Mixtures of Insect-Pathogenic Viruses in a Single Virion: towards the Development of Custom-Designed Insecticides

Area of Science:

• Virology
• Insect Pathology
• Biotechnology

Background:

• Alphabaculoviruses (Baculoviridae) are DNA viruses pathogenic to Lepidoptera.
• They are utilized as biological insecticides and expression vectors.
• Baculoviruses possess a structure facilitating genome group transmission.

Purpose of the Study:

• To investigate the consequences of coinfection with multiple alphabaculovirus species in insects.
• To determine if mixed-virus occlusion bodies are produced and transmitted.
• To assess the persistence and implications of mixed-virus populations.

Main Methods:

• Coinfection of susceptible insects with different alphabaculovirus species.
• Analysis of occlusion bodies for the presence of multiple viruses.
• Endpoint dilution assays to confirm coinfection and replication within single cells.
• Evaluation of viral nucleocapsid length in mixed infections.

Main Results:

• Coinfection led to mixed-virus occlusion bodies containing parental viruses, irrespective of phylogenetic distance.
• Approximately half of the virions in occlusion bodies contained both viruses, indicating co-replication and co-envelopment.
• Mixed-virus populations persisted through multiple rounds of insect-to-insect transmission.
• Coinfection with viruses of differing genome sizes altered viral nucleocapsid length.

Conclusions:

• Alphabaculovirus coinfection can result in the co-envelopment of multiple viral genomes within single virions.
• Mixed-virus populations are stable and transmissible across generations.
• This phenomenon has significant implications for developing novel, multi-target biological insecticides.