RESUMO
Ornithogalum thyrsoides, a widely cultivated bulbous ornamental plant endemic to South Africa, has significant commercial value as a pot plant and for the production of cut flowers. However, infection by viruses threatens the success of commercial cultivation, as symptoms negatively affect the appearance of the plant and flowers. To date, four Ornithogalum-infecting viruses have been reported. Complete genome sequence data are available for three of these viruses, but the genome of the potyvirus ornithogalum virus 3 (OV3) has not been fully sequenced. In this study, the complete sequence of OV3 was determined by high-throughput sequencing (HTS) and validated by Sanger sequencing. Based on recognition of protease cleavage patterns and multiple sequence alignments with closely related viruses, the polyprotein of OV3 was predicted to be proteolytically cleaved to produce 10 mature peptides containing domains conserved in members of the genus Potyvirus. Phylogenetic analysis and species demarcation criteria confirm the previous classification of OV3 as a member of a separate species in this genus. This is the first report of a complete genome sequence of OV3.
Assuntos
Genoma Viral/genética , Ornithogalum/virologia , Doenças das Plantas/virologia , Potyvirus/genética , Sequência de Aminoácidos , Filogenia , Poliproteínas/genética , Potyvirus/classificação , Potyvirus/isolamento & purificação , RNA Viral/genética , África do Sul , Proteínas Virais/genéticaRESUMO
Ornithogalum thyrsoides, commonly known as chincherinchee, is an indigenous ornamental plant widely cultivated in South Africa. It is commercially valued as a flowering pot plant and for the production of cut flowers. Virus infections resulting in the development of severe necrotic mosaic symptoms threaten the success of commercial cultivation. The virome of an O. thyrsoides plant displaying necrotic mosaic symptoms was determined using high-throughput sequencing (HTS). In this plant, ornithogalum mosaic virus and ornithogalum virus 3 were identified, as well as a previously unknown virus. The full genome sequence of this virus was confirmed by Sanger sequencing using overlapping amplicons combined with rapid amplification of cDNA ends (RACE). Based on genome organisation and phylogenetic analysis, this novel virus can be classified as a polerovirus.
Assuntos
Genoma Viral , Luteoviridae/genética , Ornithogalum/virologia , Doenças das Plantas/virologia , Sequenciamento Completo do Genoma , Biologia Computacional , Ordem dos Genes , Sequenciamento de Nucleotídeos em Larga Escala , Luteoviridae/classificação , Luteoviridae/isolamento & purificação , Filogenia , África do SulRESUMO
Species of three viral genera infecting Ornithogalum thyrsoides plants showing mosaic symptoms were identified using RT-PCR and degenerate universal primers for each viral genus. The DNA fragments obtained encoded the coat protein (CP) gene and were sequenced. The plants were found to be infected with one or other of three potyvirus species, one of them was Ornithogalum mosaic virus (OrMV). The other two viruses were previously unrecorded and were named Ornithogalum virus 2 (OV-2) and 3 (OV-3). Direct comparison and phylogenetic analysis with published OrMV isolates revealed that the CP of the three OrMV-like clones were more similar to Pterostylis virus Y (PtVY) than to OrMV. No carlavirus or potexvirus was isolated.
