Notes on Genus: Begomovirus alphasatellites
no particles of their own
Type member:
Contents
General Description
Alphasatellites were first discovered in association with begomoviruses (where they were initially described as DNA-1 molecules). They encode a rolling-circle replication initiator protein (Rep) and are capable of self-replication in an appropriate host but depend upon the helper virus for encapsidation and movement between plants. Unlike the
Begomovirus betasatellites, they have no effect on symptoms and appear to have no role in the disease process. The sequences are related to the Rep proteins of nanoviruses, the genomes of which often have additional satellite like DNAs that form a separate group of
Nanoviridae alphasatellites.
Morphology
There are no distinctive virions because they are encapsidated in the coat protein of their helper virus.
Genome
Monopartite, circular, ssDNA of 1300-1400nt.
Genus Genomic Organization
The DNA encodes a single protein of 34-37 kDa in the virion (positive) sense that has similarity to the replication-associated protein of members of the family
Nanoviridae and the
Nanoviridae alphasatellites. They are not officially classified by ICTV, but are here organised into "species-like" clusters within which the sequences are closely related (usually >80% nt identity) to one another.
Type Member Genomic Organization
There is no formal type member.
