Family: Phenuiviridae

Genus: Goukovirus

Distinguishing features

Eleven viruses are assigned to the genus Goukovirus. Goukoviruses have been identified in arthropods, including aphids, cockroaches, mosquitoes, and termites. The goukovirus genome has four genes, encoding a large protein (L), two external glycoproteins (Gn and Gc), and a nucleocapsid protein (N). Based on well-supported Maximum Likelihood or Maximum Clade Credibility trees inferred from complete L protein sequences, viruses classified in the genus Goukovirus form a monophyletic cluster clearly distinguished from other phenuivirids. (Marklewitz et al., 2011, Auguste et al., 2014, Li et al., 2015).

Virion

Morphology

Virions are spherical or pleomorphic, 40–60 nm in diameter, and have surface glycoprotein projections of 5–10 nm which are embedded in a lipid bilayer envelope approximately 5 nm thick (Marklewitz et al., 2011, Auguste et al., 2014).

Nucleic acid

The goukovirus genome encompasses three segments of negative-sense RNA. The terminal nucleotides of each segment occur in a canonical, conserved sequence (in coding sense) 5′-ACACAGUGAC…GACUUUGUGU-3′ and may form panhandle structures similar to those of other members of the class Bunyaviricetes. The L segment (6.3–6.8 kb) encodes a protein with a predicted molecular mass of 228.2–249.6 kD that includes a region that shares homology with the bunyaviral RNA-directed RNA polymerase (RdRP) domain. The M segment (3.2–3.3 kb) encodes a protein of 105.8–113.0 kDa that shares homology with phlebovirus glycoprotein G1 and G2 sequences, and also to the phlebovirus glycoprotein C-terminal Ig-like domain. The S segment (1.0–1.2 kb) encodes a protein of 28.1–32.0 kDa that shares homology with the tenuivirus/phlebovirus N domain.

Genome organization and replication

The goukovirus genome consists of three negative-sense RNAs (Figure 1 Goukovirus). The goukovirus genome arrangement is similar to that of beidiviruses, citriciviruses, hudiviruses, hudoviruses, mobuviruses, phasiviruses, pidchoviruses, and tanzaviruses (Figure 2 Phenuivridae). All three genomic RNAs contain untranslated regions flanking a single ORF which, based on comparisons with other negative-sense RNA viruses, is predicted to be contained in the virus complementary strand. The L, M, and S segments putatively encode L, a glycoprotein precursor comprising Gn and Gc, and N, respectively. The Gn and Gc glycoproteins, respectively, were earlier referred to as G1 and G2 based on their apparent size following gel electrophoresis. The goukovirus genome does not encode either of the non-structural proteins NSm or NSs. Details of virus replication are unknown (Marklewitz et al., 2011, Auguste et al., 2014).

Figure 1 Goukovirus. Genome organization of a goukovirus. Coloured boxes depict ORFs that encode N, nucleocapsid protein; Gn and Gc, external glycoproteins; and L, large protein.

Biology

Goukoviruses have been found in aphid Aulacorthum magnoliae (Essig & Kuwana, 1918), cockroach Blattella germanica (Linnaeus, 1767), jumping plant lice Aphalara polygoni (Foerster, 1848), mosquitoes Culex decens (Theobald, 1901) and Culex portesi (Senevet & Abonnenc, 1941), and termites Hodotermopsis sjostedti Holmgren, 1911 and Reticulitermes chinensis Snyder, 1923. Cumuto virus and Gouleako virus were isolated from mosquitoes, and it has been confirmed that the viruses replicate in insects but not in vertebrate cells (Marklewitz et al., 2011, Auguste et al., 2014, Li et al., 2015).

Species demarcation criteria

The criteria demarcating species in the genus are:

•　Less than 95% identity in the amino acid sequence of the L protein.

Related, unclassified viruses

* Sequences do not comprise the complete genome segment.

Virus names and virus abbreviations are not official ICTV designations.