Abbreviations : Report Help
Robert L. Harrison, Elisabeth A. Herniou, Johannes A. Jehle, David A. Theilmann4, John P. Burand, James J. Becnel, Peter J. Krell, Monique M. van Oers, Joseph D. Mowery and Gary R. Bauchan
A summary of this ICTV Report chapter has been published as an ICTV Virus Taxonomy Profile article in the Journal of General Virology, and should be cited when referencing this online chapter as follows:
Harrison, R.L., Herniou, E.A., Jehle, J.A., Theilmann, D.A., Burand, J.P., Becnel, J.J., Krell, P.J., M. van Oers, M., Mowery, J.D., Bauchan, G.R., and ICTV Report Consortium. 2019, ICTV Virus Taxonomy Profile: Baculoviridae, Journal of General Virology, 99: 1185–1186.
The Baculoviridae is a family of large, insect-specific viruses with circular dsDNA genomes ranging from 80 to 180 kbp. Virions consist of enveloped, rod-shaped nucleocapsids and are embedded in distinctive occlusion bodies measuring 0.15–5 µm. The occlusion bodies consist of a matrix composed of a single viral protein expressed at high levels during infection. Members of this family infect exclusively larvae of insect orders Lepidoptera, Hymenoptera and Diptera. Some members have been developed as biopesticides for controlling insect pests and as vectors for recombinant protein expression.
Table 1.Baculoviridae. Characteristics of the family Baculoviridae.
Autographa californica multiple nucleopolyhedrovirus C6 (L22858), species Autographa californica multiple nucleopolyhedrovirus, genus Alphabaculovirus
One or two distinct types of virions consisting of enveloped, rod-shaped nucleocapsids, 30–60 nm × 250–300 nm, containing >20 proteins
A single covalently-closed circular dsDNA molecule of 80–180 kbp encoding 100–200 proteins
Nuclear, with nucleocapsids assembled in the nucleus and enveloped either (a) in the nucleus or mixed nucleoplasm and cytoplasm, or (b) upon budding through the plasma membrane
From mRNAs transcribed from viral DNA
Larval-stage insects of orders Diptera, Hymenoptera, and Lepidoptera
Four genera with 76 species
One or two virion phenotypes are involved in baculovirus infections. Infection is initiated in the gut epithelium by virions contained within a crystalline protein occlusion body (OB) which may be polyhedral in shape and containing many virions (members of the genera Alphabaculovirus, Gammabaculovirus and Deltabaculovirus); or ovocylindrical and containing only one, or rarely two or more, virions (members of the genus Betabaculovirus). Virions within occlusions, referred to as occlusion-derived virus (ODV), consist of one or more rod-shaped nucleocapsids that have a distinct structural polarity and are enclosed within an envelope (Figure 1.Baculoviridae). For ODV, nucleocapsid envelopment occurs within the nucleus (members of the genus Alphabaculovirus) or in the nuclear-cytoplasmic milieu after loss of the nuclear membrane (members of the genus Betabaculovirus). Nucleocapsids average 30–60 nm in diameter and 250–300 nm in length. Spike-like structures (peplomers) have not been reported on envelopes of ODV. Virions of the second phenotype (termed budded virus or BV; Figure 1.Baculoviridae) are generated when nucleocapsids bud through the plasma membrane at the surface of infected cells. BVs typically contain a single nucleocapsid. Their envelopes are derived from the cellular plasma membrane and characteristically appear as a loose-fitting membrane that contains an envelope fusion glycoprotein (EFP), which forms peplomers usually observed at one end of the virion (see “Proteins”, below).
ODV buoyant density in CsCl is 1.18–1.25 g cm−3, and that of the nucleocapsid is 1.47 g cm−3. BV buoyant density in sucrose is 1.17–1.18 g cm−3 (Summers and Volkman 1976). Virions of both phenotypes are sensitive to organic solvents and detergents. ODV and BV are marginally sensitive to heat and inactivated at extreme pH values (Gudauskas and Canerday 1968, Knittel and Fairbrother 1987).
Nucleocapsids contain one molecule of circular, supercoiled dsDNA of 80–180 kbp (Figure 1.Baculoviridae, Figure 2.Baculoviridae).
