RESUMO
Potato yellowing virus (PYV, original code SB-22), an unassigned member of the Genus Ilarvirus Family Bromoviridae, has been reported infecting potatoes in Peru, Ecuador and Chile. It is associated with symptomless infections, however yellowing of young leaves has been observed in some potato cultivars. Thirteen potato and yacon isolates were selected after routine screening of CIP-germplasm and twenty-four were identified from 994 potato plants collected in Peru whereas one was intercepted from yacon in the UK. These isolates were identified using high throughput sequencing, ELISA, host range and RT-PCR. Here we report the sequence characterization of the complete genomes of nine PYV isolates found infecting Solanum tuberosum, four complete genome isolates infecting Smallanthus sonchifolius (yacon), and in addition 15 complete RNA3 sequences from potato and partial sequences of RNA1, 2 and 3 of isolates infecting potato and yacon from Ecuador, Peru and Bolivia. Results of phylogenetic and recombination analysis showed RNA3 to be the most variable among the virus isolates and suggest potato infecting isolates have resulted through acquisition of a movement protein variant through recombination with an unknown but related ilarvirus, whereas one yacon isolate from Bolivia also had resulted from a recombination event with another related viruses in the same region. Yacon isolates could be distinguished from potato isolates by their inability to infect Physalis floridana, and potato isolates from Ecuador and Peru could be distinguished by their symptomatology in this host as well as phylogenetically. The non-recombinant yacon isolates were closely related to a recently described isolate from Solanum muricatum (pepino dulce), and all isolates were related to Fragaria chiloensis latent virus (FCiLV) reported in strawberry from Chile, and probably should be considered the same species. Although PYV is not serologically related to Alfalfa mosaic virus (AMV), they are both transmitted by aphids and share several other characteristics that support the previous suggestion to reclassify AMV as a member in the genus Ilarvirus.
Assuntos
Afídeos/virologia , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala , Especificidade de Hospedeiro , Ilarvirus/genética , Doenças das Plantas/virologia , Animais , Ilarvirus/classificação , Ilarvirus/isolamento & purificação , Filogenia , Folhas de Planta/virologia , Recombinação Genética , Solanum tuberosum/virologia , América do Sul , Reino UnidoRESUMO
As part of an initiative to characterize viruses infecting Cape gooseberry in the province of Antioquia (Colombia), we report the genome sequence of a new member of the genus Ilarvirus (family Bromoviridae). This virus was identified in a Cape gooseberry plot in the municipality of Marinilla in a mixed infection with potato virus Y (PVY) as part of high-throughput sequencing initiative. Results were confirmed by nested RT-PCR and DAS-ELISA. Phylogenetic analysis suggested that the Cape gooseberry ilarvirus is a new member of subgroup 1 and it is most closely related to ageratum latent virus (AgLV). The name "Cape gooseberry ilarvirus 1" (CGIV-1) is proposed for this new ilarvirus.
Assuntos
Genoma Viral , Ilarvirus/genética , Physalis/virologia , Doenças das Plantas/virologia , Potyvirus/genética , Mapeamento Cromossômico , Coinfecção , Colômbia , Efeito Fundador , Sequenciamento de Nucleotídeos em Larga Escala , Ilarvirus/classificação , Ilarvirus/isolamento & purificação , Filogenia , Potyvirus/classificação , Potyvirus/isolamento & purificaçãoRESUMO
Prunus necrotic ringspot virus (PNRSV) is distributed worldwide, but no molecular data have been previously reported from South American isolates. The nucleotide sequences corresponding to the movement (MP) and coat (CP) proteins of 23 isolates of PNRSV from Chile, Brazil, and Uruguay, and from different Prunus species, have been obtained. Phylogenetic analysis performed with full-length MP and CP sequences from all the PNRSV isolates confirmed the clustering of the isolates into the previously reported PV32-I, PV96-II and PE5-III phylogroups. No association was found between specific sequences and host, geographic origin or symptomatology. Comparative analysis showed that both MP and CP have phylogroup-specific amino acids and all of the motifs previously characterized for both proteins. The study of the distribution of synonymous and nonsynonymous changes along both open reading frames revealed that most amino acid sites are under the effect of negative purifying selection.