Distinguishing features
Occlusion bodies typically measure 0.5 to 5 µm in size and are generally polyhedral, although morphology may vary and size may reach 15 µm (Adams and McClintock 1991). They mature within the nuclei of infected cells and characteristically contain many enveloped virions (Figure 1.Alphabaculovirus). The occluded virions are packaged with either single or multiple nucleocapsids within a single viral envelope. Members of some virus species manifest both phenotypes. A number of genes that influence nucleocapsid packaging are known, but in members of some species, packaging may be variable (Rohrmann 2014, Yang et al., 2014). Single (S) and multiple (M) designations in common names have been retained for species where variability has not been reported and for distinct viruses that would otherwise have identical designations under the current nomenclature. During viral entry, nucleocapsids are transported through the nuclear membrane and into the nucleus (Au et al., 2016), where uncoating and viral replication occur.
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Figure 1.Alphabaculovirus. Occlusion bodies of baculoviruses in the genus Alphabaculovirus. Scanning electron micrographs of Autographa californica multiple nucleopolyhedrovirus (A) and Operophtera brumata nucleopolyhedrovirus (B) occlusion bodies are shown, along with transmission electron micrographs of Autographa californica multiple nucleopolyhedrovirus (C) and Trichoplusia ni single nucleopolyhedrovirus (D) occlusion bodies containing occlusion-derived virus consisting of multiple and single nucleocapsids per envelope, respectively. Scale bars: (A, B) 2 µm; (C, D) 0.5 µm. Micrographs in panels (A) and (D) courtesy of J. R. Adams (USDA). |
Virion
Morphology
See family description. Nucleocapsid length appears to be proportional to genome size (Fraser 1986).
Genome organization and replication
In addition to the family Baculoviridae core genes, the alphabaculoviruses and betabaculoviruses appear to share an additional 23 homologs (Garavaglia et al., 2012).
Biology
Species 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., 2006b). 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. A more recent examination of pairwise nucleotide distances for all 38 baculovirus core genes among 172 completely sequenced baculovirus genomes has confirmed the current species classification based on pairwise distances for lef-8, lef-9, and polh loci (Wennmann et al., 2018).
Member species
Species | Virus name | Isolate | Accession number | RefSeq number | Available sequence | Virus Abbrev. | |
---|---|---|---|---|---|---|---|
Adoxophyes honmai nucleopolyhedrovirus | Adoxophyes honmai nucleopolyhedrovirus | ADN001 | AP006270 | NC_004690 | Complete genome | AdhoNPV | |
Agrotis ipsilon multiple nucleopolyhedrovirus | Agrotis ipsilon multiple nucleopolyhedrovirus | Illinois | EU839994 | NC_011345 | Complete genome | AgipMNPV | |
Agrotis segetum nucleopolyhedrovirus A | Agrotis segetum nucleopolyhedrovirus A | Polish | DQ123841 | NC_007921 | Complete genome | AgseNPV-A | |
Agrotis segetum nucleopolyhedrovirus B | Agrotis segetum nucleopolyhedrovirus B | English | KM102981 | NC_025960 | Complete genome | AgseNPV-B | |
Alphabaculovirus ardigramma | Artaxa digramma nucleopolyhedrovirus | MN233792 | Complete genome | ArdiNPV | |||
