RESUMO
We isolated and compared three tomato spotted wilt virus (TSWV) isolates from lettuce (TSWV-Let), pepper (TSWV-Pep), and tomato (TSWV-Tom) from central Mexico to determine their ability to infect a set of eighteen differential plant species from seven families. TWSV-Let was an aggressive isolate with the ability to infect up to 52% of the differential plants, including maize, under greenhouse conditions. The nucleotide (nt) sequences of the three isolates are more than 90% similar in the M and S RNA segments. In the M segment of the TSWV-Let isolate, we detected nt changes in their intergenic region (IGR) and, in the Gc gene, a region containing a recombination site, as well as a synapomorphy associated with one of three sites under positive selection with a change in one aa residue (a cysteine-to-valine mutation). We speculate on the association of these features in the Gc gene with host selection, adaptation, aggressiveness, and ability to infect maize plants.
Assuntos
Filogenia , Doenças das Plantas/virologia , Solanum lycopersicum/virologia , Tospovirus/genética , Genoma Viral/genética , Solanum lycopersicum/genética , Doenças das Plantas/genética , RNA Viral/genética , Recombinação Genética , Tospovirus/classificação , Tospovirus/patogenicidadeRESUMO
The Tomato chlorotic spot virus (TCSV) was first reported in the 1980s, having its occurrence limited to Brazil and Argentina. Due to an apparent mild severity in the past, molecular studies concerning TCSV were neglected. However, TCSV has disseminated over the USA and Caribbean countries. In Dominican Republic TCSV has been recently reported on important cultivated crops such as pepper and beans. In this work, we provide the first complete genome of a TCSV isolate from symptomatic plants in Dominican Republic, which was obtained by high-throughput sequencing. In addition, three dsRNA viruses from different virus families were identified coinfecting these plants Bell pepper endornavirus (BPEV), Southern tomato virus (STV) and Pepper cryptic virus 2 (PCV-2). Phylogenetic analysis showed that the Dominican Republic TCSV isolate has a close relationship with other TCSV isolates and a reassortant isolate between TCSV and Groundnut ringspot virus (GRSV), all found in USA. BPEV, STV and PCV-2 isolates from Dominican Republic were close related to corresponding American isolates. The possible biological implications of these virus-mixed infections are discussed.
Assuntos
Coinfecção , Genoma Viral , Doenças das Plantas/virologia , Vírus de RNA/classificação , Vírus de RNA/genética , Tospovirus/classificação , Tospovirus/genética , Verduras/virologia , República Dominicana , Sequenciamento de Nucleotídeos em Larga Escala , Fenótipo , Filogenia , Vírus de RNA/isolamento & purificação , RNA de Cadeia Dupla , RNA Viral , Tospovirus/isolamento & purificaçãoRESUMO
BACKGROUND: Zucchini lethal chlorosis virus (ZLCV) causes significant losses in the production of cucurbits in Brazil. This virus belongs to the genus Tospovirus (family Bunyaviridae) and seems to be exclusively transmitted by Frankliniella zucchini (Thysanoptera). Tospoviruses have a tripartite and single-stranded RNA genome classified as S (Small), M (Medium) and L (Large) RNAS. Although ZLCV was identified as a member of the genus Tospovirus in 1999, its complete genome had not been sequenced until now. FINDINGS: We sequenced the full-length genome of two ZLCV isolates named ZLCV-SP and ZLCV-DF. The phylogenetic analysis showed that ZLCV-SP and ZLCV-DF clustered with the previously reported isolate ZLCV-BR09. Their proteins were closely related, except the non-structural protein (NSm), which was highly divergent (approximately 90 % identity). All viral proteins clustered similarly in our phylogenetic analysis, excluding that these ZLCV isolates have originated from reassortment events of different tospovirus species. CONCLUSION: Here we report for the first time the complete genome of two ZLCV isolates that were found in the field infecting zucchini and cucumber.
