Genus: Gammabaculovirus


Genus: Gammabaculovirus

Distinguishing features

The nucleocapsids are enveloped singly, and multiple virions are assembled into each OB (Figure 1.Gammabaculovirus.). The virus is restricted to the host midgut and causes what was previously described in the literature as “infectious diarrhea”. Genome sequencing analyses of three viruses - Neodiprion lecontei nucleopolyhedrovirus (NeleNPV), Neodiprion sertifer nucleopolyhedrovirus (NeseNPV), and Neodiprion abietis nucleopolyhedrovirus (NeabNPV) - revealed that these viruses do not encode typical envelope fusion proteins found in other baculoviruses (Arif et al., 2011). This observation has raised the question of whether the budded virus phenotype plays a role in gammabaculovirus biology.

Figure 1.Gammabaculovirus. Transmission electron micrograph of occlusion bodies of Neodiprion abietis nucleopolyhedrovirus (micrograph courtesy of C.J. Lucarotti). Scale bar: 0.5 µm.

Virion 

See discussion under family properties.

Genome organization and replication

In comparison to other baculoviruses, the genomes of members of the genus Gammabaculovirus are relatively low in G+C content (about 33%). The genomes of the three sequenced gammabaculoviruses are collinear except for a large non-syntenic region between the DNA polymerase and polyhedrin genes. This region contains genes and ORFs not shared among the three characterized genomes.

Biology

Gammabaculoviruses of species defined to date infect sawfly larvae of genus Neodiprion, order Hymenoptera, but sawflies of other genera (e.g. Gilpinia) may also contain gammabaculoviruses.

Species demarcation criteria

The two species in this genus are distinguished on the basis of differences in host range and specificity, genome sequence, gene content and gene order.  It is unclear if the nucleotide distance-based criteria developed for alpha- and betabaculoviruses can be applied to gammabaculoviruses.

Member species

SpeciesVirus name(s)Exemplar isolateExemplar accession numberExemplar RefSeq numberAvailable sequenceOther isolatesOther isolate accession numbersVirus abbreviationIsolate abbreviation
Neodiprion lecontei nucleopolyhedrovirusNeodiprion lecontei nucleopolyhedrovirusAY349019NC_005906Complete genomeNeleNPV
Neodiprion sertifer nucleopolyhedrovirusNeodiprion sertifer nucleopolyhedrovirusAY430810NC_005905Complete genomeNeseNPV

Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.

Related, unclassified viruses

Virus name

Accession number

Virus abbreviation

Gilpinia hercyniae nucleopolyhedrovirus

AY449779, AY449800

GiheNPV

Neodiprion abietis nucleopolyhedrovirus

DQ317692

NeabNPV

Virus names and virus abbreviations, are not official ICTV designations.