• The Plant Pathology Journal
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• v.25 no.1
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• pp.26-37
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• 2009

Tomato spotted wilt virus (TSWV) was identified from seven plants at two areas, Anyang and Dangjin, in Korea. The isolates of TSWV were seven as TSWV-KATm from tomato, TSWV-KAPo from potato, TSWV-KABal from balsam, TSWV-KACTm from cherry tomato and TSWV-KAIxe from Ixeris dentata at Anyang area, and TSWV-KDSe from sesame and TSWV-KDRP from red pepper at Dangjin area. Pathogenicity of seven TSWV isolates was various on the assay plants, and could not be grouped definitely. Three isolates of TSWV-KAIxe, TSWV-KACTm and TSWV-KABal had relatively narrower host ranges among the seven isolates. Percentage of nucleotide substitution in nucleotide sequences encoding nucleocapsid protein (NCP) was 1.2-1.7% among seven TSWV isolates and TSWV-KP. Korean TSWV isolates were divided into three groups by nucleotide homology or amino acid compositions. From the analysis of nucleotide sequences of Korean TSWV isolates compared with those of TSWV reported from other 5 countries including Japan, the Korean seven isolates of TSWV was grouped with German TSWV (D13926). No Korean TSWV isolates were grouped with those from The Netherlands, Brazil and USA.

• Research in Plant Disease
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• v.28 no.4
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• pp.231-236
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• 2022

Oxypetalum coeruleum, commonly known as Tweedia, is a perennial herbaceous plant of the Apocynaceae family native to southern Brazil and Uruguay. Tweedia plants are grown as one of the most popular ornamental flowers for floral arrangement in Korea. In May 2021, several tweedia plants in a single greenhouse in Gimje, Jeollabuk-do were found to show virus-like symptoms including necrotic rings, vein-clearing, chlorotic mottle, and mosaic on the leaves, and necrosis on the stems. Here, we have identified tomato spotted wilt virus (TSWV) in symptomatic tweedia leaves by applying high-throughput RNA sequencing. In the result, a single infection by TSWV was verified without mixed infections of different virus species. To confirm the presence of TSWV, a reverse transcription polymerase chain reaction was performed with a specific primer set to the N gene of TSWV. The complete genomic sequence of L, M, and S segments of TSWV 'Oxy' isolate were determined and deposited in GenBank under accession numbers LC671525, LC671638, and LC671639, respectively. In the phylogenetic tree analysis by maximum likelihood method, 'Oxy' isolate showed a high relationship with TSWV 'Gumi' isolate from Gerbera jamesonii in Gyeongsangbuk-do, Korea; for all three RNA segments. To our knowledge, this is the first report of TSWV infection of O. coeruleum in Korea.

• Research in Plant Disease
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• v.27 no.3
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• pp.120-127
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• 2021

Plant viruses cause significant yield losses, continuously compromising crop production and thus representing a serious threat to global food security. Tomato spotted wilt virus (TSWV) is the most harmful plant virus that mainly infects horticultural crops and has a wide host range. Reverse-transcription quantitative real-time PCR (RT-qPCR) has been widely used for detecting TSWV with high sensitivity, but its application is limited owing to the lack of standardization. Therefore, in this study, a sensitive and accurate reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) method was established for TSWV detection. Additionally, we compared the sensitivities of RT-qPCR and RT-ddPCR for TSWV detection. Specificity analysis of RT-ddPCR for TSWV showed no amplification for main pepper viruses and negative control. TSWV transcripts levels measured by RT-ddPCR and RT-qPCR showed a high degree of linearity; however, the former yielded results that were at least 10-fold more sensitive and detected lower TSWV copy numbers than the latter. Collectively, our findings show that RT-ddPCR provides improved analytical sensitivity and specificity for TSWV detection, making it suitable for identifying low TSWV concentrations in field samples.

