The spheroidin of an entomopoxvirus isolated from the grasshopper Anacridium aegyptium (AaEPV) shares low homology with spheroidins from lepidopteran or coleopteran EPVs

Control of Pest Grasshoppers in North America

Grasshoppers (Orthoptera: Acrididae) frequently inflict damage on millions of hectares of western rangelands and crops. The main method of controlling grasshopper outbreaks consists of covering their infestations with chemical insecticides. Although it is relatively cheap, fast, and efficient, chemical control bears serious risks to human health, non-target organisms, and the environment. To overcome this challenge, biological control is a less environmentally hazardous alternative to traditional, synthetic insecticides. This paper reviews strategies that could be used as effective ways to control such pests with a special focus on effective bait formulations that might provide a key model in developing biological control strategies for the grasshopper population.

The complete genome sequence of the Alphaentomopoxvirus Anomala cuprea entomopoxvirus, including its terminal hairpin loop sequences, suggests a potentially unique mode of apoptosis inhibition and mode of DNA replication

Complete genome sequence of Anomala cuprea entomopoxvirus, which belongs to the genus Alphaentomopoxvirus, including its terminal hairpin loop sequences, is reported. This is the first genome sequence of Alphaentomopoxvirus reported, and hairpin loops in entomopoxviruses have not previously been sequenced. The genome is 245,717 bp, which is smaller than had previously been estimated for Alphaentomopoxvirus. The inverted terminal repeats are quite long, and experimental results suggest that one genome molecule has one type of hairpin at one end and another type at the other end. The genome contains unexpected ORFs, e.g., that for the ubiquitin-conjugating enzyme E2 of eukaryotes. The BIR and RING domains found in a single ORF for an inhibitor of apoptosis in baculoviruses and entomopoxviruses occurred in two different, widely separated ORFs. Furthermore, an ORF in the genome contains a serpin domain that was previously found in vertebrate poxviruses for apoptosis inhibition but not in insect viruses.

New insights into the evolution of Entomopoxvirinae from the complete genome sequences of four entomopoxviruses infecting Adoxophyes honmai, Choristoneura biennis, Choristoneura rosaceana, and Mythimna separata

Poxviruses are nucleocytoplasmic large DNA viruses encompassing two subfamilies, the Chordopoxvirinae and the Entomopoxvirinae, infecting vertebrates and insects, respectively. While chordopoxvirus genomics have been widely studied, only two entomopoxvirus (EPV) genomes have been entirely sequenced. We report the genome sequences of four EPVs of the Betaentomopoxvirus genus infecting the Lepidoptera: Adoxophyes honmai EPV (AHEV), Choristoneura biennis EPV (CBEV), Choristoneura rosaceana EPV (CREV), and Mythimna separata EPV (MySEV). The genomes are 80% AT rich, are 228 to 307 kbp long, and contain 247 to 334 open reading frames (ORFs). Most genes are homologous to those of Amsacta moorei entomopoxvirus and encode several protein families repeated in tandem in terminal regions. Some genomes also encode proteins of unknown functions with similarity to those of other insect viruses. Comparative genomic analyses highlight a high colinearity among the lepidopteran EPV genomes and little gene order conservation with other poxvirus genomes. As with previously sequenced EPVs, the genomes include a relatively conserved central region flanked by inverted terminal repeats. Protein clustering identified 104 core EPV genes. Among betaentomopoxviruses, 148 core genes were found in relatively high synteny, pointing to low genomic diversity. Whole-genome and spheroidin gene phylogenetic analyses showed that the lepidopteran EPVs group closely in a monophyletic lineage, corroborating their affiliation with the Betaentomopoxvirus genus as well as a clear division of the EPVs according to the orders of insect hosts (Lepidoptera, Coleoptera, and Orthoptera). This suggests an ancient coevolution of EPVs with their insect hosts and the need to revise the current EPV taxonomy to separate orthopteran EPVs from the lepidopteran-specific betaentomopoxviruses so as to form a new genus.

Comparative analysis of selected genes from Diachasmimorpha longicaudata entomopoxvirus and other poxviruses

The Diachasmimorpha longicaudata entomopoxvirus (DlEPV) is the first symbiotic EPV described from a parasitic wasp. The DlEPV is introduced into the tephritid fruit fly larval host along with the wasp egg at oviposition. We sequenced a shotgun genomic library of the DlEPV DNA and analyzed and compared the predicted protein sequences of eight ORFs with those of selected poxviruses and other organisms. BlastP searches showed that five of these are homologous to poxvirus putative proteins such as metalloprotease, a putative membrane protein, late transcription factor-3, virion surface protein, and poly (A) polymerase (PAP) regulatory small subunit. Three of these are similar to those of other organisms such as the gamma-glutamyltransferase (GGT) of Arabidopsis thaliana, eukaryotic initiation factor 4A (eIF4A) of Caenorhabditis briggsae and lambda phage integrase (lambda-Int) of Enterococcus faecium. Transcription motifs for early (TGA,A/T,XXXXA) or late (TAAATG, TAAT, or TAAAT) gene expression conserved in poxviruses were identified with those ORFs. Phylogenetic analysis of multiple alignments of five ORFs and 20 poxvirus homologous sequences and of a concatenate of multiple alignments suggested that DlEPV probably diverged from the ancestral node between the fowlpox virus and the genus B, lepidopteran and orthopteran EPVs, to which Amsacta moorei and Melanoplus sanguinipes EPV, respectively, belong. The DlEPV putative GGT, eIF4A, and lambda-Int contained many conserved domains that typified these proteins. These homologues may be involved in either viral pathogenicity or enhancing parasitism via the gamma-glutamyl cycle and compensation of eIF4A levels in the parasitized fly, or via the integration of a portion of the viral genome into the wasp and/or parasitized fly.