Subfamily: Deltarhabdovirinae

Genus: Alphahymrhavirus

Distinguishing features

Viruses assigned to the genus Alphahymrhavirus form a distinct monophyletic group based on well-supported Maximum Likelihood or Maximum Clade Credibility trees inferred from complete L sequences. Members of the genus have been detected in hymenopteran insects (Hymenoptera) including wasps and ants. They are distant phylogenetically from viruses assigned to the genera Betahymrhavirus and Gammahymrhavirus.

Virion

Morphology

Viruses assigned to the genus have not yet been visualized by electron microscopy.

Nucleic acid

Alphahymrhavirus genomes consist of a single molecule of negative-sense, single-stranded RNA of approximately 11.6–12.4 kb (Käfer et al., 2019, Kleanthous et al., 2019, Wang et al., 2021).

Proteins

Alphahymrhavirus N, P, M, G and L proteins share sequence homology and/or structural characteristics with the cognate proteins of other rhabdoviruses. Alphahymrhavirus G proteins are class I transmembrane glycoproteins. Alignment with the G protein of vesicular stomatitis Indiana virus indicates likely conservation of only 6 of the 12 conserved cysteine residues that are typical of animal rhabdovirus G proteins (Walker and Kongsuwan 1999, Roche et al., 2006).

Genome organisation and replication

Alphahymrhavirus genomes include the five genes (N, P, M, G and L) encoding the structural proteins (Figure 1 Alphahymrhavirus).

Figure 1 Alphahymrhavirus. Schematic representation of alphahymrhavirus genomes shown in reverse (positive-sense) polarity. The five long open reading frames (ORFs) in the N, P, M, G and L genes are shown (open arrows). In hymenopteran rhabdo-related virus 109, an alternative ORF commences near the start of the P gene (pink) but it is not known if it is expressed.

Biology

Lasius neglectus virus 2 (species Alphahymrhavirus neglectus) was discovered in the transcriptome of invasive garden ants (Lasius neglectus) collected in the United Kingdom (Kleanthous et al., 2019). Hymenopteran rhabdo-related virus 38 (species Alphahymrhavirus cinereus) was discovered in the transcriptome shotgun assembly (TSA) of a leaden spider wasp (Pompilus cinereus) collected in Germany (Käfer et al., 2019). Hymenopteran rhabdo-related virus 46 (species Alphahymrhavirus radians) was discovered in the transciptome shotgun assembly of a leaden cuckoo wasp (Chrysura radians) collected in Turlin, Italy (Käfer et al., 2019). Hymenopteran rhabdo-related virus 109 (species Alphahymrhavirus hirtum) was discovered in the TSA of leaden cricket-hunting wasps (Chlorion hirtum) collected in Israel (Käfer et al., 2019). Lariophagus distinguendus negative strand RNA virus 1 (species Alphahymrhavirus distinguendus) was detected by metagenomic sequencing of endoparasitoid wasps (Lariophagus distinguendus) of rice weevil (Sitophilus oryzae) larvae and pupae collected in China (Wang et al., 2021). Xiangshan rhabdo-like virus 3 (species Alphahymrhavirus xiangshan) was detected by metagenomic sequencing of a mixed sample of insects (Hymenoptera, Diptera, Lepidoptera) collected in Beijing, China. No isolates are currently available for any of these viruses.

Species demarcation criteria

Viruses assigned to different species within the genus have several of the following characteristics: A) minimum amino acid sequence divergence of 10% in N proteins; B) minimum amino acid sequence divergence of 10% in the L proteins; C) minimum amino acid sequence divergence of 15% in G proteins; D) significant differences in genome organisation as evidenced by numbers and locations of ORFs; E) can be distinguished in virus neutralisation tests; and F) occupy different ecological niches as evidenced by differences in invertebrate hosts.

Related, unclassified viruses

Virus names and virus abbreviations are not official ICTV designations.

* Coding region sequence incomplete