• Research in Plant Disease
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• v.20 no.1
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• pp.15-20
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• 2014

A rapid, user-friendly and simple immune-chromatographic dipstick kit named 'rapid immune-gold strip' (RIGS) kit was developed in a novel single strip format to detect on-site detection of Tomato spotted wilt virus (TSWV). Immunoglobulin G (IgG) from polyclonal antisera raised in rabbits against TSWV was purified through protein-A affinity chromatography and then the purified TSWV-IgG was conjugated to colloidal gold nano-particles which served as a test line on nitrocellulose membrane. Protein A that non-specifically binds to TSWV antibody was used as a control line on the same strip. The diagnosis process with the TSWV-RIGS involves simply grinding the suspect plant sample in a bag that contains the extraction buffer and inserting the strip the bag. Results can be seen in 2-5 minutes. The flow of the complexes of gold particles coated with TSWV-IgG and a crude sap from TSWV-infected pepper, tobacco and tomato plants resulted in intensive color formed on the test lines proportional to the concentrations of TSWV. The RIGS-TSWV kit did not show any cross-reactions against other tomato-infecting viruses unrelated to TSWV. These results indicate that the TSWV-RIGS kit is highly sensitive and is not required for laboratory training and experience prior to testing. The TSWV-RIGS kit is suitable for on-site detection of suspect TSWV-infected plants as well as for laboratory diagnosis.

• Korean Journal of Environmental Biology
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• v.39 no.3
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• pp.319-328
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• 2021

Tomato spotted wilt virus (TSWV) is one of the most destructive viruses worldwide, which causes severe damage to economically important crops, such as pepper and tomato. In this study, we examined the molecular and biological characterization of a TSWV isolate (SW-TO2) infecting tomato and compared it to the recently reported isolates from boxthorn, butterbur, and angelica plants. The phylogenetic analysis based on the complete genome sequences confirmed that SW-TO2 was clustered with those of isolates from boxthorn and pepper in Korea with the maximum nucleotide identities ranging from 98% to 99%. We developed the bioassay method for screening TSWV resistance and tested some commercial pepper and tomato cultivars for resistance evaluation of four isolates of TSWV. TSWV resistance was evaluated as TSWV resistance when all the following three conditions were satisfied: first, when symptoms of necrotic spots or no symptoms were present in the inoculated leaves; second, when there were no symptoms in the upper leaves; and third, when the upper leaves were negative as a result of RT-PCR diagnosis.

• Research in Plant Disease
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• v.27 no.2
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• pp.84-90
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• 2021

In June 2019, Angelica acutiloba plants showing virus-like symptoms such as chlorotic local lesion and mosaic on the leaves were found in a greenhouse in Nonsan, South Korea. To identify the causal virus, we collected 6 symptomatic A. acutiloba leaf samples and performed reverse transcription polymerase chain reaction (RT-PCR) analysis using specific detection primers for three reported viruses including tomato spotted wilt virus (TSWV). RT-PCR results showed that five symptomatic samples were positive for TSWV. Mechanical sap inoculation of one of the collected TSWV isolate (TSWV-NS-AG28) induced yellowing, chlorosis and mosaic symptoms in A. acutiloba and necrotic local lesions and mosaic in Solanaceae species. Phylogenetic analysis based on the complete genome sequences showed that TSWV-NS-AG28 had a maximum nucleotide identity with TSWVNS-BB20 isolated from butterbur in Nonsan, South Korea. To our knowledge, this is the first report of TSWV infection in A. acutiloba.

