Radish Mosaic Virus Research Articles

Reassortment of Infectious Clones of Radish Mosaic Virus Shows that Systemic Necrosis in Nicotiana benthamiana Is Determined by RNA1.

Three infectious clones of radish mosaic virus (RaMV) were generated from isolates collected in mainland Korea (RaMV-Gg) and Jeju Island (RaMV-Aa and RaMV-Bb). These isolates differed in sequences and pathogenicity. Examination of the wild-type isolates and reassortants between the genomic RNA1 and RNA2 of these three isolates revealed that severe symptoms were associated with RNA1 of isolates Aa or Gg causing systemic necrosis in Nicotiana benthamiana, or with RNA1 of isolate Bb for induction of veinal necrosis and severe mosaic symptoms in radish. Reverse transcription, followed by quantitative real-time PCR (Q-RT-PCR), results from infected N. benthamiana confirmed that viral RNA2 accumulation level was correlated to RaMV necrosis-inducing ability, and that the RNA2 accumulation level was mostly dependent on the origin of RNA1. However, in radish, Q-RT-PCR results showed more similar viral RNA2 accumulation levels regardless of the ability of the isolate to induce necrosis. Phylogenetic analysis of genomic RNAs sequence including previously characterized isolates from North America, Europe, and Asia suggest possible recombination within RNA1, while analysis of concatenated RNA1+RNA2 sequences indicates that reassortment of RNA1 and RNA2 has been more important in the evolution of RaMV isolates than recombination. Korean isolate Aa is a potential reassortant between isolates RaMV-J and RaMV-TW, while isolate Bb might have evolved from reassortment between isolates RaMV-CA and RaMV-J. The Korean isolates were shown to also be able to infect Chinese cabbage, raising concerns that RaMV may spread from radish fields to the Chinese cabbage crop in Korea, causing further economic losses.

Viruses infecting cool season crops in the northern Turkey.

Virus diseases of cool season vegetable crops (mainly cabbage, white and red head cabbage, broccoli, kale, radish, rocket salad, garden cress, and turnip) were surveyed in Bafra Plain, Turkey during winter 2017, and 2018. Leaf samples were collected from different species of the Brassicaceae family showing mosaic, mottling, necrotic spots, malformation, and chlorosis symptoms. These samples were tested for the presence of Cauliflower mosaic virus (CaMV), Cucumber mosaic virus (CMV), Beet western yellows virus (BWYV), Radish mosaic virus (RaMV), Turnip mosaic virus (TuMV), Turnip yellow mosaic virus (TYMV), and Turnip yellows virus (TuYV) by biological and serological methods. A total of 455 samples were collected from cole crop fields and tested for the seven viruses by double-antibody sandwich ELISA using specific polyclonal antibodies. According to the results, out of these, 7 % of the samples were infected by at least one of these viruses. TuMV was the most prevalent virus detected in cole crops. TuMV, CaMV, and CMV were detected in 3 %, 2 %, and 2 % of infected samples, respectively, and the infection rate of these three viruses changed significantly among Brassica species.

Cell Death Triggered by a Putative Amphipathic Helix of Radish mosaic virus Helicase Protein Is Tightly Correlated With Host Membrane Modification.

Systemic necrosis is one of the most severe symptoms caused by plant RNA viruses. Recently, systemic necrosis has been suggested to have similar features to a defense response referred to as the hypersensitive response (HR), a form of programmed cell death. In virus-infected plant cells, host intracellular membrane structures are changed dramatically for more efficient viral replication. However, little is known about whether this replication-associated membrane modification is the cause of the symptoms. In this study, we identified an amino-terminal amphipathic helix of the helicase encoded by Radish mosaic virus (RaMV) (genus Comovirus) as an elicitor of cell death in RaMV-infected plants. Cell death caused by the amphipathic helix had features similar to HR, such as SGT1-dependence. Mutational analyses and inhibitor assays using cerulenin demonstrated that the amphipathic helix-induced cell death was tightly correlated with dramatic alterations in endoplasmic reticulum (ER) membrane structures. Furthermore, the cell death-inducing activity of the amphipathic helix was conserved in Cowpea mosaic virus (genus Comovirus) and Tobacco ringspot virus (genus Nepovirus), both of which are classified in the family Secoviridae. Together, these results indicate that ER membrane modification associated with viral intracellular replication may be recognized to prime defense responses against plant viruses.

