Analysis of the genome of Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV-19) and of the high genomic heterogeneity in group II nucleopolyhedroviruses

Abstract

The genome of the most virulent among 22 Brazilian geographical isolates of Spodoptera frugiperda nucleopolyhedrovirus, isolate 19 (SfMNPV-19), was completely sequenced and shown to comprise 132 565 bp and 141 open reading frames (ORFs). A total of 11 ORFs with no homology to genes in the GenBank database were found. Of those, four had typical baculovirus promoter motifs and polyadenylation sites. Computer-simulated restriction enzyme cleavage patterns of SfMNPV-19 were compared with published physical maps of other SfMNPV isolates. Differences were observed in terms of the restriction profiles and genome size. Comparison of SfMNPV-19 with the sequence of the SfMNPV isolate 3AP2 indicated that they differed due to a 1427 bp deletion, as well as by a series of smaller deletions and point mutations. The majority of genes of SfMNPV-19 were conserved in the closely related Spodoptera exigua NPV (SeMNPV) and Agrotis segetum NPV (AgseMNPV-A), but a few regions experienced major changes and rearrangements. Synthenic maps for the genomes of group II NPVs revealed that gene collinearity was observed only within certain clusters. Analysis of the dynamics of gene gain and loss along the phylogenetic tree of the NPVs showed that group II had only five defining genes and supported the hypothesis that these viruses form ten highly divergent ancient lineages. Crucially, more than 60 % of the gene gain events followed a power-law relation to genetic distance among baculoviruses, indicative of temporal organization in the gene accretion process.

Two viruses that cause salivary gland hypertrophy in Glossina pallidipes and Musca domestica are related and form a distinct phylogenetic clade

“…2). A comparable level of collinearity has also been observed when several representatives of the baculovirus NPVs group II were compared (Wolff et al, 2008). A total of 161 conserved regions (not ORFs) sharing amino acid identities of 25-73 % were found between MdSGHV and GpSGHV by the syntenic analysis.…”

“…The genomic organization of MdSGHV and GpSGHV was compared according to the gene order by gene parity plot analysis (Hu et al, 1998) and by the collinearity of conserved regions (not specifically ORFs) with a syntenic map (Lauzon et al, 2006;Wolff et al, 2008). In both analyses, the two genomes were linearized taking the dnapol gene as the first ORF.…”

“…The ACT has been a useful tool since 2001 to compare genomes (Cole et al, 2001) and has been applied successfully to test collinearity between baculovirus genomes (Lauzon et al, 2006; Oliveira A. Garcia-Maruniak and others et al, 2006;Wolff et al, 2008). The syntenic map between MdSGHV and GpSGHV showed significant collinearity between the two genomes (Fig.…”

Analagous Population Structures for Two Alphabaculoviruses Highlight a Functional Role for Deletion Mutants

“…The genomes of SfMNPV and SeMNPV are strikingly similar (14,15), with 72 to 85% nucleotide homology in colinear regions covering 30% of the genome, and with Ͼ85% of genes being shared; this has led researchers to suggest that these two viruses are closely related (16,17). The large-deletion genotypes present in a Floridan SeMNPV isolate, SeMNPV-US2 (SeUS2), were observed to share parallel genetic and phenotypic characteristics with an SfMNPV isolate from Nicaragua, SfMNPV-NIC (SfNIC) (18).…”

Stability of a Spodoptera frugiperda Nucleopolyhedrovirus Deletion Recombinant during Serial Passage in Insects

“…Natural populations of the fall armyworm Spodoptera frugiperda (Lepidoptera) suffer S. frugiperda multiple nucleopolyhedrovirus (SfMNPV) disease, and some SfMNPV isolates have the potential to control this pest (12,16,33,44). The complete genome sequences of two isolates have been published (16,44).…”