71 research outputs found
Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2016)
This article lists the changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in April 2016.
Changes to virus taxonomy (the Universal Scheme of Virus Classification of the International Committee on Taxonomy of Viruses [ICTV]) now take place annually and are the result of a multi-stage process. In accordance with the ICTV Statutes (http://www.ictvonline.org/statutes.asp), proposals submitted to the ICTV Executive Committee (EC) undergo a review process that involves input from the ICTV Study Groups (SGs) and Subcommittees (SCs), other interested virologists, and the EC. After final approval by the EC, proposals are then presented for ratification to the full ICTV membership by publication on an ICTV web site (http://www.ictvonline.org/) followed by an electronic vote. The latest set of proposals approved by the EC was made available on the ICTV website by January 2016 (https://talk.ictvonline.org/files/proposals/). A list of these proposals was then emailed on 28 March 2016 to the 148 members of ICTV, namely the EC Members, Life Members, ICTV Subcommittee Members (including the SG chairs) and ICTV National Representatives. Members were then requested to vote on whether to ratify the taxonomic proposals (voting closed on 29 April 2016)
Complete nucleotide sequences and genome organization of a cherry isolate of cherry leaf roll virus
The complete nucleotide sequence of cherry leaf roll virus (CLRV, genus Nepovirus) from a naturally infected cherry tree (Prunus avium cv. Bing) in North America was determined. RNA1 and RNA2 consist of 7,893 and 6,492 nucleotides, respectively, plus a poly-(A) tail. Each RNA encodes a single potential open reading frame. The first 657 nucleotides of RNA1 and RNA2 are 99% identical and include the 5′-UTR and the first 214 deduced amino acids of the polyproteins following the first of two in-frame start codons. Phylogenetic analysis reveals close relationships between CLRV and members of subgroup C of the genus Nepovirus
Recommended from our members
Creation of new order, Ortervirales, for 5 families of reverse-transcribing viruses
Ortervirales: A new viral order unifying five families of reverse-transcribing viruses
Reverse-transcribing viruses, which synthesize a copy of genomic DNA from an RNA template, are widespread in animals, plants, algae and fungi (1, 2).
Short ORF-Dependent Ribosome Shunting Operates in an RNA Picorna-Like Virus and a DNA Pararetrovirus that Cause Rice Tungro Disease
Rice tungro disease is caused by synergistic interaction of an RNA picorna-like virus Rice tungro spherical virus (RTSV) and a DNA pararetrovirus Rice tungro bacilliform virus (RTBV). It is spread by insects owing to an RTSV-encoded transmission factor. RTBV has evolved a ribosome shunt mechanism to initiate translation of its pregenomic RNA having a long and highly structured leader. We found that a long leader of RTSV genomic RNA remarkably resembles the RTBV leader: both contain several short ORFs (sORFs) and potentially fold into a large stem-loop structure with the first sORF terminating in front of the stem basal helix. Using translation assays in rice protoplasts and wheat germ extracts, we show that, like in RTBV, both initiation and proper termination of the first sORF translation in front of the stem are required for shunt-mediated translation of a reporter ORF placed downstream of the RTSV leader. The base pairing that forms the basal helix is required for shunting, but its sequence can be varied. Shunt efficiency in RTSV is lower than in RTBV. But in addition to shunting the RTSV leader sequence allows relatively efficient linear ribosome migration, which also contributes to translation initiation downstream of the leader. We conclude that RTSV and RTBV have developed a similar, sORF-dependent shunt mechanism possibly to adapt to the host translation system and/or coordinate their life cycles. Given that sORF-dependent shunting also operates in a pararetrovirus Cauliflower mosaic virus and likely in other pararetroviruses that possess a conserved shunt configuration in their leaders it is tempting to propose that RTSV may have acquired shunt cis-elements from RTBV during their co-existence
Structural Insights into Viral Determinants of Nematode Mediated Grapevine fanleaf virus Transmission
Many animal and plant viruses rely on vectors for their transmission from host to
host. Grapevine fanleaf virus (GFLV), a picorna-like virus from
plants, is transmitted specifically by the ectoparasitic nematode
Xiphinema index. The icosahedral capsid of GFLV, which
consists of 60 identical coat protein subunits (CP), carries the determinants of
this specificity. Here, we provide novel insight into GFLV transmission by
nematodes through a comparative structural and functional analysis of two GFLV
variants. We isolated a mutant GFLV strain (GFLV-TD) poorly transmissible by
nematodes, and showed that the transmission defect is due to a glycine to
aspartate mutation at position 297 (Gly297Asp) in the CP. We next determined the
crystal structures of the wild-type GFLV strain F13 at 3.0 Å and of
GFLV-TD at 2.7 Å resolution. The Gly297Asp mutation mapped to an exposed
loop at the outer surface of the capsid and did not affect the conformation of
the assembled capsid, nor of individual CP molecules. The loop is part of a
positively charged pocket that includes a previously identified determinant of
transmission. We propose that this pocket is a ligand-binding site with
essential function in GFLV transmission by X. index. Our data
suggest that perturbation of the electrostatic landscape of this pocket affects
the interaction of the virion with specific receptors of the nematode's
feeding apparatus, and thereby severely diminishes its transmission efficiency.
These data provide a first structural insight into the interactions between a
plant virus and a nematode vector
Secoviridae: a proposed family of plant viruses within the order Picornavirales that combines the families Sequiviridae and Comoviridae, the unassigned genera Cheravirus and Sadwavirus, and the proposed genus Torradovirus
Taxonomy of the family Arenaviridae and the order Bunyavirales: update 2018
In 2018, the family Arenaviridae was expanded by inclusion of 1 new genus and 5 novel species. At the same time, the
recently established order Bunyavirales was expanded by 3 species. This article presents the updated taxonomy of the family
Arenaviridae and the order Bunyavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV)
and summarizes additional taxonomic proposals that may affect the order in the near future
Detection by high-throughput sequencing and molecular characterization of complexes of fabaviruses infecting ‘Staccato (R)
- …