Sequence and Organization of the Neodiprion lecontei Nucleopolyhedrovirus Genome

Abstract

All fully sequenced baculovirus genomes, with the exception of the dipteran Culex nigripalpus nucleopolyhedrovirus (CuniNPV), have previously been from Lepidoptera. This study reports the sequencing and characterization of a hymenopteran baculovirus, Neodiprion lecontei nucleopolyhedrovirus (NeleNPV), from the redheaded pine sawfly. NeleNPV has the smallest genome so far published (81,755 bp) and has a GC content of only 33.3%. It contains 89 potential open reading frames, 43 with baculovirus homologues, 6 identified by conserved domains, and 1 with homology to a densovirus structural protein. Average amino acid identity of homologues ranged from 19.7% with CuniNPV to 24.9% with Spodoptera exigua nucleopolyhedrovirus. The conserved set of baculovirus genes has dropped to 29, since NeleNPV lacks an F protein homologue (ac23/ ld130). NeleNPV contains 12 conserved lepidopteran baculovirus genes, including that for DNA binding protein, late expression factor 11 (lef-11), polyhedrin, occlusion derived virus envelope protein-18 (odv-e18), p40, and p45, but lacks 21 others, including lef-3, me53, immediate early gene-1, lef-6, pp31, odv-e66, few polyhedra 25k, odv-e25, protein kinase-1, fibroblast growth factor, and ubiquitin. The lack of identified baculovirus homologues may be due to difficulties in identification, differences in host-virus interactions, or other genes performing similar functions. Gene parity plots showed limited colinearity of NeleNPV with other baculoviruses, and phylogenetic analysis indicates that NeleNPV may have existed before the lepidopteran nucleopolyhedrovirus and granulovirus divergence. The creation of two new Baculoviridae genera to fit hymenopteran and dipteran baculoviruses may be necessary.

On the classification and nomenclature of baculoviruses: A proposal for revision

“…It follows the suggestion of Lauzon et al [23] and has the advantage that only the classification and nomenclature of genera are revised. The virus names at the species level remain unchanged.…”

“…This indicates that the phylogenetic distance between CuniNPV and lepidoperan NPVs is much greater than between lepidopteran NPVs and GVs (Table 2). Our current picture of baculovirus genome diversity was further advanced by the genome characterization of two viruses infecting hymenopteran hosts, the Neodiprion lecontei NPV (NeleNPV) and N. sertifer NPV (NeseNPV) [23,10]. These two viruses have relatively small genomes of only 82-86 kbp encoding about 90 ORFs.…”

Recent Advances in Our Knowledge of Baculovirus Molecular Biology and Its Relevance for the Registration of Baculovirus-Based Products for Insect Pest Population Control

“…Nudiviruses and baculoviruses, however, are thought to have shared a common ancestral virus (Wang & Jehle, 2009). Deltabaculoviruses and gammabaculoviruses are thought to be more primitive than the alphabaculoviruses and betabaculoviruses because of their smaller genomes and tissue tropism which is limited to midgut epithelial cells (Lauzon et al, 2004) and, in the case of deltabaculoviruses, cells of the posterior midgut and gastic caeca (Moser et al, 2001). Gammabaculoviruses, however, are thought to be more closely (although still distantly) related to the alphabaculoviruses and betabaculoviruses than are the deltabaculoviruses (Herniou et al, 2004).…”

“…Baculovirus genome sizes range from the smallest gammabaculovirus, Neodiprion lecontei nucleopolyhedrovirus (NeleNPV), at 81,755 bp (Lauzon et al, 2004) to the largest betabaculovirus, Xestia c-nigrum granulovirus (XcGV) at 178,733 bp (Hayakawa et al, 1999). No matter the genus or genome size, all baculoviruses share 31 core genes in common (Miele et al, 2011).…”

Genomic sequence and biological characterization of a nucleopolyhedrovirus isolated from the summer fruit tortrix, Adoxophyes orana

“…The NPVs are further classed into group I and II NPVs (Bulach et al, 1999;Zanotto et al, 1993). The majority of the sequenced NPVs infect insects of the Lepidopteran order, but NPVs that infect dipteran or hymenopteran insect species like the mosquito-infecting Culex nigripalpus NPV, or the NPVs from three Neodiprion species, have been sequenced (Afonso et al, 2001;Garcia-Maruniak et al, 2004;Lauzon et al, 2004; Duffy et al, 2006). Baculoviruses are used worldwide as biological control agents of agricultural and forest pests.…”