Measuring the Mamestra configurata Nucleopolyhedrosis Virus Transcriptome: Personalized Insect Genomics

We are investigating transcription by a baculovirus during infection of its host, the Bertha armyworm, Mamestra configurata, a significant pest of canola production in Western Canada. Knowledge of gene expression by the virus and host will be crucial to understanding how the two interact at the molecular level, and necessary to ultimately tap the potential of these viruses as biopesticides.
Previously, the cascade of gene expression that occurs during infection by baculoviruses has traditionally been measured in insect cells cultured and infected in vitro. This system provides robust information on transcription but is not fully representative of the in vivo environment in the larval midgut where the initiation of infection naturally occurs. Characterizing viral gene expression in the insect is difficult due to the low levels of virus transcripts at early time points relative to a very high background of host gene expression. To achieve this we have previously used both RNA sequencing and digital PCR approaches, which have revealed a specific suite of open reading frames (ORFs) that are detected in the initial phase of infection.
Recent studies exploring viral transcription using individual insects has, however, uncovered additional complexities to this story, and the potential implications of this personalized genomic approach will be discussed.