The complete genome sequence of Plodia interpunctella granulovirus: Discovery of an unusual inhibitor-of-apoptosis gene

Authors: Harrison, Robert - Bob; Rowley, Daniel; FUNK, C.JOEL - John Brown University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2016
Publication Date: 10/1/2016
Citation: Harrison, R.L., Rowley, D.L., Funk, C. 2016. The complete genome sequence of Plodia interpunctella granulovirus: Discovery of an unusual inhibitor-of-apoptosis gene. PLoS One. 11(7):e0160389.

Interpretive Summary: The Indianmeal moth is a worldwide pest of stored grains, nuts, and other foodstuffs. A virus that infects and kills larvae of the moth had previously been discovered and developed into a environmentally safe product for suppressing Indianmeal moth infestations. To obtain a more complete understanding of the genetic factors regulating the insecticidal activity of the Indianmeal moth virus, its entire genomic DNA sequence was determined and analyzed. Features of the genome that may contribute to this virus’s insecticidal activity were documented, and along with its relationships to other similar insect viruses. The information in this study contributes to progress towards improving Indianmeal moth virus-based insecticides, and will be of interest to those in academia, government, and industry who work with this group of insect viruses or with Indianmeal moth and its management.

Technical Abstract: The Indianmeal moth, Plodia interpunctella (Lepidoptera: Pyralidae), is a common pest of stored goods with a worldwide distribution. The complete genome sequence for a larval pathogen of this moth, the baculovirus Plodia interpunctella granulovirus (PiGV), was determined by next-generation sequencing. The PiGV genome was found to be 112, 536 bp in length with a 44.2% G+C nucleotide distribution. A total of 123 open reading frames (ORFs) and seven homologous regions (hrs) were identified and annotated. Phylogenetic inference using concatenated alignments of 37 baculovirus core genes placed PiGV in the “b” clade of viruses from genus Betabaculovirus with a branch length suggesting that PiGV represents a previously undescribed betabaculovirus species. In addition to the baculovirus core genes and orthologues of other genes found in other betabaculovirus genomes, the PiGV genome sequence contained orthologues of the bidensovirus NS3 gene, as well as ORFs that occur in alphabaculoviruses but not betabaculoviruses. While PiGV contained an orthologue of inhibitor of apoptosis-5 (iap-5), an orthologue of inhibitor of apoptosis-3 (iap-3) was not present. Instead, the PiGV sequence contained an ORF (PiGV ORF81) encoding an IAP homologue with sequence similarity to insect cellular IAPs, but not to viral IAPs. Phylogenetic analysis of baculovirus and insect IAP amino acid sequences suggested that the baculovirus IAP-3 genes and the PiGV ORF81 IAP homologue represent different lineages arising from more than one acquisition event. The presence of genes from other sources in the PiGV genome highlights the extent to which baculovirus gene content is shaped by horizontal gene transfer.