The Genome Sequence and Evolution of Baculoviruses

Abstract

Comparative analysis of the complete genome sequences of 13 baculoviruses revealed a core set of 30 genes, 20 of which have known functions. Phylogenetic analyses of these 30 genes yielded a tree with 4 major groups: the genus Granulovirus (GVs), the group I and II lepidopteran nucleopolyhedroviruses (NPVs), and the dipteran NPV, CuniNPV. These major divisions within the family Baculoviridae were also supported by phylogenies based on gene content and gene order. Gene content mapping has revealed the patterns of gene acquisitions and losses that have taken place during baculovirus evolution, and it has highlighted the fluid nature of baculovirus genomes. The identification of shared protein phylogenetic profiles provided evidence for two putative DNA repair systems and for viral proteins specific for infection of lymantrid hosts. Examination of gene order conservation revealed a core gene cluster of four genes, helicase, lef-5, ac96, and 38K(ac98), whose relative positions are conserved in all baculovirus genomes.

Genomic and host range studies of Maruca vitrata nucleopolyhedrovirus

“…Two transcriptionspecific genes lef-10 and lef-12, previously identified in AcMNPV and BmNPV, were also present in MaviNPV as ORFs 39 and 30, respectively. In addition, MaviNPV encodes homologues of 39K (ORF25), lef-6 (ORF19) and lef-11 (ORF26), which are present in all sequenced lepidopteran baculoviruses (Herniou et al, 2003). Although AcMNPV, BmNPV and MaviNPV are all closely related, we note that while the amino acid identity of AcMNPV lef-6 and BmNPV lef-6 aa is 93 %, the identity between MaviNPV lef-6 aa and AcMNPV or BmNPV is only 34-35 %.…”

“…All 126 MaviNPV ORFs have an assigned function or homologues in other baculoviruses. The 29 genes shared by all baculovirus genomes, including the dipteran and hymenopteran baculoviruses (Herniou et al, 2003;Garcia-Maruniak et al, 2004), were also found in the MaviNPV genome. The 126 predicted ORFs are encoded by 92 % of the MaviNPV genome; the rest is made up of intergenic spaces and hrs.…”

“…A phylogenetic tree was inferred from a dataset of combined amino acid sequences of the 29 baculovirus core genes (Herniou et al, 2003;Jehle et al, 2006) of the 33 baculoviruses that had been completely sequenced at the time of analysis (Supplementary Table S1 available in JGV Online). Neighbourjoining (NJ) and maximum-parsimony (MP) analyses were performed using MEGA, version 3.1 (Kumar et al, 2004).…”

“…Eighteen structural protein genes are conserved in 26 lepidopteran baculoviruses that have been sequenced (Herniou et al, 2003;Jehle et al, 2006). Only 17 of these genes were identified in the MaviNPV genome, including basic DNA-binding protein p6.9 (ORF77); capsid-associated proteins vp39 (ORF67), vp1054 (ORF40) and vp91/p95 (ORF66); occlusion-derived virus (ODV)-associated proteins tegument protein gp41 (ORF63) and p74 (ORF106); ODV envelope proteins odve18 (ORF111), odv-e25 (ORF71), odv-e27 (ORF112) and odv-e56 (ORF116); occlusion body matrix polh (ORF1); per os infectivity factors pif-1 (ORF91), pif-2 (ORF13) and pif-3 (ORF89); as well as protein kinase-1 (pk-1; ORF3), efp/ld130 (ORF14) and fp25K (ORF45).…”

“…The family Baculoviridae is subdivided into two genera, Nucleopolyhedrovirus (NPV) and Granulovirus (GV). Based on the polyhedrin (polh) gene, NPVs are further subdivided into group I and group II (Bulach et al, 1999;Herniou et al, 2001Herniou et al, , 2003. Recent evidence shown from the comparison of 29 baculovirus genomes indicates that baculovirus phylogeny is aligned with the classification of the hosts more closely than with morphological traits (Afonso et al, 2001;Garcia-Maruniak et al, 2004;Lauzon et al, 2004;Jehle et al, 2006).…”