Bidensovirus

Bidensovirus
Virus classification
(unranked):	Virus
Realm:	Monodnaviria
Kingdom:	Shotokuvirae
Phylum:	Cossaviricota
Class:	Mouviricetes
Order:	Polivirales
Family:	Bidnaviridae
Genus:	Bidensovirus
Species
Bombyx mori bidensovirus

Bidensovirus is a genus of single stranded DNA viruses that infect invertebrates. The species in this genus were originally classified in the family Parvoviridae (subfamily Densovirinae) but were moved to a new genus because of significant differences in the genomes.^[1]

Taxonomy

There is one species in this genus currently recognised: Bombyx mori bidensovirus.

Host

As the name suggests this virus infects Bombyx mori, the silkworm.^[2]

Virology

The virions are

The genome is bipartite, unique among ssDNA viruses, with two linear segments of ~6 and 6.5 kilobases (kb). These segments and the complementary strands are that are packaged separately giving rise to 4 different types of full particles.

Both segments have an ambisense organization, coding for a structural protein in one sense and the non-structural proteins on the complementary strand.

• DNA1 (also known as VD1) — the larger segment of 6.5 kb — encodes the capsid protein VP1 (128 kDa — kilodaltons) on one strand and three non-structural proteins — NS1 of 14 kDa, NS2 of 37 kDa and NS3 of 55 kDa — on the complementary strand.

• DNA2 (also known as VD2) — the smaller segment of 6 kb — encodes the capsid protein VP2 (133 kDa) on one strand and the non-structural protein NS4 (27 kDa) on the complementary strand.

The open reading frame 4 (VD1-ORF4) is 3318 nucleotides (bases) in length and encodes a predicted (3318/3 − 1 =) 1105 amino acid protein which has a conserved DNA polymerase motif. It appears to encode at least 2 other proteins including one of ~53 kDa that forms part of the virion.^[3]

Evolution

Comprehensive analysis of bidnavirus genes has shown that these viruses have evolved from a