ABSTRACT
A new member of the genus Closterovirus was detected in Platycodon grandiflorus using high-throughput RNA sequencing analysis. The complete genome sequence of this new virus isolate, tentatively named "platycodon closterovirus 1" (PlaCV1), comprises 16,771 nucleotides with nine predicted open reading frames (ORFs) having the typical closterovirus genome organization. PlaCV1 shares 37%-50% nucleotide sequence identity with other known closterovirus genome sequences. The putative RNA-dependent RNA polymerase (RdRp), heat shock protein 70-like protein (HSP70h), viral heat shock protein 90-like protein (HSP90h), minor coat protein (CPm), and coat protein (CP) show 47-68%, 39-66%, 24-52%, 21-57%, and 16-35% amino acid sequence identity, respectively, to homologous proteins in previously identified closteroviruses, suggesting that it represents a distinct, new species in the genus. Phylogenetic analysis of HSP70h sequences places PlaCV1 alongside other members of the genus Closterovirus in the family Closteroviridae. To our knowledge, this study is the first report of the complete genome sequence of PlaCV1 infecting P. grandiflorus in the Republic of Korea.
Subject(s)
Closterovirus/genetics , Genome, Viral/genetics , Plant Diseases/virology , Platycodon/virology , Amino Acid Sequence , Base Sequence , High-Throughput Nucleotide Sequencing/methods , Open Reading Frames/genetics , Phylogeny , RNA, Viral/genetics , Republic of Korea , Viral Proteins/genetics , Whole Genome Sequencing/methodsABSTRACT
The complete genome sequence of a new virus, provisionally named "balloon flower endornavirus" (BfEV), was determined following virus isolation from leaves of a balloon flower (Platycodon grandiflorum) exhibiting severe leaf shrinkage disease in Anhui Province, China. The 15,180-nucleotide genome sequence of BfEV shares 40.52% amino acid (aa) sequence identity and 98% coverage with the polyprotein of Helianthus annuus endornavirus (HaEV). The open reading frame (ORF) encodes a deduced 4,887-aa polyprotein with RNA-dependent RNA polymerase (RdRp), viral helicase (Hel) and glycosyltransferase (GT) domains. Phylogenetic analysis of the amino acid sequences of RdRp places BfEV alongside members of the genus Alphaendornavirus in the family Endornaviridae. To our knowledge, this is the first report of a complete genome sequence of a novel alphaendornavirus identified in balloon flower.
Subject(s)
Plant Diseases/virology , Platycodon/virology , RNA Viruses/isolation & purification , Base Sequence , China , Genome, Viral , Open Reading Frames , Plant Leaves/virology , RNA Viruses/classification , RNA Viruses/genetics , Viral Proteins/geneticsABSTRACT
The complete 9,556-nt genomic sequence of a putative new potyvirus, tentatively named "platycodon mild mottle virus" (PlaMMV), infecting Platycodon grandiflorum was determined (GenBank accession no. MH779625). A single large open reading frame (ORF; nt 121-9360, 3079 aa) encoding a polyprotein that was predicted to be cleaved into 10 mature proteins was detected. By comparison with other potyviruses, nine cleavage sites and conserved domains/motifs were identified. PlaMMV also has a highly conserved GA6 motif (nt 2857-2863) that could enable a small overlapping ORF (PIPO) embedded within the P3 cistron to be translated by a viral polymerase slippage mechanism. A BLAST analysis showed that the complete PlaMMV nucleotide sequence shared 70% identity (40% query coverage) with carrot thin leaf virus (JX156434) and that the complete amino acid sequence of the PlaMMV polyprotein shared 54% identity (98% query coverage) with Thunberg fritillary mosaic virus (CAI59123). These results suggest that PlaMMV is a new member of the genus Potyvirus in the family Potyviridae.
