Family: Phenuiviridae

Genus: Beidivirus

Distinguishing features

Húběi diptera virus 3 (HbDV3) is assigned to Beidivirus muscae, the only species in the genus. Beidivirus RNA has been detected by high-throughput sequencing of RNA from a pool of flies (Diptera spp.) from Húběi (湖北省), China. The beidivirus 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 Beidivirus form a monophyletic cluster clearly distinguished from other phenuivirids. There currently is no cultured beidivirus isolate (Shi et al., 2016).

Virion

Morphology

Virion morphology is unknown. Based on the putative proteins encoded by the virus genome, the virion is probably a spherical or pleomorphic virion with an enveloped structure.

Nucleic acid and Protein

The beidivirus genome encompasses three segments of negative-sense RNA: L (6.5 kb), M (3.8 kb), and S (1.3 kb). Analysis of the terminal sequences has yet to be completed. 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 beidivirus putative ORF sequences suggests that the beidivirus genome encodes three structural proteins: L with a predicted molecular mass of 250 kDa, a glycoprotein precursor (GP) of 135 kDa, and N of 33 kDa. These proteins share sequence homology and/or structural characteristics with the cognate proteins of other phenuivirids (Table 3.Phenuiviridae) (Shi et al., 2016).

Genome organization and replication

Beidivirus genome arrangement is similar to that of citriciviruses, goukoviruses, hudiviruses, hudoviruses, phasiviruses, pidchoviruses, and tanzaviruses (Figure 1.Beidivirus). The L, M and S segments putatively encode L, a glycoprotein precursor (comprising Gn and Gc) and N, respectively. The Gn and Gc glycoproteins of 79 kDa and 56 kDa were earlier referred to as G1 and G2 based on apparent size on gel electrophoresis. The beidivirus genome does not encode either of the non-structural proteins NSm or NSs. Details of virus replication are unknown (Shi et al., 2016).

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

Biology

The only known virus was detected in a pool of flies (Diptera spp.).

Species demarcation criteria

Not defined as the genus currently includes only a single species.