Construction of an infectious cDNA clone of radish mosaic virus, a crucifer-infecting comovirus

Radish mosaic virus (RaMV) is a crucifer-infecting comovirus that has been detected worldwide. Here, we report the successful construction of a full-length infectious cDNA clone of RaMV. The full-length cDNA clones corresponding to RNA1 and RNA2 of a Japanese isolate of RaMV were cloned into the pBlueScript plasmid or the binary vector pCAMBIA1301 downstream of the cauliflower mosaic virus 35S promoter. Mechanical inoculation or agroinoculation of Nicotiana benthamiana with these vectors resulted in systemic RaMV infections causing symptoms similar to those caused by the wild-type parental virus. The presence of progeny virus was verified by western blot analysis and electron microscopy.

2007-2011 우리나라 농업현장 임상진단 요청 작물의 바이러스 감염 특성

National Institute of Horticultural and Herbal Science, Horticultural and Herbal Environmental Division,Suwon 441-707, Korea(Received on September 11, 2012; Revised on October 11, 2012; Accepted on October 12, 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 5years from 2007. The total number of virus tests was 13,325. The number of species of viruses infected on thesubmitted crops was 21 in 2007, 15 in 2008, 23 in 2009, 21 in 2010 and 17 in 2011. The newly recorded viruseswere Tobacco leaf curl virus (TbLCV) in 2007, Tomato yellow leaf curl virus (TYLCV) in 2008, Impatiencenecrotic spot virus (INSV) and Radish mosaic virus (RaMV) in 2009, and Beet western yellows virus (BWYV) in2010. Forty virus species including Alfalfa mosaic virus were detected over 5 years. The ten most frequentlydetected virus species were Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), Tomato leaf curlvirus (TYLCV), Cucumber green mottle mosaic virus (CGMMV), Broad bean wilt virus 2 (BBWV2), Zucchiniyellow 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 fromagricultural 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 10crops and top 20 crops was 81.6% and 94.2%, respectively. Eight pepper infecting virus species includedCMV, and the average infection rate was 24.6% for CMV, 18.9% for PMMoV and 14.7% for TSWV. Sevenkinds of double infection were detected in pepper including BBWV2+CMV at 14.7% on average, and fourtypes of triple infection including BBWV2+CMV+PepMoV at 0.9% on average. Six virus species detected ontomato including TYLCV, and the average infection rate was 50.6% for TYLCV, 14.5% for TSWV and10.9% for Tobacco leaf curl virus (TbLCV). The mixed infection of CMV+TSWV on tomato was 3.9% onaverage and of Tomato mosaic virus (ToMV)+TYLCV was 0.4% on average. Five viruses detected onwatermelon 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 andWMV+ZYMV having an average infection rate of 0.7% and 5.0%, respectively. The average infection rateson melon were 77.6% for MNSV, 5.6% for CMV and 3.3% for WMV. Mixed infections of CMV+MNSVoccurred on melon with an average infection rate of 13.5%. Keywords : BBWV2, BWVY, CGMMV, CMV, MNSV, Plant virus, TYLCV, ZYMV

Phylogenetic and serological analysis of turnip ringspot virus and radish mosaic virus isolates

Turnip ringspot virus (TuRSV) has been proposed to be a member of a new species in the genus Comovirus. Its remarkable host-range similarity to radish mosaic virus (RaMV) may have led to its misrecognition in the past. Findings from both sequence analysis and serological tests support the assignment of TuRSV to a new comovirus species. In addition, phylogenetic analysis suggests that the two genome segments of some TuRSV isolates have a heterogeneous origin.

A Comovirus Infecting Rocket (Eruca sativa) in Brazil

AbstractA virus related to Radish mosaic virus and Turnip ringspot virus (TuRSV) was found infecting rocket plants in Brazil. Predicted amino acids from partial viral RNA sequences placed it closer to TuRSV. We describe here the identification and partial characterization of the first comovirus found infecting a crucifer species in Brazil.

First Report of Turnip ringspot virus in Field Mustard (Brassica chinensis) in Taiwan.