Genomic analyses suggest that baculoviruses encode approximately 100–200 proteins. Proteomics analyses to date indicate that virions may contain as few as 23 and as many as 73 different polypeptides (Deng et al., 2007, Zhang et al., 2015). Nucleocapsids from both virion phenotypes (ODV and BV) contain a major capsid protein (VP39), a basic DNA-binding protein (P6.9) complexed with the viral genome, and at least 2–3 additional proteins. Two different EFPs have been identified to date. The EFP GP64 is present in a group of alphabaculoviruses that include Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and close relatives (Blissard and Wenz 1992). Most of the alphabaculoviruses and betabaculoviruses encode and appear to utilize EFPs known as F proteins, which are homologs of the Ld130 protein from Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) (Pearson et al., 2001) and the Se8 protein from Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) (IJkel et al., 2000). The deltabaculovirus Culex nigripalpus nucleopolyhedrovirus also encodes an EFP with fusogenic activity (Wang et al., 2017). Several ODV envelope proteins have been identified. Eight ODV proteins, including P74 (Faulkner et al., 1997), PIF-1 (Kikhno et al., 2002), PIF-2 (Pijlman et al., 2003), PIF-3 (Ohkawa et al., 2005), AC96 (PIF-4) (Fang et al., 2009), ODV-E56 (PIF-5) (Harrison et al., 2010), AC68 (PIF-6) (Nie et al., 2012), AC110 (PIF-7) (Jiantao et al., 2016), and AC83 (PIF-8) (Javed et al., 2017) are essential for oral infectivity of ODV. The major protein of the OB matrix is a virus-encoded polypeptide of 25–33 kDa. This protein is called polyhedrin for nucleopolyhedroviruses (the common name used for the alpha-, delta- and gammabaculoviruses) and granulin for granuloviruses (betabaculoviruses) (Rohrmann 1986). The OB is often surrounded by an envelope that contains at least one major protein (Whitt and Manning 1988). The polyhedrin protein of deltabaculoviruses is serologically and genetically unrelated to OB proteins of the alpha-, beta- and gammabaculoviruses (Perera et al., 2006).
Lipids are present in the envelopes of ODV and BV. Lipid composition differs between the two virion phenotypes (Braunagel and Summers 1994).
Carbohydrates are present as glycoproteins and glycolipids.
Circular genomic DNA is infectious, suggesting that after cellular entry and uncoating, no virion-associated proteins are essential for infection (Burand et al., 1980, Carstens et al., 1980). Thirty-eight gene homologs, the so-called baculovirus core genes, are shared among alpha-, beta-, gamma- and deltabaculoviruses (Javed et al., 2017, Garavaglia et al., 2012) (Figure 2.Baculoviridae). These conserved genes are involved in various functions, including DNA replication, late gene transcription and virion structure. In some cases, larger genome sizes may result from the presence of families of repeated genes (Hayakawa et al., 1999). Transcription of baculovirus genes is temporally regulated, and two main classes of genes are recognized: early and late. Late genes may be further subdivided into late and very late genes. Gene classes (early, late and very late) are not clustered on the baculovirus genome, and both strands of the genome are involved in coding functions. Early genes are transcribed by host RNA polymerase II, whereas late and very late genes are transcribed by an alpha-amanitin-resistant viral RNA polymerase (Huh and Weaver 1990). RNA splicing occurs, but appears to be rare (Chisholm and Henner 1988, Pearson and Rohrmann 1997). Transient early and late gene transcription and DNA replication studies suggest that at least three virus-encoded proteins regulate early gene transcription (Guarino and Summers 1986, Kovacs et al., 1991, Lu and Carstens 1993, Yoo and Guarino 1994), whereas approximately 20 viral encoded proteins known as late expression factors (LEFs) are necessary for late gene transcription (Rapp et al., 1998, Huijskens et al., 2004). Of the approximately 20 LEFs, half appear to be involved in DNA replication (Lu and Miller 1995). Late gene transcription initiates at the second adenine of a conserved 5′-TAAG-3′ promoter motif, which is an essential core element of the baculovirus late promoter (Chen et al., 2013). Putative replication origins consist of repeated sequences found at multiple locations within the baculovirus genome (Pearson et al., 1992, Hilton and Winstanley 2007). These sequences, termed homologous repeat (hr) regions, do not appear to be highly conserved among different baculovirus species. Single copy, non-hr putative replication origins have also been identified (Kool et al., 1994). DNA replication is required for late gene transcription. Most virion structural proteins are encoded by late genes. While transcription of late and very late genes appears to begin immediately after DNA replication, some very late genes that encode occlusion body-specific proteins are transcribed at extremely high levels at a later time (Thiem and Miller 1990). BV production occurs primarily during the late phase, and occlusion body production occurs during the very late phase.
In infected animals, viral replication begins in the insect midgut. Following ingestion, OBs are solubilized in the gut lumen, releasing the ODVs, which are thought to enter the target epithelial cells via fusion with the plasma membrane at the cell surface (Kawanishi et al., 1972). In lepidopteran insects, viral entry into midgut cells occurs in an alkaline environment, up to pH 12. Infection of the midgut is required for initiation of infection in the animal. Although the virus is believed to undergo one round of replication in the midgut epithelium prior to transmission of infection to secondary tissues within the hemocoel, a mechanism for direct movement from the midgut to the hemocoel has also been proposed (Granados and Lawler 1981, Washburn et al., 1999, Washburn et al., 2003).
