ICTV Virus Taxonomy Profile: Rhabdoviridae 2022

1Virions are usually enveloped and bullet-shaped or bacilliform (i.e. with two rounded ends) and contain five structural proteins (Table 1, Fig. 1). The nucleocapsid protein (N), the large multi-functional RNA-directed RNA polymerase (L) and the polymerase-associated phosphoprotein (P), together with the RNA genome, form the ribonucleoprotein (RNP) complex. The nucleocapsid is encased in the matrix protein (M) layer, which also interacts with the envelope containing the transmembrane glycoprotein (G). Rhabdoviruses assigned to the genera Dichorhavirus and Varicosavirus lack an envelope.

2Rhabdovirus negative sense (−) RNA genomes are 10–16 kb (Fig. 2). Almost all rhabdovirus genomes are unsegmented, but rhabdoviruses with bi-segmented genomes are also known. Terminal non-coding regions are partially complementary. Genomes usually encode five major structural proteins but may also encode additional (accessory) proteins, either in additional genes or as alternative ORFs within the structural protein genes.

3Rhabdovirus replication generally occurs in the cytoplasm following receptor-mediated endocytosis. Primary transcription is initiated from the incoming (−)RNP complex by the RNA-directed RNA polymerase (RdRP). Stop–start transcription occurs 3′ to 5′ using gene start and gene end sequences to generate polyadenylated mRNAs. Replication is initiated by the RdRP from a single promoter at the 3′-end, ignoring gene start and gene end sequences to generate a (+)RNP. This is the template for nascent (−)RNPs, which are assembled with M and G into enveloped virions. Budding can occur at either the plasma membrane or internal membranes. Some plant rhabdoviruses replicate in the nucleus.

4Current taxonomy: ictv.global/taxonomy. Viruses assigned to each genus form a monophyletic clade based on phylogenetic analyses of L protein sequences and usually have similar genome organizations, including the number and locations of accessory genes. Rhabdoviruses have been isolated from a wide range of vertebrates and plants; many have been isolated from arthropods. The subfamily Alpharhabdovirinae includes >30 genera for viruses infecting only vertebrates, only invertebrates, or vertebrate hosts and arthropod vectors. These viruses have been referred to informally as dimarhabdoviruses (dipteran and mammalian rhabdoviruses), but various members may infect birds, reptiles, amphibians, non-dipteran insects, ticks, or nematodes. The subfamily Betarhabdovirinae includes >five genera for viruses infecting plant hosts and arthropod vectors. These include viruses with bi-segmented genomes (genera Dichorhavirus and Varicosavirus) and rod-shaped, non-enveloped virions (genus Varicosavirus). The subfamily Gammarhabdovirinae includes the genus Novirhabdovirus for viruses infecting teleost fish. Several other genera are not assigned to a subfamily; viruses assigned to these genera have been detected by high-throughput sequencing of invertebrate metagenomes.

5Full ICTV Report on the family Rhabdoviridae: ictv.global/report/rhabdoviridae.