Genomic Characterization of a Novel Virus of the Family Tymoviridae Isolated from Mosquitoes

Abstract

BackgroundThe family Tymoviridae comprises three plant virus genera, including Tymovirus, Marafivirus, and Maculavirus, which are found in most parts of the world and cause severe agricultural losses. We describe a putatively novel member of the family Tymoviridae, which is isolated from mosquitoes (Culex spp.), referred to as CuTLV.Methods and ResultsThe CuTLV was isolated by cell culture, which replicates and causes cytopathic effects in Aedes albopictus C6/36 cells, but not in mammalian BHK-21 or Vero cells. The complete 6471 nucleotide sequence of CuTLV was determined. The genome of CuTLV is predicted to contain three open reading frames (ORFs). The largest ORF1 is 5307 nucleotides (nt) in length and encodes a putative polypeptide of 1769 amino acids (aa), which contains the conserved motifs for the methyltransferase (MTR), Tymovirus endopeptidase (PRO), helicase (HEL), and RNA-dependent RNA polymerase (RdRp) of the replication-associated proteins (RPs) of positive-stranded RNA viruses. In contrast, the ORF1 sequence does not contain the so-called “tymobox” or “marafibox”, the conserved subgenomic RNA promoter present in all tymoviruses or marafiviruses, respectively. ORF2 and ORF3 putatively encode a 248-aa coat protein (CP) and a proline-rich 149-aa polypeptide. The whole genomic nucleotide identity of CuTLV with other members of family Tymoviridae ranged from 46.2% (ChiYMV) to 52.4% (GFkV). Phylogenetic analysis based on the putative RP and CP genes of CuTLV demonstrated that the virus is most closely related to viruses in the genus Maculavirus.ConclusionsThe CuTLV is a novel virus related to members of the family Tymoviridae, with molecular characters that are distinct from those of tymoviruses, marafiviruses, and other maculaviruses or macula-like viruses. This is the first report of the isolation of a Tymoviridae-like virus from mosquitoes. Further investigations are required to clarify the origin, replication strategy, and the public health or agricultural importance of the CuTLV.

Viromics on Honey-Baited FTA Cards as a New Tool for the Detection of Circulating Viruses in Mosquitoes

“…Moreover, a Culex Tymoviridae-like virus (CuTLV) that was isolated from a Culex spp. pool from Xinjiang (China) was also shown to produce a cytopathic effect on Aedes albopictus C6/36 cell line [55], suggesting a potential plant/mosquito host-shift even when there is no record of mosquitoes as vectors of plant viruses [46]. Nonetheless, there is also the chance that: i) mosquitoes could have acquired these viruses while sap or nectar feeding prior to capture and deposited them on the FTA card along with saliva expectorations as mouthparts contaminants [49,56] while trapped; or ii) they could have been present in the honey used as bait.…”

Isolation and Identification of a Natural Reassortant Mammalian Orthoreovirus from Least Horseshoe Bat in China

“…Whole genome sequences of 10 segments (L1–L3, M1–M3, S1–S4) of the isolate were determined by DNase-sequence-independent single primer amplification (DNase-SISPA) and the rapid amplification of cDNA ends (RACE) methods as described previously [ 15 ]. The genome sequences of all segments were reconfirmed by overlapping nested PCRs with specific primers ( Table 1 ) derived from the completed viral genomes.…”

Identification and characterisation of common glow-worm RNA viruses

“…Tymoviridae are positive-strand RNA viruses without an envelope. Tymoviruses infect mainly plants but they have also been found in insects, such as, bees (NCBI txid:1,682,186) [24,25], silkworms (288,456 and 2,065,033) [26], mites (1,682,187 and 1,005,993) [25], and mosquitoes (1,236,047) [27].…”