DNA replication takes place in the nucleus. In betabaculovirus-infected cells, the integrity of the nuclear membrane is lost during the replication process (Walker et al., 1982, Federici and Stern 1990). With some baculoviruses, replication is restricted to the gut epithelium and progeny virions become enveloped and occluded within these cells, and may be shed into the gut lumen with sloughed epithelium, or released upon death of the host (Federici and Stern 1990). In other baculoviruses, the infection is transmitted to internal organs and tissues (Keddie et al., 1989). The second virion phenotype, BV, which buds from the basolateral membrane of infected gut cells, is required for transmission of the infection into the hemocoel. Infected fat body cells are the primary location of occluded virus production in lepidopteran insects. Occluded virus matures within nuclei of infected cells for alpha-, gamma- and deltabaculoviruses, and within the nuclear-cytoplasmic milieu for betabaculoviruses. OBs containing infectious ODV virions are released upon death, and usually liquefaction, of the host.
Antigenic determinants that cross-react between different baculoviruses exist on virion proteins and on the major OB polypeptide: polyhedrin or granulin (Summers et al., 1978, Volkman 1983). Neutralizing antibodies react with the major surface glycoprotein of BVs (Volkman et al., 1984).
Baculoviruses have been isolated from insects only - primarily from insects of the order Lepidoptera, but also from the orders Hymenoptera and Diptera. Transmission naturally occurs (i) horizontally by contamination with OBs of food, egg surfaces, etc. (Hamm and Young 1974, Young and Yearian 1986); (ii) vertically within the egg either from infected female or male adults (Doane 1969); or experimentally; (iii) by injection of intact hosts with BVs; or (iv) by infection or transfection of cell cultures. Typically, the infection process in a permissive insect host requires approximately one week, and, as an end result, the diseased insect liquefies, releasing infectious occlusion bodies into the environment. OBs represent an environmentally stable form of the virus with increased resistance to chemical and physical decay as well as inactivation by UV light. Persistent, asymptomatic infections have also been documented (Myers and Cory 2016).
Genera of Baculoviridae are distinguished on the basis of phylogeny, genome characteristics (especially gene content), host range and OB morphology (Jehle et al., 2006a).
Alpha, Beta, Gamma, Delta: Greek letters α, β, γ, and δ, the first four letters of the Greek alphabet.
Baculo-: from baculum, meaning “rod” in latin, referring to the morphology of the nucleocapsid.
Granulo-: from “granule” and “granulosis”, referring to the relatively small size of OBs and their granular appearance in betabaculovirus-infected cells.
Nucleopolyhedro-: from “nuclear polyhedrosis” and “polyhedron”, referring to the multifaceted appearance of OBs in the nuclei of infected cells.
Phylogenetic analysis based on the 38 baculovirus core genes shows that the family comprises four monophyletic groups (Figure 3.Baculoviridae), which can also be discriminated based on the orders of their insect hosts and on their morphology. Baculoviruses are classified into the four genera Alphabaculovirus, Betabaculovirus, Gammabaculovirus and Deltabaculovirus.
Members of the family Baculoviridae share structural, genetic and biological characters with viruses of family Nudiviridae, which had been formerly classified as “non-occluded” baculoviruses. The nudiviruses share at least 20 core genes with baculoviruses (Wang et al., 2011). Baculoviruses are also similar to the salivary gland hypertrophy viruses of Hytrosaviridae, and share at least 12 core genes with members of this family (Jehle et al., 2013).
OBs measure 0.15 to 5 µm in size and are generally polyhedral, although morphology may vary (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.
Nucleocapsid length appears to be proportional to genome size (Fraser 1986).
In addition to the family Baculoviridae core genes, the alphabaculoviruses and betabaculoviruses appear to share an additional 23 homologs (Garavaglia et al., 2012).
Species of this genus have been isolated only from the insect order Lepidoptera.
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).
Apocheima cinerarium nucleopolyhedrovirus
Cerapteryx graminis nucleopolyhedrovirus
Condylorrhiza vestigialis multiple nucleopolyhedrovirus
Dasychira pudibunda nucleopolyhedrovirus
Helicoverpa armigera multiple nucleopolyhedrovirus
Lacanobia oleracea nucleopolyhedrovirus
Leucoma salicis multiple nucleopolyhedrovirus
Malacosoma californicum pluviale nucleopolyhedrovirus
Malacosoma neustria nucleopolyhedrovirus
Orgyia pseudotsugata single nucleopolyhedrovirus
Panolis flammea nucleopolyhedrovirus
Philosamia cynthia nucleopolyhedrovirus
Rachiplusia ou multiple nucleopolyhedrovirus
Spodoptera litura nucleopolyhedrovirus II
Urbanus proteus nucleopolyhedrovirus
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).
See discussion under family description.
Members of this genus have been isolated only from the insect order Lepidoptera.
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.