Assuntos
Cucurbita/virologia , Genoma Viral , Doenças das Plantas/virologia , Tospovirus/isolamento & purificação , Sequência de Aminoácidos , Sequência de Bases , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Tospovirus/química , Tospovirus/classificação , Tospovirus/genética , Proteínas Virais/química , Proteínas Virais/genéticaRESUMO
Groundnut ringspot virus (GRSV) and tomato chlorotic spot virus (TCSV) share biological and serological properties, so their identification is carried out by molecular methods. Their genomes consist of three segmented RNAs: L, M and S. The finding of a reassortant between these two viruses may complicate correct virus identification and requires the characterization of the complete genome. Therefore, we present for the first time the complete sequences of all the genes encoded by a GRSV isolate. The high level of sequence similarity between GRSV and TCSV (over 90 % identity) observed in the genes and proteins encoded in the M RNA support previous results indicating that these viruses probably have a common ancestor.
Assuntos
Genoma Viral , Doenças das Plantas/virologia , Tospovirus/genética , Sequência de Bases , Genômica , Solanum lycopersicum/virologia , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Tospovirus/classificação , Tospovirus/isolamento & purificação , Proteínas Virais/genéticaRESUMO
We report the first complete nucleotide sequence of a tomato spotted wilt virus (genus Tospovirus, family Bunyaviridae) isolate from the United States. The tripartite genome of PA01 consisted of L, M and S RNAs of 8914, 4765 and 2984 nt, respectively. Similarity percentages in nucleotide and amino acid sequence among PA01 and previously characterized TSWV isolates are provided here. Phylogenetic analysis on the RNA-dependent RNA polymerase (RdRp) gene placed PA01 in a different clade from an isolate from Hawaii that was partially characterized previously. Evidence of two putative reassortment events in the M segment, among PA01 and isolates from South Korea, Italy and Brazil, was found by phylogenetic and recombination analysis, further supporting a role for genetic exchange among isolates of different geographic origin in TSWV evolution.
Assuntos
Genoma Viral , Doenças das Plantas/virologia , Solanum lycopersicum/virologia , Tospovirus/genética , Tospovirus/isolamento & purificação , Sequência de Bases , Brasil , Havaí , Itália , Dados de Sequência Molecular , Filogenia , República da Coreia , Tospovirus/classificação , Estados UnidosRESUMO
Two virus isolates, T1 and T2, causing necrotic spots on leaves and stems of pepper and tomato, respectively, were isolated in the La Joya valley, Arequipa, Peru, in 2010. These two isolates were inoculated to differential hosts for tospoviruses and showed differential fitness: T1 induced necrotic local lesions in Vigna unguiculata, whereas T2 produced only chlorotic spots. The complete nucleotide sequence of the small (S) RNA from T2 and 1863 bp of the S RNA from T1 were determined. The deduced N protein sequence showed high amino acid identity (97%) between the isolates, indicating that the T1 and T2 are isolates of the same virus. Sequence comparisons indicated that the amino acid sequence of the N protein shared 53.49-87.98% identity with known American tospoviruses. Phylogenetic analysis of both the NSs and N proteins revealed that this new tospovirus belongs to the American group. We conclude that this tospovirus should be considered a member of a new species. The name Pepper necrotic spot virus (PNSV) is proposed.
Assuntos
Doenças das Plantas/virologia , Solanaceae/virologia , Tospovirus/classificação , Tospovirus/isolamento & purificação , Análise por Conglomerados , Genoma Viral , Especificidade de Hospedeiro , Dados de Sequência Molecular , Peru , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Tospovirus/genética , Tospovirus/patogenicidade , Proteínas Virais/genéticaRESUMO
Tomato spotted wilt virus (TSWV) is well established in most countries worldwide, while it is rarely reported in China. In this report, we have determined the complete nucleotide sequence of a TSWV isolate named TSWV-YN infecting tomato in Yunnan province in southwestern China. The tripartite genome of TSWV-YN was found to consist of L, M and S RNAs of 8910, 4773 and 2970 nt, respectively. The complete genome sequence and the sequence of each genomic region of TSWV-YN from China were compared to those of four other TSWV isolates from Brazil and Korea. The phylogenetic relationship of the Chinese TSWV-YN isolate to other TSWV isolates of different geographic origin, based on the nucleotide sequences of the glycoprotein (GP) and nucleocapsid (N) genes, was also analyzed in this study.
