Family: Phasmaviridae

Genus: Jonvirus

Distinguishing features

The only classified jonvirus is jonchet virus (JONV). JONV is associated with dipteran insects (Marklewitz et al., 2015).

Virion

Jonviruses produce virions in two distinctive virion morphologies, spherical/pleomorphic and tubular (60 nm × up to 600 nm) (Marklewitz et al., 2015) (Figure 1 Jonvirus).

Figure 1 Jonvirus. Electron micrograph of negative-stained virions of jonchet virus sedimented by ultracentrifugation. Scale bar: 100 nm (image reproduced from 26038576).

Nucleic acid

Jonviruses have tri-segmented negative-sense RNA genomes of about 12.7–14.1 kb (small [S] segment: 1.7–1.8 kb; medium [M] segment: 5.4 kb; large [L] segment: 6.8–6.9 kb (Marklewitz et al., 2015).

Proteins

Jonviruses express three structural proteins: nucleoprotein (N), glycoprotein precursor (GPC), and large protein (L), as well as one nonstructural protein (NSs) (Marklewitz et al., 2015).

Carbohydrates

The G_N and G_C envelope proteins, derived from GPC by proteolysis, are predicted to be glycosylated, and these proteins are sensitive to N-glycosidase treatment (Marklewitz et al., 2015).

Genome organization and replication

The S segment encodes N and NSs, the M segment encodes GPC, and the L segment encodes L protein (Marklewitz et al., 2015) (Figure 2 Jonvirus). Jonvirus genomic segments are expected, by analogy with other bunyaviricetes, to assume circular ribonucleoprotein complexes within the virion via non-covalent binding of complementary and conserved 3′- and 5′-terminal sequences. Complementary terminal sequences for the three segments of JONV are 5′-AGUAGUA (Marklewitz et al., 2015). During replication of JONV in C6/36 mosquito cell culture, viral RNA and mRNA were shown to be similar in length, and mRNAs included 6–23 5′ non-viral nucleotides obtained by cap-snatching. JONV replication was blocked in vertebrate cells and at temperatures above 32°C, indicating an insect-only transmission cycle (Marklewitz et al., 2015).

Figure 2 Jonvirus. Schematic representation of jonvirus genome organization. L: gene encoding L protein; GPC, gene encoding GPC; N: gene encoding N protein; NSs: gene encoding NSs.

Biology

Classified and putative jonviruses are associated with culicid mosquitoes (Culex spp.) in Côte d’Ivoire (Marklewitz et al., 2015, Hermanns et al., 2023).

Species demarcation criteria

Not applicable as the genus includes only a single species.

Related, unclassified viruses

Virus names and virus abbreviations are not official ICTV designations.