Alphabaculovirus dijuno | Dione juno nucleopolyhedrovirus | MK558262 | Complete genome | DijuNPV | |||
Alphabaculovirus ranu | Rachiplusia nu nucleopolyhedrovirus | MK419956 | Complete genome | RanuNPV | |||
Alphabaculovirus speridania-b | Spodoptera eridania nucleopolyhedrovirus | MT040195 | Complete genome | SperNPV | |||
Antheraea pernyi nucleopolyhedrovirus | Antheraea pernyi nucleopolyhedrovirus | Liaoning | DQ486030 | NC_008035 | Complete genome | AnpeNPV | |
Anticarsia gemmatalis multiple nucleopolyhedrovirus | Anticarsia gemmatalis multiple nucleopolyhedrovirus | 2D | DQ813662 | NC_008520 | Complete genome | AgMNPV | |
Anticarsia gemmatalis multiple nucleopolyhedrovirus | Anticarsia gemmatalis multiple nucleopolyhedrovirus | 37 | KR815466 | Complete genome | AgMNPV | ||
Autographa californica multiple nucleopolyhedrovirus | Autographa californica multiple nucleopolyhedrovirus | C6 | L22858 | NC_001623 | Complete genome | AcMNPV | |
Autographa californica multiple nucleopolyhedrovirus | Plutella xylostella multiple nucleopolyhedrovirus | CL3 | DQ457003 | Complete genome | PlxyMNPV | ||
Bombyx mori nucleopolyhedrovirus | Bombyx mori nucleopolyhedrovirus | T3 | L33180 | NC_001962 | Complete genome | BmNPV | |
Bombyx mori nucleopolyhedrovirus | Bombyx mandarina nucleopolyhedrovirus | S1 | FJ882854 | Complete genome | BomaNPV | ||
Buzura suppressaria nucleopolyhedrovirus | Buzura suppressaria nucleopolyhedrovirus | Hubei | KF611977 | NC_023442 | Complete genome | BuzuNPV | |
Catopsilia pomona nucleopolyhedrovirus | Catopsilia pomona nucleopolyhedrovirus | 416 | KU565883 | NC_030240 | Complete genome | CapoNPV | |
Choristoneura fumiferana DEF multiple nucleopolyhedrovirus | Choristoneura fumiferana DEF multiple nucleopolyhedrovirus | AY327402 | NC_005137 | Complete genome | CfDEFMNPV | ||
Choristoneura fumiferana multiple nucleopolyhedrovirus | Choristoneura fumiferana multiple nucleopolyhedrovirus | Ireland | AF512031 | NC_004778 | Complete genome | CfMNPV | |
Choristoneura murinana nucleopolyhedrovirus | Choristoneura murinana nucleopolyhedrovirus | Darmstadt | KF894742 | NC_023177 | Complete genome | ChmuNPV | |
Choristoneura rosaceana nucleopolyhedrovirus | Choristoneura rosaceana nucleopolyhedrovirus | NB_1 | KC961304 | NC_021924 | Complete genome | ChroNPV | |
Chrysodeixis chalcites nucleopolyhedrovirus | Chrysodeixis chalcites nucleopolyhedrovirus | AY864330 | NC_007151 | Complete genome | ChchNPV | ||
Chrysodeixis includens nucleopolyhedrovirus | Pseudoplusia includens single nucleopolyhedrovirus | IE | KJ631622 | NC_026268 | Complete genome | PsinSNPV | |
Clanis bilineata nucleopolyhedrovirus | Clanis bilineata nucleopolyhedrovirus | DZ1 | DQ504428 | NC_008293 | Complete genome | ClbiNPV | |
Condylorrhiza vestigialis nucleopolyhedrovirus | Condylorrhiza vestigialis multiple nucleopolyhedrovirus | PR.2002 | KJ631623 | NC_026430 | Complete genome | CoveMNPV | |
Cryptophlebia peltastica nucleopolyhedrovirus | Cryptophlebia peltastica nucleopolyhedrovirus | SA | MH394321 | Complete genome | CrpeNPV | ||
Cyclophragma undans nucleopolyhedrovirus | Cyclophragma undans nucleopolyhedrovirus | Whiov | KT957089 | Complete genome | CyunNPV | ||
Ectropis obliqua nucleopolyhedrovirus | Ectropis obliqua nucleopolyhedrovirus | A1 | DQ837165 | NC_008586 | Complete genome | EcobNPV | |
