RESUMO
A putative new virus with sequence similarity to members of the genus Cavemovirus in the family Caulimoviridae was identified in wild chicory (Cichorium intybus) by next-generation sequencing (NGS). The putative new virus was tentatively named "chicory mosaic cavemovirus" (ChiMV), and its genome was determined to be 7,775 nucleotides (nt) long with the typical genome organization of cavemoviruses. ORF1 encodes a putative coat protein/movement polyprotein (1,278 aa), ORF2 encodes a putative replicase (650 aa), and ORF3 encodes a putative transactivator factor (384 aa). The first two putative proteins have 46.2% and 68.7% amino acid sequence identity to the CP/MP protein (YP_004347414) and replicase (YP_004347415), respectively, of sweet potato collusive virus (SPCV). ORF3 encodes a protein with 38.5% amino acid sequence identity to the putative transactivator factor (NP_056849) of cassava vein mosaic virus (CsVMV). The new putative viral genome and those of three cavemoviruses (epiphyllum virus 4 [EpV-4], SPCV, and CsVMV) differ by 24-27% in the nt sequence of the replicase gene, which exceeds the species demarcation cutoff (>20%) for the family.
Assuntos
Caulimoviridae/genética , Cichorium intybus/virologia , Sequência de Aminoácidos , Caulimoviridae/classificação , Genoma Viral/genética , Fases de Leitura Aberta/genética , Filogenia , Doenças das Plantas/virologia , Folhas de Planta/virologia , RNA Viral/genética , Especificidade da Espécie , Proteínas Virais/genéticaRESUMO
Here, we report the genome sequence and evidence for transcriptional activity of a virus-like element in the native Chilean berry tree Aristotelia chilensis. We propose to name the endogenous sequence as Aristotelia chilensis Virus 1 (AcV1). High-throughput sequencing of the genome of this tree uncovered an endogenous viral element, with a size of 7122 bp, corresponding to the complete genome of AcV1. Its sequence contains three open reading frames (ORFs): ORFs 1 and 2 shares 66%-73% amino acid similarity with members of the Caulimoviridae virus family, especially the Petunia vein clearing virus (PVCV), Petuvirus genus. ORF1 encodes a movement protein (MP); ORF2 a Reverse Transcriptase (RT) and a Ribonuclease H (RNase H) domain; and ORF3 showed no amino acid sequence similarity with any other known virus proteins. Analogous to other known endogenous pararetrovirus sequences (EPRVs), AcV1 is integrated in the genome of Maqui Berry and showed low viral transcriptional activity, which was detected by deep sequencing technology (DNA and RNA-seq). Phylogenetic analysis of AcV1 and other pararetroviruses revealed a closer resemblance with Petuvirus. Overall, our data suggests that AcV1 could be a new member of Caulimoviridae family, genus Petuvirus, and the first evidence of this kind of virus in a fruit plant.
Assuntos
Caulimoviridae/classificação , Caulimoviridae/isolamento & purificação , Elaeocarpaceae/virologia , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala , Caulimoviridae/genética , Análise por Conglomerados , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , Proteínas do Movimento Viral em Plantas/genética , DNA Polimerase Dirigida por RNA/genética , Ribonuclease H/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Transcrição Gênica , Integração ViralRESUMO
Virion purification from indicator plants and partial sequencing of the replicase region of a 'sweet potato caulimo-like virus' (SPCV) isolate from Madeira, Portugal, are described. Phylogenetic analysis suggests that SPCV is a distinct member of the genus Cavemovirus (family Caulimoviridae). These results explain previous failed attempts to characterize SPCV based on antibodies or primers designed for other members of the Caulimoviridae. Using a quick DNA extraction protocol and PCR primers flanking the RT motif region, we were able to detect SPCV directly in sweet potato, thus saving considerable time during routine virus indexing.
Assuntos
Caulimoviridae/classificação , Caulimoviridae/genética , DNA Polimerase Dirigida por DNA/genética , Ipomoea batatas/virologia , Análise por Conglomerados , DNA Viral/química , DNA Viral/genética , Dados de Sequência Molecular , Filogenia , Portugal , Análise de Sequência de DNA , Proteínas Virais/genéticaRESUMO
This study constitutes the first evaluation and application of quantitative taxonomy to the family Caulimoviridae and the first in-depth phylogenetic study of the family Caulimoviridae that integrates the common origin between LTR retrotransposons and caulimoviruses. The phylogenetic trees and PASC analyses derived from the full genome and from the corresponding partial RT concurred, providing strong support for the current genus classification based mainly on genome organisation and use of partial RT sequence as a molecular marker. The PASC distributions obtained are multimodal, making it possible to distinguish between genus, species and strain. The taxonomy of badnaviruses infecting banana (Musa spp.) was clarified, and the consequence of endogenous badnaviruses on the genetic diversity and evolution of caulimoviruses is discussed. The use of LTR retrotransposons as outgroups reveals a structured bipolar topology separating the genus Badnavirus from the other genera. Badnaviruses appear to be the most recent genus, with the genus Tungrovirus in an intermediary position. This structuring intersects the one established by genomic and biological properties and allows us to make a correlation between phylogeny and biogeography. The variability shown between members of the family Caulimoviridae is in a similar range to that reported within other DNA and RNA plant virus families.