Assuntos
Genoma Viral , Doenças das Plantas/virologia , Solanum lycopersicum/virologia , Tospovirus/genética , Tospovirus/isolamento & purificação , Sequência de Bases , Brasil , China , Coreia (Geográfico) , Dados de Sequência Molecular , Filogenia , Tospovirus/classificação , Proteínas Virais/genéticaRESUMO
The tospoviral RNA-dependent RNA polymerases (RdRp), or L proteins, perform several conserved functions during virus replication in host cells. In this study, an L segment sequence of 9,040 bp from a new tospovirus (family Bunyaviridae) naturally infecting bean (Phaseolus vulgaris L.) plants was characterized. It encodes the largest RdRp gene known yet for this genus, with deduced 2932aa and a molecular mass of approximately 336 kDa. A Lysine-rich C-terminal extension was found, which apart from our isolate, was only recognized in another recently discovered tospovirus infecting Fabaceae, Soybean vein necrosis associated virus (SVNaV). Due to its distinct biological features and L protein-based phylogenetic analysis showing an almost equidistant position in comparison to Eurasian and American Tospovirus groups, as well as the clustering with SVNaV, we suggest the tentative name Bean necrotic mosaic virus for this unique isolate.
Assuntos
Phaseolus/virologia , Doenças das Plantas/virologia , RNA Polimerase Dependente de RNA/genética , Tospovirus/enzimologia , Tospovirus/isolamento & purificação , Proteínas Virais/genética , Sequência de Aminoácidos , Brasil , Dados de Sequência Molecular , Filogenia , RNA Polimerase Dependente de RNA/química , Alinhamento de Sequência , Tospovirus/classificação , Tospovirus/genética , Proteínas Virais/químicaRESUMO
A tospovirus causing necrotic streaks on leaves was isolated from Alstroemeria sp. in Colombia. Infected samples reacted positively with tomato spotted wilt virus (TSWV) antiserum during preliminary serological tests. Further analysis revealed a close serological relationship to tomato chlorotic spot virus (TCSV) and groundnut ringspot virus (GRSV). A major part of the S-RNA segment, encompassing the nucleocapsid (N) protein gene, the 5' untranslated region and a part of the intergenic region 3' of the N gene, was cloned and sequenced. The deduced N protein sequence showed highest amino acid identity (82%) to that of TCSV, indicating that the virus represents a new tospovirus species, for which the name Alstroemeria necrotic streak virus (ANSV) is coined. Phylogenetic analysis based on the N protein sequence revealed that this Alstroemeria-infecting tospovirus clustered with tospoviruses from the American continent. Frankliniella occidentalis was identified as potential vector species for ANSV.
Assuntos
Alstroemeria/virologia , Doenças das Plantas/virologia , Tospovirus/classificação , Tospovirus/genética , Clonagem Molecular , Análise por Conglomerados , Colômbia , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Sorotipagem , Tospovirus/imunologia , Tospovirus/isolamento & purificação , Proteínas Virais/genéticaRESUMO
Two tospoviruses, Chrysanthemum stem necrosis virus (CSNV) and Zucchini lethal chlorosis virus (ZLCV), cause economical losses in several ornamental and vegetable crops in Brazil. The nucleocapsid gene and movement protein sequences had already been reported for both viruses, though the glycoprotein precursor gene sequence was not available. In this study, cDNA fragments (ca. 4 kb) of the M RNA 3' portion of CSNV (isolate Chry-1) and ZLCV (isolate 1038), including the complete glycoprotein precursor gene, partial NSm gene, and the entire intergenic and 3' untranslated regions, were cloned and sequenced. The sequences were assembled with the corresponding 5' region sequence (NSm gene and 5'UTR) of the same isolates to build up the complete sequence of the M RNA segment of both species. The M RNA of CSNV was 4,828 nucleotide-long, while of ZLCV 4,836 nucleotides. Both M RNA molecules comprised two ORFs in an ambisense arrangement. The vcRNA coded for the viral glycoprotein (Gn/Gc) precursor gene of CSNV and ZLCV (both with 127.5 kDa). Comparison of deduced amino acids of the CSNV and ZLCV glycoprotein precursor genes with those of other tospoviruses showed the highest identity with that of Tomato spotted wilt virus (86%) and with that of CSNV (82%), respectively. However, the nucleotide sequence of the intergenic and 3' untranslated regions of CSNV and ZLCV shared lower identities with other tospoviruses. The glycoprotein precursor gene is thought to be a good candidate as additional classification parameter for Tospovirus taxonomy. The presence of the RGD motif in both Gc proteins indicated that they are typical American tospoviruses, which was confirmed by phylogenetic analysis. The membrane topology of both glycoproteins is discussed.