Epiphyas postvittana nucleopolyhedrovirus | Epiphyas postvittana nucleopolyhedrovirus | AY043265 | NC_003083 | Complete genome | EppoNPV | ||
Euproctis pseudoconspersa nucleopolyhedrovirus | Euproctis pseudoconspersa nucleopolyhedrovirus | Hangzhou | FJ227128 | NC_012639 | Complete genome | EupsNPV | |
Helicoverpa armigera nucleopolyhedrovirus | Helicoverpa armigera nucleopolyhedrovirus | G4 | AF271059 | NC_002654 | Complete genome | HearNPV | |
Helicoverpa armigera nucleopolyhedrovirus | Helicoverpa armigera nucleopolyhedrovirus | C1 | AF303045 | Complete genome | HearNPV | ||
Helicoverpa armigera nucleopolyhedrovirus | Helicoverpa armigera nucleopolyhedrovirus | NNg1 | AP010907 | Complete genome | HearNPV | ||
Hemileuca species nucleopolyhedrovirus | Hemileuca sp. nucleopolyhedrovirus | MEM | KF158713 | NC_021923 | Complete genome | HespNPV | |
Hyphantria cunea nucleopolyhedrovirus | Hyphantria cunea nucleopolyhedrovirus | N9 | AP009046 | NC_007767 | Complete genome | HycuPV | |
Hyposidra talaca nucleopolyhedrovirus | Hyposidra talaca nucleopolyhedrovirus | India.001 | MH261376 | Complete genome | HytaNPV | ||
Lambdina fiscellaria nucleopolyhedrovirus | Lambdina fiscellaria nucleopolyhedrovirus | GR15 | KP752043 | NC_026922 | Complete genome | LafiNPV | |
Leucania separata nucleopolyhedrovirus | Leucania separata nucleopolyhedrovirus | AH1 | AY394490 | NC_008348 | Complete genome | LeseNPV | |
Lonomia obliqua nucleopolyhedrovirus | Lonomia obliqua multiple nucleopolyhedrovirus | SP/2000 | KP763670 | NC_043520 | Complete genome | LoobNPV | |
Lymantria dispar multiple nucleopolyhedrovirus | Lymantria dispar multiple nucleopolyhedrovirus | 5-6 | AF081810 | NC_001973 | Complete genome | LdMNPV | |
Lymantria xylina nucleopolyhedrovirus | Lymantria xylina multiple nucleopolyhedrovirus | 5 | GQ202541 | NC_013953 | Complete genome | LyxyMNPV | |
Mamestra brassicae multiple nucleopolyhedrovirus | Mamestra brassicae multiple nucleopolyhedrovirus | K1 | JQ798165 | NC_023681 | Complete genome | MbMNPV | |
Mamestra configurata nucleopolyhedrovirus A | Mamestra configurata nucleopolyhedrovirus A | 90/2 | U59461 | NC_003529 | Complete genome | MacoNPV-A | |
Mamestra configurata nucleopolyhedrovirus A | Mamestra configurata nucleopolyhedrovirus A | 90/4 | AF539999 | Complete genome | MacoNPV-A | ||
Mamestra configurata nucleopolyhedrovirus B | Mamestra configurata nucleopolyhedrovirus B | 96B | AY126275 | NC_004117 | Complete genome | MacoNPV-B | |
Maruca vitrata nucleopolyhedrovirus | Maruca vitrata nucleopolyhedrovirus | MV-8 | EF125867 | NC_008725 | Complete genome | MaviNPV | |
Mythimna unipuncta nucleopolyhedrovirus A | Mythimna unipuncta nucleopolyhedrovirus | #7 | MF375894 | NC_043530 | Complete genome | MyunNPV | |
Mythimna unipuncta nucleopolyhedrovirus B | Mythimna unipuncta nucleopolyhedrovirus | KY310 | MH124167 | Complete genome | MyunNPV | ||
Operophtera brumata nucleopolyhedrovirus | Operophtera brumata nucleopolyhedrovirus | MA | MF614691 | NC_040621 | Complete genome | OpbuNPV | |
Orgyia leucostigma nucleopolyhedrovirus | Orgyia leucostigma nucleopolyhedrovirus | CFS-77 | EU309041 | NC_010276 | Complete genome | OrleNPV | |
Orgyia pseudotsugata multiple nucleopolyhedrovirus | Orgyia pseudotsugata multiple nucleopolyhedrovirus | U75930 | NC_001875 | Complete genome | OpMNPV | ||
