alphabaculovirus

Alphabaculovirus is a genus of the family Baculoviridae, within the subfamily Alphabaculovirinae, comprising nucleopolyhedroviruses (NPVs) that infect lepidopteran larvae. Members produce occlusion bodies and replicate in the nucleus of infected cells.

Genomes are circular double-stranded DNA, typically 80,000 to 180,000 base pairs in length, encoding roughly 90 to 180 open reading frames. The majority of genes are conserved across baculoviruses, with a set of core genes shared among alphabaculoviruses. The major occlusion body protein is polyhedrin.

The viral life cycle includes two infectious forms: occlusion-derived virus (ODV) within occlusion bodies for oral infection of larvae and budded virus (BV) for systemic infection. After ingestion of occlusion bodies, the virus dissolves in the gut, initiates infection, and later produces OBs again in infected tissues.

Ecology and applications: Alphabaculoviruses are usually host-specific to Lepidoptera. They are used as biological control agents against pest insects and as tools in molecular biology for gene expression and insect-control strategies. Well-known examples include Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Helicoverpa armigera nucleopolyhedrovirus (HearNPV).

Taxonomy: Alphabaculovirus comprises NPVs; it is contrasted with Betabaculovirus, which includes granuloviruses (GVs). Both groups form occlusion bodies and replicate similarly but differ in occlusion body structure and host range.