Crucifer crops (Brassica spp.) are important winter vegetables in Taiwan. Five viruses, including Turnip mosaic virus (TuMV), Cucumber mosaic virus (CMV), Radish mosaic virus (RaMV), Beet western yellows virus (BWYV), and Cauliflower mosaic virus (CaMV), have been detected in a range of domestic-grown crucifers during past decades (1). Field mustard plants (Brassica chinensis) showing mosaic in the leaves were collected in the ChiaYi area in December 2007. Spherical virus-like particles, approximately 30 nm in diameter, were readily observed in crude sap of symptomatic plants. Tests by ELISA failed to detect any of the aforementioned viruses. A spherical agent was isolated through mechanical inoculation onto Chenopodium quinoa, and a virus culture was established and inoculated mechanically back to the original host as well as other crucifers. Systemic mosaic appeared on inoculated B. campestris, B. chinensis, and B. juncea, whereas ringspots appeared on inoculated leaves of B. oleracea. Total RNA was extracted from symptomatic leaves and used for reverse transcription (RT)-PCR amplification using degenerate primers for comoviruses (2). Other successive fragments of RNAs 1 and 2 were amplified by specific or degenerate primers designed on the basis of sequences of published Turnip ringspot virus (TuRSV). The RNA 1 (GenBank Accession No. GU968732) and RNA 2 (No. GU968731) of the isolated virus consisted of 6,076 and 3,960 nucleotides, respectively. The number of nucleotides and the arrangement of open reading frames on both RNA 1 and RNA 2 were similar to those of comoviruses. Sequence analysis revealed that the nucleotide sequences of RNA 1 and RNA 2 shared 54.2 to 82.5% and 50.2 to 79.3% similarities, respectively, to those of comoviruses and were most similar to Turnip ringspot virus. The deduced peptides of large and small coat proteins (LCP and SCP) contain 375 amino acids (41.2 kDa) and 251 amino acids (28.5 kDa), respectively. The deduced amino acid sequences of RNA-dependent RNA polymerase (RdRp), LCP, and SCP share 92.0 to 94.5%, 93.1 to 93.3% and 87.3 to 89.6% similarity, respectively, to those of published TuRSV isolates, i.e., -B (GenBank Accession No. GQ222382), -M12 (No. FJ516746), and -Toledo (No. FJ712027) indicating that the newly isolated virus from field mustard in Taiwan is an isolate of TuRSV, hence TuRSV-TW. Comparison of LCP and SCP between current TuRSV-TW and Radish mosaic virus (RaMV; GenBank Accession No. AB295644) showed 74% similarity, which is below the species demarcation level of 75% (3), indicating its discrimination from RaMV. To our knowledge, this is the first report of the occurrence of TuRSV in Taiwan and in the subtropics.

Complete nucleotide sequence of the Toledo isolate of turnip ringspot virus

The complete genomic sequence of the Toledo isolate of the comovirus, turnip ringspot virus (TuRSV), was found to consist of 2 polyadenylated RNAs. RNA 1 is 6082 nucleotides long and encodes a single predicted polypeptide of 1860 amino acids. The predicted RNA 1 polyprotein contains the polypeptides for viral replication and proteolytic processing. RNA 2, that is 3985 nucleotides long, codes for a single predicted 1095 amino acid polypeptide containing the movement and coat proteins. Phylogenetic analysis indicates that TuRSV is most closely related to radish mosaic virus, and these crucifer-infecting pathogens form a distinct clade within the comoviruses.

Occurrence of Potato virus X on hybrid dock in Czech Republic

Hybrid dock of Uteush (Rumex patientia L. x Rumex tianschanicus A. Los., the family Polygonaceae) is a perspective high productive crop and in the last decade its farming area has continuously grown in Czech Republic. However, the introduction of this non-native perennial crop into a present plant production creates a new potential reservoir for some plant viruses. Also, the hybrid dock could become a host of currently uncommon or insignificant viruses. We screened two dock-farming localities situated in south-west and north-east part of the Czech Republic for the presence of potyviruses, potexviruses, and carlaviruses. In the south-west part of the country, we detected a high incidence of Potato virus X (PVX, the genus Potexvirus). In contrast, in the north-east part of the country we did not detect any dock plants infected with PVX. Next, two other viruses, Turnip yellow mosaic virus (TYMV) and Radish mosaic virus (RaMV) were mechanically inoculated and tested for their survival capacity and multiplication in the hybrid dock. Both viruses were detected 9 months after inoculation in the infected plants.