Oxyplax ochracea nucleopolyhedrovirus | Oxyplax ochracea nucleopolyhedrovirus | 435 | MF143631 | NC_043529 | Complete genome | OxocNPV | |
Peridroma saucia nucleopolyhedrovirus | Peridroma species nucleopolyhedrovirus | GR167 | KM009991 | NC_024625 | Complete genome | PespNPV | |
Perigonia lusca nucleopolyhedrovirus | Perigonia lusca single nucleopolyhedrovirus | KM596836 | NC_027923 | Complete genome | PeluSNPV | ||
Spodoptera eridania nucleopolyhedrovirus | Spodoptera eridania nucleopolyhedrovirus | 251 | MH320559 | Complete genome | SperNPV | ||
Spodoptera exempta nucleopolyhedrovirus | Spodoptera exempta nucleopolyhedrovirus | "244,1" | MH717816 | Complete genome | SpexNPV | ||
Spodoptera exigua multiple nucleopolyhedrovirus A | Spodoptera exigua multiple nucleopolyhedrovirus | US1 | AF169823 | NC_002169 | Complete genome | SeMNPV | |
Spodoptera exigua multiple nucleopolyhedrovirus B | Spodoptera exigua multiple nucleopolyhedrovirus | QD | MH370144 | Complete genome | SeMNPV | ||
Spodoptera frugiperda multiple nucleopolyhedrovirus | Spodoptera frugiperda multiple nucleopolyhedrovirus | 3AP2 | EF035042 | NC_009011 | Complete genome | SfMNPV | |
Spodoptera littoralis nucleopolyhedrovirus | Spodoptera littoralis nucleopolyhedrovirus | AN1956 | JX454574 | NC_038369 | Complete genome | SpliNPV | |
Spodoptera litura nucleopolyhedrovirus | Spodoptera litura nucleopolyhedrovirus | G2 | AF325155 | NC_003102 | Complete genome | SpltNPV | |
Sucra jujuba nucleopolyhedrovirus | Sucra jujuba nucleopolyhedrovirus | 473 | KJ676450 | NC_028636 | Complete genome | SujuNPV | |
Thysanoplusia orichalcea nucleopolyhedrovirus | Thysanoplusia orichalcea nucleopolyhedrovirus | p2 | JX467702 | NC_019945 | Complete genome | ThorNPV | |
Trichoplusia ni single nucleopolyhedrovirus | Trichoplusia ni single nucleopolyhedrovirus | DQ017380 | NC_007383 | Complete genome | TnSNPV | ||
Urbanus proteus nucleopolyhedrovirus | Urbanus proteus nucleopolyhedrovirus | Southern Brazil | KR011717 | NC_029997 | Complete genome | UrprNPV | |
Wiseana signata nucleopolyhedrovirus | Wiseana signata nucleopolyhedrovirus | AF016916 | NC_038370 | Partial genome | WisiNPV |
Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.
Related, unclassified viruses
Virus name |
Accession number |
Virus abbreviation |
Apocheima cinerarium nucleopolyhedrovirus |
ApciNPV |
|
Cerapteryx graminis nucleopolyhedrovirus |
HQ603182, HQ603183, HQ603184 |
CegrNPV |
Dasychira pudibunda nucleopolyhedrovirus |
DapuNPV-ML1 |
|
Helicoverpa armigera multiple nucleopolyhedrovirus |
HearMNPV |
|
Lacanobia oleracea nucleopolyhedrovirus |
LaolNPV |
|
Leucoma salicis multiple nucleopolyhedrovirus |
AY729808, AY729809, AY729810 |
LesaMNPV |
Malacosoma californicum pluviale nucleopolyhedrovirus |
McplNPV |
|
Malacosoma neustria nucleopolyhedrovirus |
AY519243, AY519244, AY519245 |
ManeNPV |
Operophtera bruceata nucleopolyhedrovirus |
KY064005, KY064007 |
OpbrNPV |
Orgyia pseudotsugata single nucleopolyhedrovirus |
AY895150, AY895151, AY895152, AY895153 |
OpSNPV |
Panolis flammea nucleopolyhedrovirus |
PaflNPV |
|
Philosamia cynthia nucleopolyhedrovirus |
PhcyNPV |
|
Rachiplusia ou multiple nucleopolyhedrovirus |
AY145471=NC_004323 |
RoMNPV-R1 |
Spodoptera litura nucleopolyhedrovirus II |
EU780426=NC_011616 |
SpltNPV-II |