Biology of Satellites

"Satellites are subviral agents incapable of autonomous replication, which are dependent on the presence of a helper virus for their multiplication, but are generally dispensable for the helper infection cycle. Satellites share the requirement for virus-encoded replication proteins with defective interfering (DI) RNAs, but differ from these in sequence composition: DI RNAs are entirely derived from the helper virus genome, whereas satellites share little or no significant sequence similarity with the helper genom. This chapter will focus on some biological features of plant satellite viruses and nucleic acids."