Family: Phenuiviridae

Genus: Hudovirus

Distinguishing features

Three viruses are assigned to the genus Hudovirus. Hudovirus RNA was found by high-throughput sequencing of RNA from butterflies, mosquitoes, and pink bollworms. The hudovirus genome has three genes, encoding a large protein (L), a glycoprotein precursor (GP), 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 Hudovirus form a monophyletic cluster clearly distinguished from other phenuivirids (Shi et al., 2016, Dou et al., 2021, Orba et al., 2023).

Virion

Morphology

Virion morphology is unknown.

Nucleic acid

The hudovirus genome encompasses three segments of negative-sense RNA, namely L (7.5–7.9 kb), M (5.0–5.4 kb) and S (1.3–2.4 kb). The terminal nucleotides of each segment occur in a canonical, conserved sequence (in coding sense) 5′-ACACAAAGAC… GUCUUUGUGU-3′ and may form panhandle structures typical of other members of the class Bunyaviricetes. 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. In silico analysis of hudovirus putative ORF sequences suggests that the hudovirus genome encodes three structural proteins: L with a predicted molecular mass of 275.4–290.4 kDa, a glycoprotein precursor of 162.6–176.8 kDa and N of 31.1–31.5 kDa, all of which share sequence homology and/or structural characteristics with the cognate proteins of other phenuivirids (Shi et al., 2016).

Genome organization and replication

The hudovirus genome consists of three negative-sense RNAs (Figure 1 Hudovirus). The hudovirus genome arrangement is similar to that of beidiviruses, citriciviruses, goukoviruses, hudiviruses, mobuviruses, phasiviruses, pidchoviruses, and tanzaviruses (Figure 2 Phenuivridae). The L, M and S segments putatively encode L, a glycoprotein precursor and N, respectively. While the hudovirus GP harbors the phlebovirus glycoprotein G2 fusion domain, the GP lacks the phlebovirus glycoprotein G1 and the C-terminal Ig-like domains, its potential functional congruence with GPs of other bunyavirals remains to be elucidated. The hudovirus genome does not encode the non-structural proteins NSs or NSm. Details of virus replication are unknown (Shi et al., 2016).

Figure 1 Hudovirus. Genome organization of a hudovirus. Coloured boxes depict ORFs that encode N, nucleocapsid protein; GP, glycoprotein precursor; and L, large protein.

Biology

Hudoviruses have been detected in pools of butterflies (unidentified Lepidoptera) sampled in Húběi (湖北省), China and mosquitoes (Culex quinquefasciatus Say, 1823) sampled in Mongu, Zambia. Hudovirus RNA was also discovered in SRA data of pink bollworms (Pectinophora gossypiella (Saunders, 1844)) (Shi et al., 2016).

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

Virus names and virus abbreviations are not official ICTV designations.