Partitiviridae

Partitiviridae are plant and fungi group III viruses with double stranded RNA genomes. Their name comes from the Latin partitius which means divided and they are called this as they have segmented genomes. There are three genera within the Partitiviridae family:

• Partitivirus example Atkinsonella hypoxylon virus (AhV)
• Alphacryptovirus example White Clover Cryptic Virus 1 (WCCV-1)
• Betacryptovirus example White Clover Cryptic Virus 2 (WCCV-2)

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Partitiviruses mainly infect fungi whereas Alphacryptoviruses and Betacryptoviruses infect plants. The viruses are quite specific when it comes to their host and in plants they are generally transmitted by seeds. Fungal Partitiviruses are generally only transmitted vertically or be hyphal anastomosis. Until recently there was thought to be a fourth genus in this family, the Chrysovirus which infect fungi such as penicillium but they have formed their own family called Chrysoviridae which include the Penicillium chrysogenum virus.

Genome and Structure

Partitiviruses have double stranded RNA genomes divided into two genomic segments and there may be additional subgenomic segments. The genome segments are packaged in the same virus particle, the larger segment codes for the RNA-dependent RNA polymerase and the smaller codes for the coat protein. The total length of the genome is 3000-10000 nucleotides in length. The virus particle is non-enveloped and icosahedral with a diameter between 30-35nm.

References

• ICTVdB