Only a single species (Culex nigripalpus nucleopolyhedrovirus) has been classified in this genus. Replication of Culex nigripalpus nucleopolyhedrovirus (CuniNPV) is restricted to host midgut epithelium, primarily in larval stages but rarely in adults. Two virion phenotypes may be characteristic of a virus species. Virions of the ODV phenotype are embedded within an occlusion body composed of a crystalline matrix of a single viral protein with no homology to polyhedrin or granulin proteins of other baculovirus genera (Perera et al., 2006, Moser et al., 2001). Each occlusion body ranges in size from 0.5 to 5 µm and contains few (1–4) or many (>50) singly-enveloped virions depending on the strain of virus, lacks the polyhedron envelope of other baculoviruses, and matures within nuclei of infected cells (Figure 1.Deltabaculovirus).
The CuniNPV genome is 108,252 bp and encodes at least 109 putative proteins, some of which have sequence homology with those from other baculoviruses (Afonso et al., 2001). Homologous proteins are involved in early and late gene expression, DNA replication, as well as structural and auxiliary functions. Gene orientation, order, and content in the genome of CuniNPV is different from the members of other baculovirus genera.
Transmission of CuniNPV to larval mosquitoes is strongly influenced by divalent cations: Mg2+ is a potent enhancer of transmission whereas Ca2+ is a strong inhibitor (Becnel et al., 2001). Hosts include at least three genera of mosquitoes, but other mosquito genera and families of Diptera are likely hosts.
Only a single species has been classified for this genus, although other isolates that likely represent new species have been reported (Becnel and White 2007). It is possible that criteria based on alignments of conserved gene sequences can be developed (de Araujo Coutinho et al., 2012).
Aedes sollicitans nucleopolyhedrovirus
Uranotaenia sapphrinia nucleopolyhedrovirus
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.
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.
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.
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.
Gilpinia hercyniae nucleopolyhedrovirus
Neodiprion abietis nucleopolyhedrovirus
Robert L. Harrison*Baculoviridae Study Group Chair Invasive Insect Biocontrol and Behavior Laboratory Beltsville Agricultural Research Center USDA Agricultural Research Service Beltsville MD 20705 USA Tel: 301-504-5249 E-mail: Robert.L.Harrison@ars.usda.gov
Elisabeth A. Herniou Institut de Recherche sur la Biologie de l’Insecte CNRS UMR 7261 Université François Rabelais Tours 37200 France Tel: +33 247 367381 E-mail: email@example.com
Johannes A. Jehle Julius Kühn Institute Federal Research Centre for Cultivated Plants Institute for Biological Control Darmstadt 64287 Germany Tel: +49 (0)6151 407 220 E-mail: firstname.lastname@example.org
David A. Theilmann Summerland Research and Development Centre Agriculture and Agri-Food Canada Summerland BC V0H 1Z0 Canada Tel: 250-494-6395 E-mail: email@example.com
John P. Burand Department of Microbiology University of Massachusetts-Amherst Amherst MA 01003 USA Tel: 413-545-3629 E-mail: firstname.lastname@example.org
James J. Becnel Center for Medical, Agricultural and Veterinary Entomology USDA Agricultural Research Service Gainesville FL 32608 USA Tel: 352-374-5961 E-mail: James.Becnel@ars.usda.gov
Peter J. Krell Department of Molecular and Cellular Biology University of Guelph Guelph Ontario N1G 2W1 Canada Tel: 519-824-4120 x53368 or 53264 E-mail: email@example.com
Monique M. van Oers Laboratory of Virology Wageningen University Wageningen 6709 PD The Netherlands Tel: +31317485082 E-mail: firstname.lastname@example.org
Joseph D. Mowery Electron and Confocal Microscopy Unit Beltsville Agricultural Research Center USDA Agricultural Research Service Beltsville MD 20705 USA Tel: 301-504-9027 E-mail: Joseph.email@example.com
Gary R. Bauchan Electron and Confocal Microscopy Unit Beltsville Agricultural Research Center USDA Agricultural Research Service Beltsville MD 20705 USA Tel: 301-504-6649 E-mail: firstname.lastname@example.org
* To whom correspondence should be addressed
The chapter in the Ninth ICTV Report, which served as the template for this chapter, was contributed by Herniou, E.A., Arif, B.M., Becnel, J.J., Blissard, G.W., Bonning, B., Harrison, R., Jehle, J.A., Theilmann, D.A. and Vlak, J.M.
