Nucleotide sequence and phylogenetic analyses of the DNA polymerase gene of Anticarsia gemmatalis nucleopolyhedrovirus

Genome of the most widely used viral biopesticide: Anticarsia gemmatalis multiple nucleopolyhedrovirus

The genome of Anticarsia gemmatalis multiple nucleopolyhedrovirus isolate 2D (AgMNPV-2D), which is the most extensively used virus pesticide in the world, was completely sequenced and shown to have 132 239 bp (G+C content 44.5 mol%) and to be capable of encoding 152 non-overlapping open reading frames (ORFs). Three ORFs were unique to AgMNPV-2D, one of which (ag31) had similarity to eukaryotic poly(ADP-ribose) polymerases. The lack of chiA and v-cath may explain some of the success and growth of the AgMNPV biological control programme, as it may explain the high recovery of polyhedra sequestered inside dead larvae in the field, which are collected and used for further application as biological pesticides in soybean fields. The genome organization was similar to that of the Choristoneura fumiferana defective MNPV (CfDefNPV). Most of the variation between the two genomes took place near highly repetitive regions, which were also closely associated with bro-coding regions. The separation of the NPVs into groups I and II was supported by: (i) a phenogram of the complete genomes of 28 baculovirus and Heliothis zea virus 1, (ii) the most parsimonious reconstruction of gene content along the phenograms and (iii) comparisons of genomic features. Moreover, these data also reinforced the notion that group I of the NPVs can be split further into the AgMNPV lineage (AgMNPV, CfDefNPV, Epiphyas postvittana NPV, Orgyia pseudotsugata MNPV and C. fumiferana MNPV), sharing eight defining genes, and the Autographa californica MNPV (AcMNPV) lineage (AcMNPV, Rachiplusia ou NPV and Bombyx mori NPV), sharing nine defining genes.

Identification, transcriptional and phylogenetic analysis of the DNA polymerase gene of Pieris rapae granulovirus

The DNA polymerase gene (dnapol) of the Pieris rapae granulovirus (PiraGV) was completely sequenced and located between 73.1 and 76 m.u. on the PiraGV genome. Its open reading frame (ORF) has 3135 nucleotides (35% G-C content) encoding 1045 amino acids with a predicted molecular mass of 122.16 kDa. Homology analysis indicated that PiraGV dnapol had 28-66% amino acid identity to that of other known baculoviruses. Comparative sequence analyses demonstrated that the PiraGV dnapol gene contains conserved 3'-5' exonuclease motifs and DNA binding functional domains of the DNA polymerase enzyme found in all known baculovirus dnapols. Northern blot results showed that in infected Pieris rapae larvae the PiraGV dnapol gene was transcribed as a predominant 3.7 kb mRNA. 5' and 3' RACE indicated that the PiraGV dnapol transcript was initiated from the thymine residue located at -378 nt upstream from the ATG start codon and terminated at the polyadenylation signal AATAAA. Phylogenetic analysis of dnapol sequences suggests that the PiraGV dnapol is more closely related to that of Cydia pomonella GV and Cryptophlebia leucotreta GV than to those of other baculoviruses.