Group Group IV ((+)ssRNA) Rank Family | Order Unassigned | |
Similar Chrysovirus, Partitiviridae, Tetraviridae, Leviviridae, Totiviridae | ||
Narnaviridae is a family of positive single stranded RNA viruses. Members of this family have no capsid. Fungi serve as natural hosts. There are currently seven species in this family, divided among 2 genera.
Contents
Virology
The genome of these viruses is unipartate and between 2.3 and 3.5 kilobases in length. It encodes a single gene—the RNA dependent RNA polymerase. This protein is associated with the genome in the cytoplasm of the host. The viruses do not have a capsid or envelop and do not form any infectious viral particles except lipid vesicles.
They infect fungi (including yeast) and oomycetes. Mitovirues appear to be among the most common fungi viruses.
Life Cycle
Viral replication is cytoplasmic. Replication follows the positive stranded RNA virus replication model. Positive-stranded RNA-virus transcription is the method of transcription. The virus exits the host cell by cell to cell movement. Fungi serve as the natural host. Transmission routes are parental and sexual.
Taxonomy
Two genera have been recognised to date. Mitoviruses infect the mitochondria of fungi while narnaviruses remain within the cytoplasm of the host cell.
Group: ssRNA(+)
Other proposed members of the Mitovirus genus are OnuMV1c and OnuMV7.
Their closest relatives among RNA viruses are plant-infecting viruses of genus Ourmiavirus, which, however, have a capsid and a number of other proteins. Other close relatives are bacteriophages of the family Leviviridae.