Identification, characterization and phylogenic analysis of conserved genes within the odvp-6e/odv-e56 gene region of Choristoneura fumiferana granulovirus.

Abstract

The genes that are located within the odvp-6e/odv-e56 region of the Choristoneura fumiferana granulovirus (ChfuGV) were identified by sequencing the 11 kb BamHI restriction fragment on the ChfuGV genome. The global GC content that was calculated from the data obtained from this genomic region was 34.96%. The open-reading frames (ORFs), located within the odvp-6e/odv-e56 region, are presented and compared to the equivalent ORFs that are located at the same region in other GVs. This region is composed of 14 ORFs, including three ORFs that are unique to ChfuGV with no obvious homologues in other baculoviruses as well as eleven ORFs with homologues to granuloviral ORFs, such as granulin, CfORF2, pk-1, ie-1, odv-e18, p49, and odvp-6e/odv-e56. In this study, the conceptual products of seven major conserved ORFs (granulin, CfORF2, IE-1, ODV-E18, p49 and ODVP-6E/ODV-E56) were used in order to construct phylogenetic trees. Our results show that granuloviruses can be grouped in 2 distinct groups as follows: Group I; Choristoneura fumiferana granulovirus (ChfuGV), Cydia pomonella granulovirus (CpGV), Phthorimaea operculella granulovirus (PhopGV), and Adoxophyes orana granulovirus (AoGV). Group II; Xestia c-nigrum granulovirus (XcGV), Plutella xylostella granulovirus (PxGV), and Trichoplusia ni granulovirus (TnGV). The ChfuGV conserved proteins are most closely related to those of CpGV, PhopGV, and AoGV. Comparative studies, performed on gene arrangements within this region of genomes, demonstrated that three GVs from group I maintain similar gene arrangements.