Baculovirus Molecular Biology, 3rd edition: https://www.ncbi.nlm.nih.gov/books/NBK114593/
Tree file (newick format)
Alignment file (FASTA format)
Individual gene alignment pre-concatenation (ZIP)
Braunagel, S. C. & Summers, M. D. (2007). Molecular biology of the baculovirus occlusion-derived virus envelope. Curr Drug Targets 8, 1084-1095. [PubMed]
Herniou, E. A. & Jehle, J. A. (2007). Baculovirus phylogeny and evolution. Curr Drug Targets 8, 1043-1050. [PubMed]
Herniou, E. A., Olszewski, J. A., Cory, J. S. & O'Reilly, D. R. (2003). The genome sequence and evolution of baculoviruses. Annu Rev Entomol 48, 211-234. [PubMed]
Miller, L. K. (1997). The Baculoviruses. New York: Plenum Press.
van Oers, M. M. & Vlak, J. M. (2007). Baculovirus genomics. Curr Drug Targets 8, 1051-1068. [PubMed]
Adams, J. R. & McClintock, J. T. (1991). Baculoviridae. Nuclear polyhedrosis viruses. In Atlas of Invertebrate Viruses, pp. 87-226. Edited by J. R. Adams & J. R. Bonami. Boca Raton, Florida: CRC Press, Inc.
Afonso, C. L., Tulman, E. R., Lu, Z., Balinsky, C. A., Moser, B. A., Becnel, J. J., Rock, D. L. & Kutish, G. F. (2001). Genome sequence of a baculovirus pathogenic for Culex nigripalpus. J Virol 75, 11157-11165. [PubMed]
Arif, B., Escasa, S. & Pavlik, L. (2011). Biology and genomics of viruses within the genus Gammabaculovirus. Viruses 3, 2214-2222. [PubMed]
Au, S., Wu, W. & Pante, N. (2013). Baculovirus nuclear import: open, nuclear pore complex (NPC) sesame. Viruses 5, 1885-1900. [PubMed]
Au, S., Wu, W., Zhou, L., Theilmann, D. A. & Pante, N. (2016). A new mechanism for nuclear import by actin-based propulsion used by a baculovirus nucleocapsid. J Cell Sci 129, 2905-2911. [PubMed]
Becnel, J., White, S., Moser, B., Fukuda, T., Rotstein, M., Undeen, A. & Cockburn, A. (2001). Epizootiology and transmission of a newly discovered baculovirus from the mosquitoes Culex nigripalpus and C. quinquefasciatus. J Gen Virol 82, 275-282. [PubMed]
Becnel, J. J. & White, S. E. (2007). Mosquito pathogenic viruses - the last 20 years. J Am Mosq Control Assoc 23, 36-49. [PubMed]
Blissard, G. W. & Wenz, J. R. (1992). Baculovirus gp64 envelope glycoprotein is sufficient to mediate pH-dependent membrane fusion. J Virol 66, 6829-6835. [PubMed]
Braunagel, S. C. & Summers, M. D. (1994). Autographa californica nuclear polyhedrosis virus, PDV, and ECV viral envelopes and nucleocapsids: structural proteins, antigens, lipid and fatty acid profiles. Virology 202, 315-328. [PubMed]
Burand, J. P., Summers, M. D. & Smith, G. E. (1980). Transfection with baculovirus DNA. Virology 101, 286-290. [PubMed]
Carstens, E. B., Tjia, S. T. & Doerfler, W. (1980). Infectious DNA from Autographa californica nuclear polyhedrosis virus. Virology 101, 311-314. [PubMed]
Chen, Y. R., Zhong, S., Fei, Z., Hashimoto, Y., Xiang, J. Z., Zhang, S. & Blissard, G. W. (2013). The transcriptome of the baculovirus Autographa californica multiple nucleopolyhedrovirus in Trichoplusia ni cells. J Virol 87, 6391-6405. [PubMed]
Chisholm, G. E. & Henner, D. J. (1988). Multiple early transcripts and splicing of the Autographa californica nuclear polyhedrosis virus IE-1 gene. J Virol 62, 3193-3200. [PubMed]
de Araujo Coutinho, C. J., Alves, R., Sanscrainte, N. D., de Barros Pinto Viviani, A., Dos Santos, P. F., de Souza, P. A., de Carvalho-Mello, I. M. & Becnel, J. J. (2012). Occurrence and phylogenetic characterization of a baculovirus isolated from Culex quinquefasciatus in Sao Paulo State, Brazil. Arch Virol 157, 1741-1745. [PubMed]
Deng, F., Wang, R., Fang, M., Jiang, Y., Xu, X., Wang, H., Chen, X., Arif, B. M., Guo, L., Wang, H. & Hu, Z. (2007). Proteomics analysis of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus identified two new occlusion-derived virus-associated proteins, HA44 and HA100. J Virol 81, 9377-9385. [PubMed]
Doane, C. C. (1969). Trans-ovum transmission of a nuclear-polyhedrosis virus in the gypsy moth and the inducement of virus susceptibility. J Invertebr Pathol 14, 199-210.
