Genus: Betabaculovirus


Genus: Betabaculovirus

Distinguishing features 

OBs are generally ovocylindrical in shape, measure approximately 0.12 × 0.50 µm, and characteristically contain one virion (Tanada and Hess 1991) (Figure 1.Betabaculovirus). Each ODV virion typically contains a single nucleocapsid within a single envelope. Occluded virions may mature among nuclear-cytoplasmic cellular contents after loss of the nuclear membrane of infected cells. Uncoating is thought to occur by a mechanism in which viral DNA is extruded into the nucleus through the nuclear pore while the capsid remains in the cytoplasm (Summers 1971, Au et al., 2013).

Figure 1.Betabaculovirus. Occlusion bodies of baculoviruses in the genus Betabaculovirus.  Scanning electron micrograph of Spodoptera frugiperda granulovirus occlusion bodies (A, courtesy of J. R. Adams), and transmission electron micrographs of Mythimna unipuncta granulovirus B occlusion bodies (B and C), showing their unique ovocylindrical shape. Scale bars: (A) 2 µm; (B, C) 100 nm. 

Virion

See discussion under family properties.

Genome organization and replication 

See discussion under family properties.

Biology

Members of this genus have been isolated only from the insect order Lepidoptera.

Species demarcation criteria

Traditionally, species distinctions have been broadly based on host range and specificity, DNA restriction profiles, DNA sequences from various regions of the genome, and predicted protein sequence similarities.  More recently, species demarcation criteria for alpha- and betabaculoviruses have been proposed that rely upon pairwise nucleotide distances estimated with the Kimura-2-parameter substitution model from partial sequences of three conserved baculovirus genes: late expression factor-8 (lef-8) and late expression factor-9 (lef-9), which encode subunits of the baculovirus RNA polymerase, and polyhedrin/granulin (polh/gran), which encodes the viral occlusion body matrix protein (Jehle et al., 2006). If nucleotide distances between two viruses at these loci are less than 0.015 substitutions/site, the two baculoviruses are considered to belong to the same species. If nucleotide distances between two viruses are greater than 0.05 substitutions/site, the viruses are considered to belong to different species. If the nucleotide distances lie between 0.015 and 0.050 substitutions/site, additional characteristics of the two viruses (i.e. host range) must be considered to make a decision about their taxonomic status. The proposed criteria were originally based on an alignment of sequences from 117 separate baculovirus isolates and the phylogeny inferred from this alignment. Researchers have applied this criterion to other isolates to identify many new baculovirus species and variants of currently recognized species.

Member Species

SpeciesVirus name(s)Exemplar isolateExemplar accession numberExemplar RefSeq numberAvailable sequenceOther isolatesOther isolate accession numbersVirus Abbreviation(s)Isolate Abbreviation
Adoxophyes orana granulovirusAdoxophyes orana granulovirusEnglishAF547984NC_005038Complete genomeAdorGV
Agrotis segetum granulovirusAgrotis segetum granulovirusDAKR584663Complete genomeAgseGV
Artogeia rapae granulovirusPieris rapae granulovirus WuhanWuhanGQ884143NC_013797Complete GenomePiraGV
Choristoneura fumiferana granulovirusChoristoneura occidentalis granulovirusDQ333351NC_008168Complete genomeChocGV
Clostera anachoreta granulovirusClostera anachoreta granulovirusHBHNHQ116624NC_015398Complete genomeClanGV
Clostera anastomosis granulovirus AClostera anastomosis granulovirus AHenanKC179784NC_022646Complete genomeClasGV-A
Clostera anastomosis granulovirus BClostera anastomosis granulovirus BKR091910Complete genomeClasGV-B
Cnaphalocrocis medinalis granulovirusCnaphalocrocis medinalis granulovirusEnpingKU593505Complete genomeCnmeGV
Cryptophlebia leucotreta granulovirusCryptophlebia leucotreta granulovirusCV3AY229987NC_005068Complete genomeCrleGV
Cydia pomonella granulovirusCydia pomonella granulovirusM1U53466NC_002816Complete genomeCpGV
Diatraea saccharalis granulovirusDiatraea saccharalis granulovirusParanaKP296186NC_028491Complete genomeDisaGV
Epinotia aporema granulovirusEpinotia aporema granulovirusJN408834NC_018875Complete genomeEpapGV
Erinnyis ello granulovirusErinnyis ello granulovirusS86KJ406702NC_025257Complete genomeErelGV
Harrisina brillians granulovirusHarrisina brillians granulovirusM2AF142425Partial genomeHbGV
Helicoverpa armigera granulovirusHelicoverpa armigera granulovirusEU255577NC_010240Complete genomeHearGV
Lacanobia oleracea granulovirusLacanobia oleracea granulovirusS1Y08294Partial genomeLaolGV
Mythimna unipuncta granulovirus APseudaletia unipuncta granulovirusHawaiianEU678671NC_013772Complete genomePsunGV
Mythimna unipuncta granulovirus BMythimna unipuncta granulovirus8KX855660Complete genomeMyunGV
Phthorimaea operculella granulovirusPhthorimaea operculella granulovirusTAF499596NC_004062Complete genomePhopGV
Plodia interpunctella granulovirusPlodia interpunctella granulovirusCambridgeKX151395NC_032225Complete genomePiGV
Plutella xylostella granulovirusPlutella xylostella granulovirusK1AF270937NC_002593Complete genomePlxyGV
Spodoptera frugiperda granulovirusSpodoptera frugiperda granulovirusVG008KM371112NC_026511Complete genomeSpfrGV
Spodoptera litura granulovirusSpodoptera litura granulovirusK1DQ288858NC_009503Complete genomeSpltGV
Trichoplusia ni granulovirusTrichoplusia ni granulovirusLBIV-12KU752557Complete genomeTnGV
Xestia c-nigrum granulovirusXestia c-nigrum granulovirusalpha4AF162221NC_002331Complete genomeXecnGV

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

Related, Unclassified Viruses 

Virus name

Accession number

Virus abbreviation

Mocis latipes granulovirus

KR011718

MolaGV

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