Complete nucleotide sequence of a California isolate of Radish mosaic virus

Complete nucleotide sequence of a California isolate of Radish mosaic virus

Turnip ringspot virus recognised on Chinese cabbage in Russia

The nucleotide sequence of the 3′-terminal part of the RNA1 genome segment of the M12 isolate of comovirus Turnip ringspot virus (TuRSV) was established. This isolate originated in 1989 in Moscow (Russia) from Chinese cabbage with Radish mosaic virus-like symptoms. Comparison of the M12 RNA polymerase amino acid sequence with that of Radish mosaic virus (RaMV) revealed significant differences; these proteins are of different length and are only about 75% identical. On the other hand, the amino acid sequence of the M12 RNA polymerase was more than 94% identical with that of TuRSV recently described in Toledo (USA). We conclude that TuRSV occurs in Europe as well as in America and probably represents a new species of the genus Comovirus.

Identification and Host Relations of Turnip ringspot virus, A Novel Comovirus from Ohio.

Viruslike chlorotic ring spot symptoms and line patterns of unknown origin were observed on a greenhouse-grown turnip plant. The suspected virus was mechanically transmissible to plants in the Brassicaceae. Electron microscopic analysis revealed icosahedral particles approximately 28 nm in diameter. Reverse transcriptase-polymerase chain reaction (RT-PCR) analyses suggested that the pathogen is a comovirus, an observation that was confirmed by analysis of portions of the genomic sequence. This virus was provisionally named Turnip ringspot virus (TuRSV). Based on the RNA 1 sequence, TuRSV is most similar to Radish mosaic virus, another pathogen that infects members of the Brassicaceae. Arabidopsis thaliana is susceptible to TuRSV, and 12 out of the 23 ecotypes studied showed symptoms when inoculated with the virus. TuRSV induced a variety of responses on ecotypes from death to no infection. Some ecotypes showed one or two rounds of symptom display followed by recovery when inoculated with TuRSV. About half of the ecotypes (11/23) analyzed showed no symptoms when inoculated with TuRSV. Col-0 plants showed no symptoms, and infectious virus was not recovered from systemic leaves, although it could be detected by RT-PCR. Col-0 plants harboring mutations impairing the ethylene, jasmonic acid, or salicylic acid signaling pathways did not show symptoms when inoculated with TuRSV.

Genome sequence of a Japanese isolate of Radish mosaic virus: the first complete nucleotide sequence of a crucifer-infecting comovirus

The complete nucleotide sequences of RNA1 and RNA2 of a Japanese isolate of Radish mosaic virus (RaMV-J), a crucifer-infecting comovirus, were determined. RNA1 is 6064 nucleotides long and encodes a 210-kDa polyprotein containing conserved motifs that are required for replication. RNA2 is 4020 nucleotides long and encodes a 123-kDa polyprotein containing the putative movement protein and two coat proteins. Comparisons of the encoded proteins confirmed that RaMV-J and a Czech RaMV isolate are isolates of the same species in the genus Comovirus. A phylogenetic analysis of RaMV-J and other comoviruses revealed that legume-infecting comoviruses constitute a single branch to which RaMV is distantly related.

Reservoir Weed Hosts for Turnip mosaic virus in Iran.

During the summer of 2003, weed samples of Rapistrum rugosum and Sisymbrium loeselii showing severe mosaic, malformation, and stunting were collected from cauliflower fields in Tehran Province of Iran. Using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with specific polyclonal antibodies, the samples were tested for the presence of Beet western yellows virus, Cauliflower mosaic virus, Radish mosaic virus, Turnip crinkle virus, Turnip mosaic virus (TuMV) (DSMZ, Braunschweig, Germany), Cucumber mosaic virus, and Tobacco mosaic virus (Sanofi Diagnostics Pasteur, Marnes-La-Coquette, France). Leaf extracts were used for mechanical inoculation and they produced chlorotic local lesions on Chenopodium amaranticolor, necrotic lesions on leaves and shoot apex necrosis on Nicotiana glutinosa, leaf deformation, mosaic, and stunting on Petunia hybrida, and severe mosaic, distortion, and stunting on Brassica rapa. These symptoms were similar to those that were described previously for TuMV (4). ELISA results showed that the original leaf samples and inoculated indicator plants reacted positively with TuMV antibodies, but not with antibodies for any of the other viruses listed above. Also, reverse transcription-polymerase chain reaction of total RNA extracted from the collected leaf samples using the universal primers for potyviruses (3) resulted in the amplification of two fragments of the expected sizes, approximately 700 and 1,700 bp. TuMV, a member of the genus Potyvirus in the family Potyviridae, is transmitted by aphids in a nonpersistent manner (4). This virus is geographically widespread with a wide host range that can infect 318 species in 156 genera of 43 plant families including, Brassicaceae, Chenopodiaceae, Asteraceae, Cucurbitaceae, and Solanaceae (2,4). R. rugosum and S. loeselii, two annual or biennial plants in the Brassicaceae family, were common and widely distributed in the fields surveyed. The presence of TuMV-infected weed hosts in cauliflower fields may impact disease management strategies. TuMV was first observed on stock plants (Matthiola sp.) in Iran (1). To our knowledge, this is the first report of natural occurrence of TuMV on weed hosts in Iran.