Fang, M., Nie, Y., Harris, S., Erlandson, M. A. & Theilmann, D. A. (2009). Autographa californica multiple nucleopolyhedrovirus core gene ac96 encodes a per os infectivity factor (PIF-4). J Virol 83, 12569-12578. [PubMed]
Faulkner, P., Kuzio, J., Williams, G. V. & Wilson, J. A. (1997). Analysis of p74, a PDV envelope protein of Autographa californica nucleopolyhedrovirus required for occlusion body infectivity in vivo. J Gen Virol 78 ( Pt 12), 3091-3100. [PubMed]
Federici, B. A. & Stern, V. M. (1990). Replication and occlusion of a granulosis virus in larval and adult midgut epithelium of the western grapeleaf skeletonizer, Harrisina brillians. J Invertebr Pathol 56, 401-414.
Fraser, M. (1986). Ultrastructural observations of virion maturation in Autographa californica nuclear polyhedrosis virus infected Spodoptera frugiperda cell cultures. Journal of Ultrastructure and Molecular Structure Research 95, 189-195.
Garavaglia, M. J., Miele, S. A., Iserte, J. A., Belaich, M. N. & Ghiringhelli, P. D. (2012). The ac53, ac78, ac101, and ac103 genes are newly discovered core genes in the family Baculoviridae. J Virol 86, 12069-12079. [PubMed]
Granados, R. R. & Lawler, K. A. (1981). In vivo pathway of Autographa californica baculovirus invasion and infection. Virology 108, 297-308. [PubMed]
Guarino, L. A. & Summers, M. D. (1986). Functional mapping of a trans-activating gene required for expression of a baculovirus delayed-early gene. J Virol 57, 563-571. [PubMed]
Gudauskas, R. T. & Canerday, D. (1968). The effect of heat, buffer salt and H-ion concentration, and ultraviolet light on the infectivity of heliothis and trichoplusia nuclear-polyhedrosis viruses. J Invertebr Pathol 12, 405-411. [PubMed]
Hamm, J. J. & Young, J. R. (1974). Mode of transmission of nuclear-polyhedrosis virus to progeny of adult Heliothis zea. J Invertebr Pathol 24, 70-81. [PubMed]
Harrison, R. L., Sparks, W. O. & Bonning, B. C. (2010). Autographa californica multiple nucleopolyhedrovirus ODV-E56 envelope protein is required for oral infectivity and can be substituted functionally by Rachiplusia ou multiple nucleopolyhedrovirus ODV-E56. J Gen Virol 91, 1173-1182. [PubMed]
Hayakawa, T., Ko, R., Okano, K., Seong, S. I., Goto, C. & Maeda, S. (1999). Sequence analysis of the Xestia c-nigrum granulovirus genome. Virology 262, 277-297. [PubMed]
Hilton, S. & Winstanley, D. (2007). Identification and functional analysis of the origins of DNA replication in the Cydia pomonella granulovirus genome. J Gen Virol 88, 1496-1504. [PubMed]
Huh, N. E. & Weaver, R. F. (1990). Identifying the RNA polymerases that synthesize specific transcripts of the Autographa californica nuclear polyhedrosis virus. J Gen Virol 71 ( Pt 1), 195-201. [PubMed]
Huijskens, I., Li, L., Willis, L. G. & Theilmann, D. A. (2004). Role of AcMNPV IE0 in baculovirus very late gene activation. Virology 323, 120-130. [PubMed]
IJkel, W., Westenberg, M., Goldbach, R. W., Blissard, G. W., Vlak, J. M. & Zuidema, D. (2000). A novel baculovirus envelope fusion protein with a proprotein convertase cleavage site. Virology 275, 30-41. [PubMed]
Javed, M. A., Biswas, S., Willis, L. G., Harris, S., Pritchard, C., van Oers, M. M., Donly, B. C., Erlandson, M. A., Hegedus, D. D. & Theilmann, D. A. (2017). Autographa californica multiple nucleopolyhedrovirus AC83 is a per os infectivity factor (PIF) protein required for occlusion-derived virus (ODV) and budded virus nucleocapsid assembly as well as assembly of the PIF complex in ODV envelopes. J Virol 91, pii: e02115-02116. [PubMed]
Jehle, J. A., Abd-Alla, A. M. & Wang, Y. (2013). Phylogeny and evolution of Hytrosaviridae. J Invertebr Pathol 112 Suppl, S62-67. [PubMed]
Jehle, J. A., Blissard, G. W., Bonning, B. C., Cory, J. S., Herniou, E. A., Rohrmann, G. F., Theilmann, D. A., Thiem, S. M. & Vlak, J. M. (2006a). On the classification and nomenclature of baculoviruses: a proposal for revision. Arch Virol 151, 1257-1266. [PubMed]
Jehle, J. A., Lange, M., Wang, H., Hu, Z., Wang, Y. & Hauschild, R. (2006b). Molecular identification and phylogenetic analysis of baculoviruses from Lepidoptera. Virology 346, 180-193. [PubMed]
Jiantao, L., Zhu, L., Zhang, S., Deng, Z., Huang, Z., Yuan, M., Wu, W. & Yang, K. (2016). The Autographa californica multiple nucleopolyhedrovirus ac110 gene encodes a new per os infectivity factor. Virus Res 221, 30-37. [PubMed]
Kawanishi, C. Y., Summers, M. D., Stoltz, D. B. & Arnott, H. J. (1972). Entry of an insect virus in vivo by fusion of viral envelope and microvillus membrane. J Invertebr Pathol 20, 104-108. [PubMed]
