• The Plant Pathology Journal
• /
• v.34 no.6
• /
• pp.514-531
• /
• 2018

Tomato spotted wilt virus (TSWV; Genus Orthotospovirus: Family Tospoviridae) is one of the most destructive viruses affecting a wide range of horticultural crops on a worldwide basis. In 2015 and 2016, 171 leaf and fruit samples from tomato (Solanum lycopersicum) plants with viral symptoms were collected from the fields in various regions of Iran. ELISA test revealed that the samples were infected by TSWV. The results of RT-PCR showed that the expected DNA fragments of about 819 bp in length were amplified using a pair of universal primer corresponding to the RNA polymerase gene and DNA fragments of ca 777 bp and 724 bp in length were amplified using specific primers that have been designed based on the nucleocapsid (N) and non-structural (NSs) genes, respectively. The amplified fragments were cloned into pTG19-T and sequenced. Sequence comparisons with those available in the GenBank showed that the sequences belong to TSWV. The high nucleotide identity and similarities of new sequences based on the L, N, and NSs genes showed that minor evolutionary differences exist amongst the isolates. The phylogenetic tree grouped all isolates six clades based on N and NSs genes. Phylogenetic analysis showed that the Iranian isolates were composed a new distinct clade based on a part of polymerase, N and NSs genes. To our knowledge, this is the first detailed study on molecular characterization and genetic diversity of TSWV isolates from tomato in Iran that could be known as new clade of TSWV isolates.

• Research in Plant Disease
• /
• v.29 no.3
• /
• pp.286-294
• /
• 2023

Biological and molecular characterization of a Korean isolate of Orthotospovirus chrysanthinecrocaulis (formerly known as chrysanthemum stem necrosis virus, CSNV) isolated from Chrysanthemum morifolium was determined using host range and sequence analysis in this study. Twenty-three species of indicator plants inoculated mechanically CSNV-Kr was investigated for determination of host range. CSNV-Kr induced various local and systemic symptoms in the inoculated plant species. CSNV-Kr could not infect three plant species and induced symptomless in systemic leaves in Nicotiana tabacum cultivars, though the plant samples reacted positively with the antiserum to CSNV by double-antibody sandwich-enzyme-linked immunosorbent assay. The complete genome sequence of CSNV-Kr was determined. The L RNA of CSNV-Kr consists of 8,959 nucleotides (nt) and encodes a putative RNA-dependent RNA polymerase. The M RNA of CSNV-Kr consists of 4,835 nt and encodes the movement protein (NSm) and the glycoprotein precursor (Gn/Gc protein). The S RNA of CNSV-Kr consists of 2,836 nt and encodes NSs protein and N protein. The Gn/Gc and N sequence of CSNV-Kr were compared with those of previously published CSNV isolates originating from different countries at nucleotide and amino acid levels. The Gn/GC sequence of CSNV-Kr shared 98.8-99.5% identity with CSNV isolated from other countries and the N sequence of CSNV-Kr shared 98.8-99.6% identity. No particular region of variability could be found in either grouping of viruses. All of the CSNV isolates did not show any relationship according to geographical origins and isolation hosts, suggesting no distinct segregation of the CSNV isolates.

• The Plant Pathology Journal
• /
• v.40 no.3
• /
• pp.310-321
• /
• 2024

Tomato yellow leaf curl virus (TYLCV) and tomato spotted wilt virus (TSWV) are well-known examples of the begomovirus and orthotospovirus genera, respectively. These viruses cause significant economic damage to tomato crops worldwide. Weeds play an important role in the ongoing presence and spread of several plant viruses, such as TYLCV and TSWV, and are recognized as reservoirs for these infections. This work applies a comprehensive approach, encompassing field surveys and molecular techniques, to acquire an in-depth understanding of the interactions between viruses and their weed hosts. A total of 60 tomato samples exhibiting typical symptoms of TYLCV and TSWV were collected from a tomato greenhouse farm in Nonsan, South Korea. In addition, 130 samples of 16 different weed species in the immediate surroundings of the greenhouse were collected for viral detection. PCR and reverse transcription-PCR methodologies and specific primers for TYLCV and TSWV were used, which showed that 15 tomato samples were coinfected by both viruses. Interestingly, both viruses were also detected in perennial weeds, such as Rumex crispus, which highlights their function as viral reservoirs. Our study provides significant insights into the co-occurrence of TYLCV and TSWV in weed reservoirs, and their subsequent transmission under tomato greenhouse conditions. This project builds long-term strategies for integrated pest management to prevent and manage simultaneous virus outbreaks, known as twindemics, in agricultural systems.

• Research in Plant Disease
• /
• v.28 no.4
• /
• pp.237-244
• /
• 2022

Chrysanthemum plants are one of the most economically important plants in South Korea. Both virus and viroid can cause diseases and economic damage to the plants. In this study, we investigated the detection of seven viruses and two viroids in 350 chrysanthemum plants cultivated in Yesan-gun, Chungcheongnam-do. Two viruses, chrysanthemum virus B (CVB) and tomato aspermy virus (TAV), and two viroids, chrysanthemum chlorotic mottle viroid (CChMVd) and chrysanthemum stunt viroid (CSVd), were detected in this study. The two viruses were detected in six samples and one sample, respectively. The two viroids were detected in 97 samples and 21 samples, respectively. The nucleotide sequences of the CVB-CN-Y, TAV-CN-Y, CChMVd-CN-Y, and CSVd-CN-Y obtained in this study showed 83.7-86.9%, 99.2-100.0%, 94.4-99.5%, and 95.7-99.7% identity, respectively, compared to their other strains/isolates. The CVB-CN-Y and TAV-CN-Y showed the greatest nucleotide sequence homology to CVB-GS1 and three TAV isolates (TAV-V, TAV-P, and TAV-ChJ), respectively. The CChMVd-CN-Y and CSVd-CN-Y showed the greatest nucleotide sequence homology to CChMVd-Horst and four CSVd isolates (Au1.1, K4pop, Sagae, and Tochigi), respectively. This study is the report on the infection rate of viruses and viroids in chrysanthemum plants cultivated in Yesan-gun in 2021.

• Research in Plant Disease
• /
• v.23 no.4
• /
• pp.383-387
• /
• 2017

In 2016, less than 30% of virus-like symptoms such as chlorosis, necrosis and ringspots were observed in Hoya carnosa from commercial greenhouse in Eumseong, Korea. A total of 6 samples from Hoya carnosa were collected both symptomatic and asymptomatic plants and tested for virus infection by RT-PCR of 3 viruses known to infect Hoya spp. including Tomato spotted wilt virus (TSWV), Impatiens necrotic spot virus (INSV) and Tomato chlorotic spot virus (TCSV). Three symptomatic samples were positives for INSV. Also, it was not the virus detected in three asymptomatic samples. To further confirm the presence of INSV, complete nucleocapsid (N) gene of the virus were amplified and sequenced from two samples. BLAST analysis of the consensus sequence showed that two isolates (INSV-Hy1 and -Hy2) shared nucleotide sequence identities of 99% with each other and 97-99% with other INSV isolates available in the GenbBank. Phylogenetic analysis showed that these isolates closely related to the INSV isolates from ornamental from China. This is the first report of INSV on Hoya carnosa from Korea.

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