• Research in Plant Disease
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• v.16 no.3
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• pp.232-237
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• 2010

Tomato spotted wilt virus (TSWV) was occurred on the three vegetables of egg plant (Solanum melongena), whole radish (Raphanus acanthiformis) and sugar loaf (Cichorium intybus) at Anyang area infested with TSWV. Whole radish was produced the symptoms of necrotic spots on the leaves, and necrosis and malformation on the roots by TSWV. Egg plant was induced the symptoms of typical multiple ring spots on the leaves and necrotic rings on the fruits. Sugar loaf was infected severely with the typical symptoms of ring spots on the leaves and stunt. The three isolates of TSWV could infect locally on the indicator plants of Chenopodium amaranticolor, C. quinoa and Nicotiana debney, and systemically on N. glutinosa, N. benthamiana and Datura stramonium. Two TSWV isolates from egg plant and sugar loaf were very similar in virulence. However, the virulence of TSWV from whole radish was very different as local infection on 5 Nicotiana species including N. tabacum 'Xanthi NC'.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.230-234
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• 2006

Tomato spotted wilt virus (TSWV) has been identified in commercial chrysanthemum cultivars in Korea. Nucleotide sequences of the N gene of TSWV-ch14 isolated from infected chrysanthemum were determined and deposited in GenBank under accession no. DQ453158. The symptoms consisted of dark colored leaf necrosis, black streaks along the stem, wilting of plant parts in 'Sinma'; and chlorotic spots, necrosis of axillary shoots and withering of leaves in 'Hwarang'. Electron micrographs of leaf preparation of Nicotiana rustica infected with TSWV-ch14 contained spherical particles around 85 nm in diameter. TSWV was identified from chrysanthemum by sequence determination of N nucleocapsid protein and virion observation by transmission electron microscope. This is the first reported observation on TSWV in chrysanthemum in Korea.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.67-75
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• 2020

Tomato spotted wilt virus (TSWV) is one of the plant viruses transmitted by thrips and causes severe economic damage to various crops. From 2008 to 2011, to identify natural host species of TSWV in South Korea, weeds and crops were collected from 5 regions (Seosan, Yesan, Yeonggwang, Naju, and Suncheon) where TSWV occurred and were identified as 1,104 samples that belong to 144 species from 40 families. According to reverse transcription-polymerase chain reaction, TSWV was detected from 73 samples from 23 crop species, 5 of which belonged to family Solanaceae. Additionally, 42 weed species were confirmed as natural hosts of TSWV with three different life cycles, indicating that these weed species could play an important role as virus reservoirs during no cultivation periods of crops. This study provides up-to-date comprehensive information for TSWV natural hosts in South Korea.

• Research in Plant Disease
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• v.26 no.4
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• pp.264-271
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• 2020

We have developed a simultaneous diagnostic method that can identify both the species of thrips and tomato spotted wilt virus (TSWV) that are problematic in chrysanthemum plants. This is a method of amplifying DNA by performing reverse transcription-polymerase chain reaction by simultaneously adding primers specific to TSWV coat protein (N) gene and primers specific to the internal transcribed spacer 2 region of Frankliniella occidentalis and F. intonsa using total nucleic acid extracted from one thrips. The sizes of DNA fragments for TSWV, F. occidentalis, and F. intonsa were 777, 287, and 367 bp, respectively. These results showed species identification of thrips and whether thrips carrying TSWV can be simultaneously confirmed. Further usefulness of the simultaneous diagnostic method was made from greenhouse survey at chrysanthemum greenhouses in Taean (Chungcheongnam-do) and Changwon (Gyeongsangnam-do) to investigate the identification of thrips species and the rate of thrips carrying TSWV. Of thrips collected from the greenhouses, 83.7% thrips was F. occidentalis and 72.9% F. occidentalis carried TSWV in Taean. Similarly, the diagnostic method showed that 92.2% thrips was F. occidentalis and 84.0% F. occidentalis carried TSWV in Changwon. These results confirm that F. occidentalis is a dominant thrips species and the thrips species plays a crucial role in the transmission of TSWV in chrysanthemum plants in the greenhouses. Taken together, this study showed a simple diagnostic method for thrips identification and epidemiological studies of the timing and spread of TSWV through thrips in chrysanthemum greenhouses in South Korea.