Occurrence of Radish mosaic virus on Cauliflower and Turnip Crops in Iran.

During the spring and summer of 2003, symptoms of mosaic, mottle, and crinkle were observed in cauliflower (Brassica oleracea) and turnip (Brassica rapa) fields in the Qazvin and Esfahan provinces of Iran, respectively. Leaf extracts of these plants, made infective by mechanical inoculation, caused necrotic local lesions on Chenopodium amaranticolor, chlorotic ring spot on Nicotiana tabacum cv. Samsun, and chlorotic local lesions followed by systemic mosaic on Brassica rapa (1). Using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and specific polyclonal antibodies (As-0120 and PV-0355) that were kindly prepared by S. Winter (DSMZ, Braunschweig, Germany), the samples were tested for the presence of Radish mosaic virus (RaMV) (family Comoviridae, genus Comovirus). ELISA results showed that the original leaf samples and inoculated indicator plants reacted positively to RaMV antibodies. RaMV has been reported in the United States, Japan, and Europe on turnip and other crucifers (1,2). To our knowledge, this is the first report of RaMV occurring in Iran.

Serological variability among European isolates of radish mosaic virus

Serological variability of radish mosaic virus (RaMV) isolates from white mustard, winter turnip rape, Camelina sativa and Chinese cabbage, collected in the Czech Republic and Russia, was studied using antisera against the Czech isolate RaMV1. In contrast to previous studies, reasonable serological differences were found between isolates from different locations and hosts, and even between neighbouring mustard plants in the field. Serological variability of European isolates was confirmed in extended experiments involving an Italian isolate, the American Type Strain (ATS) and its homologous antiserum. The results indicate that, in Europe, RaMV isolates may occur which differ both serologically and in host plant response, but no typical strains can be defined with the methods and isolates employed so far. Camelina sativa is reported as a new host of the virus.

The Radish Mosaic Virus—A New Virus for Bulgaria

ABSTRACTIn one plant Raphanus raphanistrum with mosaic symptoms the Radish mosaic virus (RaMV) was established for the first time in Bulgaria. This virus was identified by biological test, indexes for the stability of the sap “in vitro” serological agar-gel diffusion test and tests for transmission by aphids.

Radish mosaic virus VPg Characteristics and linkage with virion RNAs

Comoviruses have a bipartite RNA genome. It is suggested that a small protein, VPg, is covalently linked to both RNAs. We have found that both radish mosaic virus RNAs are linked to identical VPg molecules via a phosphodiester bond between their 5′-terminal nucleotides and a serine residue of VPg.

Variants of elisa in plant virus diagnosis

Variations of enzyme-linked immunosorbent assay (ELISA) were compared with respect to their ability to detect and to differentiate serologically related plant viruses. The broadest range of serologically related viruses was detected by an indirect ELISA on unprecoated plates. Coating the plates with F(ab') 2 fragments led to narrowing of the specificity in heterologous reactions of tymo-, tombusand tobamoviruses in indirect ELISA. With Andean potato latent virus (APLV) heterologous reactions were weaker on plates precoated with F(ab') 2 fragments than on those precoated with intact antibodies. Even on plates precoated with F(ab') 2 fragments the indirect ELISA detected a broader range of serologically related viruses than the direct double antibody sandwich method. Heterologous reactions in indirect ELISA procedures on plates precoated with either intact antibodies or F(ab') 2 fragments were always weaker than homologous reactions independent of the concentration of coating reactants and detecting antibodies. Attempts to differentiate closely related strains of APLV or radish mosaic virus by direct ELISA using F(ab') 2ments either for coating the plates or after labelling with alkaline phosphatase for detecting the trapped antigens failed. Under suitable conditions, the additional working step usually necessary for indirect ELISA could be avoided by using a short procedure which at low concentrations of detecting antibodies was more sensitive than the conventional procedure.