Keddie, B. A., Aponte, G. W. & Volkman, L. E. (1989). The pathway of infection of Autographa californica nuclear polyhedrosis virus in an insect host. Science 243, 1728-1730. [PubMed]
Kikhno, I., Gutierrez, S., Croizier, L., Croizier, G. & Ferber, M. L. (2002). Characterization of pif, a gene required for the per os infectivity of Spodoptera littoralis nucleopolyhedrovirus. J Gen Virol 83, 3013-3022. [PubMed]
Knittel, M. D. & Fairbrother, A. (1987). Effects of temperature and pH on survival of free nuclear polyhedrosis virus of Autographa californica. Appl Environ Microbiol 53, 2771-2773. [PubMed]
Kool, M., Goldbach, R. W. & Vlak, J. M. (1994). A putative non-hr origin of DNA replication in the HindIII-K fragment of Autographa californica multiple nucleocapsid nuclear polyhedrosis virus. J Gen Virol 75, 3345-3352. [PubMed]
Kovacs, G. R., Guarino, L. A. & Summers, M. D. (1991). Novel regulatory properties of the IE1 and IE0 transactivators encoded by the baculovirus Autographa californica multicapsid nuclear polyhedrosis virus. J Virol 65, 5281-5288. [PubMed]
Lu, A. & Carstens, E. B. (1993). Immediate-early baculovirus genes transactivate the p143 gene promoter of Autographa californica nuclear polyhedrosis virus. Virology 195, 710-718. [PubMed]
Lu, A. & Miller, L. K. (1995). The roles of eighteen baculovirus late expression factor genes in transcription and DNA replication. J Virol 69, 975-982. [PubMed]
Moser, B., Becnel, J., White, S., Afonso, C., Kutish, G., Shanker, S. & Almira, E. (2001). Morphological and molecular evidence that Culex nigripalpus baculovirus is an unusual member of the family Baculoviridae. J Gen Virol 82, 283-297. [PubMed]
Myers, J. H. & Cory, J. S. (2016). Ecology and evolution of pathogens in natural populations of Lepidoptera. Evol Appl 9, 231-247. [PubMed]
Nie, Y., Fang, M., Erlandson, M. A. & Theilmann, D. A. (2012). Analysis of the autographa californica multiple nucleopolyhedrovirus overlapping gene pair lef3 and ac68 reveals that AC68 is a per os infectivity factor and that LEF3 is critical, but not essential, for virus replication. J Virol 86, 3985-3994. [PubMed]
Ohkawa, T., Washburn, J. O., Sitapara, R., Sid, E. & Volkman, L. E. (2005). Specific binding of Autographa californica M nucleopolyhedrovirus occlusion-derived virus to midgut cells of Heliothis virescens larvae is mediated by products of pif genes Ac119 and Ac022 but not by Ac115. J Virol 79, 15258-15264. [PubMed]
Pearson, M., Bjornson, R., Pearson, G. & Rohrmann, G. (1992). The Autographa californica baculovirus genome: evidence for multiple replication origins. Science 257, 1382-1384. [PubMed]
Pearson, M. N. & Rohrmann, G. F. (1997). Splicing is required for transactivation by the immediate early gene 1 of the Lymantria dispar multinucleocapsid nuclear polyhedrosis virus. Virology 235, 153-165. [PubMed]
Pearson, M. N., Russell, R. L. & Rohrmann, G. F. (2001). Characterization of a baculovirus-encoded protein that is associated with infected-cell membranes and budded virions. Virology 291, 22-31. [PubMed]
Perera, O. P., Valles, S. M., Green, T. B., White, S., Strong, C. A. & Becnel, J. J. (2006). Molecular analysis of an occlusion body protein from Culex nigripalpus nucleopolyhedrovirus (CuniNPV). J Invertebr Pathol 91, 35-42. [PubMed]
Pijlman, G. P., Pruijssers, A. J. & Vlak, J. M. (2003). Identification of pif-2, a third conserved baculovirus gene required for per os infection of insects. J Gen Virol 84, 2041-2049. [PubMed]
Rapp, J. C., Wilson, J. A. & Miller, L. K. (1998). Nineteen baculovirus open reading frames, including LEF-12, support late gene expression. J Virol 72, 10197-10206. [PubMed]
Rohrmann, G. F. (1986). Polyhedrin structure. J Gen Virol 67, 1499-1513. [PubMed]
Rohrmann, G. F. (2014). Baculovirus nucleocapsid aggregation (MNPV vs SNPV): an evolutionary strategy, or a product of replication conditions? Virus Genes 49, 351-357. [PubMed]
Summers, M. D. (1971). Electron microscopic observations on granulosis virus entry, uncoating and replication processes during infection of the midgut cells of Trichoplusia ni. J Ultrastruct Res 35, 606-625. [PubMed]
Summers, M. D. & Volkman, L. E. (1976). Comparison of biophysical and morphological properties of occluded and extracellular nonoccluded baculovirus from in vivo and in vitro host systems. J Virol 17, 962-972. [PubMed]
Summers, M. D., Volkman, L. E. & Hsieh, C. (1978). Immunoperoxidase detection of baculovirus antigens in insect cells. J Gen Virol 40, 545-557. [PubMed]
Tanada, Y. & Hess, R. T. (1991). Baculoviridae. Granulosis viruses. In Atlas of Invertebrate Viruses, pp. 227-257. Edited by J. R. Adams & J. R. Bonami. Boca Raton, Florida: CRC Press, Inc.
