vegetable crops to date. Among the types of molecular markers, SNPs (single-nucleotide polymorphisms) are primarily used in the analysis of genetic diversity due to their abundance throughout most genomes. To develop a MAB system in Chinese cabbage, a high-throughput (HT) marker system was used, based on a previously developed set of 468 SNP probes (BraMAB1, Brassica Marker Assisted Backcrossing SNP 1). We selected a broad-spectrum TuMV (Turnip mosaic virus) resistance (trs) Chinese cabbage line (SB22) as a donor plant, constructing a $BC_1F_1$ population by crossing it with the TuMV-susceptible 12mo-682-1 elite line. Foreground selection was performed using the previously developed trsSCAR marker. Background selection was performed using 119 SNP markers that showed clear polymorphism between donor and recipient plants. The background genome recovery rate (% recurrent parent genome recovery; RPG) was good, with three of 75 $BC_1F_1$ plants showing a high RPG rate of over 80%. The background genotyping result and the phenotypic similarity between the recurrent parent and $BC_1F_1$ showed a correlation. The plant with the highest RPG recovery rate was backcrossed to construct the $BC_2F_1$ population. Foreground selection and background selection were performed using 169 $BC_2F_1$ plants. This study shows that, using MAB, we can recover over 90% of the background genome in only two generations, highlighting the MAB system using HT markers as a highly efficient Brassica rapa backcross breeding system. This is the first report of the application of a SNP marker set to the background selection of Chinese cabbage using HT SNP genotyping technology.