Analysis of the genome of Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV-19) and of the high genomic heterogeneity in group II nucleopolyhedroviruses.
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.
Wolff
José Luiz Caldas
JLC
Laboratório de Virologia Molecular, Núcleo Integrado de Biotecnologia, Universidade de Mogi das Cruzes, Mogi das Cruzes, SP, Brazil.
Valicente
Fernando Hercos
FH
Embrapa Milho e Sorgo, Sete Lagoas, MG, Brazil.
Martins
Renata
R
Embrapa Milho e Sorgo, Sete Lagoas, MG, Brazil.
Oliveira
Juliana Velasco de Castro
JVC
Laboratório de Evolução Molecular e Bionformática, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, SP, Brazil.
Zanotto
Paolo Marinho de Andrade
PMA
Laboratório de Evolução Molecular e Bionformática, Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, SP, Brazil.
D000818:Animals; D001938:Brazil; D016000:Cluster Analysis; D004279:DNA, Viral / Q000235:genetics; D023061:Gene Order; D018740:Genetic Heterogeneity; D016679:Genome, Viral; D005838:Genotype; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000145:classification* / Q000235:genetics*; D016366:Open Reading Frames; D010802:Phylogeny; D020161:Physical Chromosome Mapping; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D039104:RNA 3' Polyadenylation Signals; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D017385:Sequence Homology; D018411:Spodoptera; D026801:Synteny
D004279:DNA, Viral