Assuntos
Glicoproteínas/genética , Tospovirus/genética , Proteínas Virais/genética , Regiões 3' não Traduzidas/genética , Sequência de Aminoácidos , Clonagem Molecular , DNA Intergênico/genética , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Tospovirus/classificaçãoRESUMO
The tospoviruses Tomato chlorotic spot virus (TCSV) and Groundnut ringspot virus (GRSV) cause high economic losses in several vegetable crops in Brazil. The glycoprotein precursor coding sequence was still not available for these two viruses. In this study, the 3' 4 kb M RNA of TCSV and GRSV genome was cloned and sequenced. The sequences were compiled with the available 5' region sequence (NSM gene and 5' UTR) of the same isolates. The M RNA of TCSV was deduced as formed by 4,882 nucleotides, while of GRSV by 4,855 nucleotides. Both M RNA comprised two ORFs in an ambisense arrangement. The vcRNA ORF coded for viral glycoprotein (G1/G2) precursor of TCSV (128.46 kDa) and for glycoprotein precursor of GRSV (128.16 kDa). Comparison of the TCSV and GRSV glycoprotein precursor proteins with those of other tospoviruses showed the highest identity with Tomato spotted wilt virus (81 and 79%, respectively). The amino acid sequence comparison of glycoprotein precursor between TCSV and GRSV revealed a high identity of 92%. However, the nucleotide sequence of the M RNA intergenie region showed only 78%. Phylogenetic analysis was done based on glycoprotein precursor and on M RNA intergenic region of tospoviruses and parameters on tospovirus taxonomic classification were discussed.
Assuntos
Glicoproteínas de Membrana/genética , Tospovirus/genética , Proteínas Virais/genética , Regiões 3' não Traduzidas , Sequência de Bases , Brasil , Clonagem Molecular , DNA Intergênico , DNA Viral , Genes Virais , Dados de Sequência Molecular , Filogenia , Precursores de Proteínas/genética , RNA Mensageiro , RNA Viral , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido Nucleico , Especificidade da Espécie , Tospovirus/classificação , Tospovirus/isolamento & purificaçãoRESUMO
In order to determine the diversity of the movement protein (NS(M)) among tospoviruses, the NSM genes of five distinct tospovirus species occurring in Brazil (Tomato chlorotic spot virus, Groundnut ring spot virus, Chrysanthemum stem necrosis virus, Zucchini lethal chlorosis virus and Iris yellow spot virus) were cloned, sequenced and compared with NS(M) sequences of other available tospoviruses. The 'D-motif', a conserved region present in the majority of '30K superfamily' virus movement proteins, is present in all NSM amino acid sequences available. In addition to the 'D-motif', a conserved phospholipase A2 motif was found. The NSM amino acid sequence comparisons among tospovirus species revealed several conserved regions located in the internal part of the protein and diverse domains mainly located in the amino-terminus. Prediction of secondary structure showed similar patterns among all NS(M) proteins analyzed. Considering the geographical prevalence and phylogenetic analysis of N and NS(M) proteins, tospoviruses were tentatively clustered in 'American' and 'Eurasian' groups. Both phylogenetic trees may reflect the natural evolution of tospovirus species within distinct ecological niches. The sequence information obtained in this work would facilitate functional analysis of NS(M) during the tospovirus infection process.
Assuntos
Genes Virais , Tospovirus/genética , Proteínas não Estruturais Virais/genética , Proteínas Virais/genética , Sequência de Aminoácidos , Brasil , Clonagem Molecular , Dados de Sequência Molecular , Filogenia , Proteínas do Movimento Viral em Plantas , Estrutura Secundária de Proteína , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Tospovirus/classificação , Proteínas não Estruturais Virais/química , Proteínas Virais/químicaRESUMO
The genomic diversity of Argentine Tospoviruses from different geographical areas, and from several distinct crops was analysed here. For each isolate, RT-PCR, cloning and sequencing of a 450 nt fragment of the N gene were performed. Comparisons of RNA and predicted amino acid sequence identity and similarity were made. A partial sequence of the N gene was able to classify our local isolates within three Tospovirus species previously described (Tomato spotted wilt virus, TSWV; tomato chlorotic spot virus, TCSV and groundnut ringspot virus, GRSV). With the sequence data currently available, we performed a cladistic phylogenetic analysis which gave a possible genealogy among members of the Tospovirus genus.