Thiem, S. M. & Miller, L. K. (1990). Differential gene expression mediated by late, very late and hybrid baculovirus promoters. Gene 91, 87-94. [PubMed]
Volkman, L. E. (1983). Occluded and budded Autographa californica nuclear polyhedrosis virus: immunological relatedness of structural proteins. J Virol 46, 221-229. [PubMed]
Volkman, L. E., Goldsmith, P. A., Hess, R. T. & Faulkner, P. (1984). Neutralization of budded Autographa californica NPV by a monoclonal antibody: identification of the target antigen. Virology 133, 354-362. [PubMed]
Walker, S., Kawanishi, C. Y. & Hamm, J. J. (1982). Cellular pathology of a granulosis virus infection. J Ultrastruct Res 80, 163-177. [PubMed]
Wang, M., Shen, S., Wang, H., Hu, Z., Becnel, J. & Vlak, J. M. (2017). Deltabaculoviruses encode a functional type I budded virus envelope fusion protein. J Gen Virol 98, 847-852. [PubMed]
Wang, Y., Bininda-Emonds, O. R., van Oers, M. M., Vlak, J. M. & Jehle, J. A. (2011). The genome of Oryctes rhinoceros nudivirus provides novel insight into the evolution of nuclear arthropod-specific large circular double-stranded DNA viruses. Virus Genes 42, 444-456. [PubMed]
Washburn, J. O., Chan, E. Y., Volkman, L. E., Aumiller, J. J. & Jarvis, D. L. (2003). Early synthesis of budded virus envelope fusion protein GP64 enhances Autographa californica multicapsid nucleopolyhedrovirus virulence in orally infected Heliothis virescens. J Virol 77, 280-290. [PubMed]
Washburn, J. O., Lyons, E. H., Haas-Stapleton, E. J. & Volkman, L. E. (1999). Multiple nucleocapsid packaging of Autographa californica nucleopolyhedrovirus accelerates the onset of systemic infection in Trichoplusia ni. J Virol 73, 411-416. [PubMed]
Wennmann, J. T., Keilwagen, J. & Jehle, J. A. (2018). Baculovirus Kimura two-parameter species demarcation criterion is confirmed by the distances of 38 core gene nucleotide sequences. J Gen Virol 99, 1307-1320. [PubMed]
Whitt, M. A. & Manning, J. S. (1988). A phosphorylated 34-kDa protein and a subpopulation of polyhedrin are thiol linked to the carbohydrate layer surrounding a baculovirus occlusion body. Virology 163, 33-42. [PubMed]
Yang, M., Wang, S., Yue, X. L. & Li, L. L. (2014). Autographa californica multiple nucleopolyhedrovirus orf132 encodes a nucleocapsid-associated protein required for budded-virus and multiply enveloped occlusion-derived virus production. J Virol 88, 12586-12598. [PubMed]
Yoo, S. & Guarino, L. A. (1994). The Autographa californica nuclear polyhedrosis virus ie2 gene encodes a transcriptional regulator. Virology 202, 746-753. [PubMed]
Young, S. & Yearian, W. (1986). Movement of a nuclear polyhedrosis virus from soil to soybean and transmission in Anticarsia gemmatalis (Hübner)(Lepidoptera: Noctuidae) populations on soybean. Environ Entomol 15, 573-580.
Zhang, X., Liang, Z., Yin, X. & Shao, X. (2015). Proteomic analysis of the occlusion-derived virus of Clostera anachoreta granulovirus. J Gen Virol 96, 2394-2404. [PubMed]
Harrison, R.L., Herniou, E.A., Jehle, J.A., Theilmann, D.A., Burand, J.P., Becnel, J.J., Krell, P.J., M. van Oers, M., Mowery, J.D., Bauchan, G.R., and ICTV Report Consortium. 2019, ICTV Virus Taxonomy Profile: Baculoviridae, Journal of General Virology, 99: 1185–1186.
Support for preparation of the Online Report and Report Summaries has been provided by: