Michael R. Strand
from: Insect Virology (Edited by: Sassan Asgari and Karyn N. Johnson). Caister Academic Press, U.K. (2010)
Viruses in the family Polydnaviridae are symbiotically associated with parasitoid wasps in the families Braconidae and Ichneumonidae. Polydnaviruses (PDVs) exist in two forms. In wasps, they persist and are transmitted to offspring as stably integrated proviruses. Replication is restricted to specialized cells in the ovaries of females. This results in production of the encapsidated form of the virus, which wasps inject into hosts when they oviposit. PDVs do not replicate in the wasp's host but they do infect different tissues and express gene products that facilitate successful development of the wasp's offspring. In this chapter, I first discuss the phylogenetic distribution of PDVs in wasps and key features that distinguish the encapsidated form of these viruses. I then review current understanding of how the proviral form of PDVs is organized in the genome of wasps, how PDVs replicate, and the origins of this virus family. I end the chapter with a discussion of the gene products PDVs produce and the role they play in parasitism read more ...