RESUMEN
Naranjilla (Solanum quitoense Lam.) and tamarillo (S. betaceum Cav.) are two important perennial solanaceous crops grown in Ecuador for the fresh market and juice production. Viruses infecting tamarillo and naranjilla are currently poorly studied, and no clean stock program exists in Ecuador. Here, we report a new virus, provisionally named as naranjilla mild mosaic virus (NarMMV) (genus Tymovirus, family Tymoviridae), isolated from naranjilla grown in an orchard in Pichincha Province, Ecuador. The complete genome of the virus consists of 6,348 nucleotides and encodes three open reading frames typical for members of the genus Tymovirus. Phylogenetically, Chiltepin yellow mosaic virus, Eggplant mosaic virus, and the recently characterized naranjilla chlorotic mosaic virus (NarCMV) were found to be the closest relatives of NarMMV. Unlike NarCMV, the new virus induced mild mosaic in naranjilla and more severe symptoms in tamarillo. Similar to NarCMV, NarMMV was unable to systemically infect potato. Virus surveys found NarMMV prevalent in naranjilla production areas of two provinces of Ecuador, especially where hybrid cultivars of naranjilla were cultivated. NarMMV was also found in field-grown tamarillo. The new virus cross-reacted with antibodies developed against NarCMV. Hence, this antibody will be useful for its field diagnosis using enzyme-linked immunosorbent assay or immunocapture reverse transcription polymerase chain reaction in future virus-free certification programs.
Asunto(s)
Solanum , Tymovirus , Ecuador , Genoma Viral/genética , Filogenia , Prevalencia , Solanum/virología , Tymovirus/clasificación , Tymovirus/genética , Tymovirus/fisiologíaRESUMEN
In a previous work, a distinct tymovirus infecting tomato plants in Brazil was reported and tentatively named tomato blistering mosaic virus (ToBMV). In this study, the complete genome sequence of ToBMV was determined and shown to have a size of 6277 nucleotides and three ORFs: ORF 1 encodes the replication-complex polyprotein, ORF 2 the movement protein, and ORF 3 the coat protein. The cleavage sites of the replication-complex polyprotein (GS/LP and VAG/QSP) of ToBMV were predicted by alignment analysis of amino acid sequences of other tymoviruses. In the phylogenetic tree, ToBMV clustered with the tymoviruses that infect solanaceous hosts.
Asunto(s)
Enfermedades de las Plantas/virología , Solanum lycopersicum/virología , Tymovirus/genética , Secuencia de Aminoácidos , Secuencia de Bases , Mapeo Cromosómico , Genoma Viral/genética , Datos de Secuencia Molecular , Sistemas de Lectura Abierta/genética , Filogenia , ARN Viral/genética , Alineación de Secuencia , Análisis de Secuencia de ARN , Tymovirus/clasificaciónRESUMEN
The complete genomic RNA sequences of the tymovirus isolates Hu and Col from potato which originally had been considered to be strains of the same virus species, i.e. Andean potato latent virus (APLV), were determined by siRNA sequencing and assembly, and found to share only c. 65% nt sequence identity. This result together with those of serological tests and comparisons of the coat protein gene sequences of additional tymovirus isolates from potato suggest that the species Andean potato latent virus should be subdivided into two species, i.e. APLV and Andean potato mild mosaic virus (APMMV). Primers were designed for the broad specificity detection of both viruses.
Asunto(s)
Genoma Viral , ARN Viral/genética , Análisis de Secuencia de ADN , Solanum tuberosum/virología , Tymovirus/genética , Análisis por Conglomerados , Datos de Secuencia Molecular , Filogenia , Homología de Secuencia , Tymovirus/clasificación , Tymovirus/aislamiento & purificaciónRESUMEN
A tymovirus was isolated in Brazil from tomato plants with severe symptoms of leaf mosaic and blistering. The virus was mechanically transmissible to solanaceous indicator host species. The infected plants contained icosahedral particles and chloroplasts with membrane deformations which are typical cytopathic effects caused by tymoviruses. Its coat protein amino acid sequence shares the maximum of 64 % identity with the tymovirus Chiltepin yellow mosaic virus, which suggested that it can be considered as a distinct member of the genus Tymovirus. In a phylogenetic tree, this tymovirus was clustered with other solanaceous-infecting tymoviruses. It was tentatively named as Tomato blistering mosaic virus (ToBMV).
Asunto(s)
Enfermedades de las Plantas/virología , Solanum lycopersicum/virología , Tymovirus/clasificación , Tymovirus/aislamiento & purificación , Brasil , Proteínas de la Cápside/genética , Análisis por Conglomerados , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Tymovirus/genéticaRESUMEN
Leaves of Cassia hoffmannseggii, a wild fabaceous species found in the Atlantic Forest, with a severe mosaic symptom were collected in Pernambuco State, Brazil. By transmission electron microscopy, two types of virus particles were found: the first was recognized as particles of a potyvirus, which was later identified as Cowpea aphid-borne mosaic virus; and the second was isometric and present in high concentration. The observation of vesicles at the periphery of chloroplasts suggested a tymovirus infection, which was confirmed by subsequent assays. A serological assay against several tymovirus antisera resulted in positive reaction of this tymo-like virus with an antiserum of Passion fruit yellow mosaic virus. By means of RT-PCR and using degenerated primers for the conserved region of RNA-dependent RNA polymerase (RdRp) gene of tymoviruses, a specific DNA fragment was amplified and sequenced. Based on this sequence, a specific forward primer was synthesized and successfully used to amplify the 3' terminal genome region, containing the partial RdRp gene and the complete coat protein (CP) sequences. The CP was 188 amino acids (aa) long, and the highest CP aa identity was observed with Kennedya yellow mosaic virus (61 %). Based on the current ICTV demarcation criterion, this isolate was considered as a distinct tymovirus and tentatively named as Cassia yellow mosaic-associated virus.
Asunto(s)
Cassia/virología , Enfermedades de las Plantas/virología , Hojas de la Planta/virología , Tymovirus/genética , Brasil , Proteínas de la Cápside/genética , Cassia/clasificación , Cartilla de ADN , Filogenia , ARN Viral/genética , ARN Polimerasa Dependiente del ARN/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Tymovirus/clasificación , Tymovirus/aislamiento & purificaciónRESUMEN
The characterization of viruses infecting wild plants is a key step towards understanding the ecology of plant viruses. In this work, the complete genomic nucleotide sequence of a new tymovirus species infecting chiltepin, the wild ancestor of Capsicum annuum pepper crops, in Mexico was determined, and its host range has been explored. The genome of 6,517 nucleotides has the three open reading frames described for tymoviruses, putatively encoding an RNA-dependent RNA polymerase, a movement protein and a coat protein. The 5' and 3' untranslated regions have structures with typical signatures of the tymoviruses. Phylogenetic analyses revealed that this new virus is closely related to the other tymoviruses isolated from solanaceous plants. Its host range is mainly limited to solanaceous species, which notably include cultivated Capsicum species. In the latter, infection resulted in a severe reduction of growth, indicating the potential of this virus to be a significant crop pathogen. The name of chiltepin yellow mosaic virus (ChiYMV) is proposed for this new tymovirus.