Ascoviridae - v201911


Ascoviridae - v201911

Ascoviridae

Sassan Asgari, Dennis K. Bideshi​, Yves Bigot​, Brian A. Federici​ and Xiao-Wen Cheng

Chapter contents

Posted December 2016

Ascoviridae: The family

Member taxa

Supporting information

Citation

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: 

Asgari, S., Bideshi, D.K., Bigot, Y., Federici, B.A., Cheng, X. and ICTV Report Consortium, 2017, ICTV Virus Taxonomy Profile: AscoviridaeJournal of General Virology, 98:45.

Summary

The family Ascoviridae includes viruses with circular dsDNA genomes of 100-200 kilobase pairs (kbp) characterized by oblong enveloped virions of 200-400 nm in length. Members of this family mainly infect lepidopteran larvae and are mechanically transmitted by parasitoid wasps in which they may also replicate. They cause high mortality among economically important insect pests thereby contributing to their natural ability to control insect populations.

Table 1.Ascoviridae. Characteristics of the family Ascoviridae.

Characteristic

Description

Typical member

Spodoptera frugiperda ascovirus 1a (AM398843), species Spodoptera frugiperda ascovirus 1a, genus Ascovirus

Virion

Enveloped, 130 nm in diameter by 200-400 nm in length, at least 20 polypeptides

Genome

100-200 kbp of circular dsDNA with 117-180 genes

Replication

Nuclear, with cell cleavage into virion-containing vesicles that turn the host haemolymph milky white

Translation

From transcribed mRNAs

Host Range

Lepidopteran insect larvae, mostly members of the family Noctuidae

Taxonomy

Two genera Ascovirus and Toursvirus

Members of this family are classified into two genera with distinct evolutionary lineages and genome characteristics:

Ascovirus. This genus includes three species whose members infect various members of the insect family Noctuidae, many species of which are economically important. Ascoviruses are difficult to transmit orally, and experimental studies as well as field observations indicate virions are mechanically transmitted horizontally by endoparasitic wasps of the families Braconidae and Ichneumonidae (Hymenoptera) through their contaminated ovipositor (Bideshi et al., 2010). 

Toursvirus. This genus includes only one species, Diadromus pulchellus toursvirus (previously named Diadromus pulchellus ascovirus 4a).  Diadromus pulchellus toursvirus (DpTV) is so far only found in species of the lepidopteran family Yponomeutidae, but it replicates also in its ichneumonid vector, Diadromus pulchellus. Replication in the wasp vector is limited in comparison to the titers produced in the lepidopteran host (Bigot et al., 1997a). In the wasp, DpTV is transmitted vertically when the virus genome is carried as unintegrated DNA in the nuclei of infected cells.

Virion

Morphology

Virions of ascoviruses are either bacilliform, ovoidal or allantoid in shape, and depending on the species, have complex symmetry, and are large, measuring approximately 130 nm in diameter by 200-400 nm in length. The virion consists of an inner particle surrounded by an outer envelope. The inner particle typically measures 80 x 300 nm and contains a DNA/protein core bounded by an apparent lipid bilayer, the external surface of which bears a distinctive layer of protein subunits. The virion, therefore, appears to contain two lipid membranes, one associated with the inner particle and the other forming the envelope. In negatively stained preparations, virions have a distinctive reticulate appearance thought to result from superimposition of protein subunits on the surface of the internal particle with those in the external envelope (Figure 1.Ascoviridae). Virions of DpTV of the genus Toursvirus have a similar size: about 220 nm long and 150 nm wide. They are multilayered, with two clear 7-nm-thick outer layers and one 15-nm-thick inner layer surrounding an electron-dense core (155-110 nm). However, the flattened rice-grain shape and fragility of the DpTV particles are unlike that of ascoviruses.

Figure 1.Ascoviridae: Morphology of ascovirus virions. A. Schematic illustration of the structure of a typical ascovirus virion. The virion consists of an inner particle and an outer envelope. The inner particle is complex and contains a DNA/protein core surrounded by an apparent unit membrane, the external surface of which bears a layer of distinctive protein subunits. B, C. Respectively, ultrathin longitudinal- and cross-sections through typical ascovirus virions (SfAV-1a). The dense inner layer corresponds with the distinctive layer of subunits shown in A. D to F. Negatively stained preparations of virions from three different ascovirus species: D, Spodoptera frugiperda ascovirus 1a (SfAV-1a); E, Trichoplusia ni ascovirus 2a (TnAV-2a), and F, Heliothis virescens ascovirus 3a (HvAV-3a). The reticulate appearance of the virions is thought to be due to the superimposition of top and bottom layers of the inner particle and the outer envelope. Bar = 50 nm.

Physicochemical and physical properties

Virions are sensitive to organic solvents and detergents.

Nucleic acid

The inner particle contains a single molecule of circular dsDNA ranging from 100 to 200 kbp. The G + C content ranges from 42% to 60% depending on the species. Ascovirus genomes contain from 117 to 180 genes, of which 40 are common among them (Bigot et al., 2009).

Proteins

Virions contain at least 20 proteins ranging in size from 6 to 200 kilodaltons (kDa) (Tan et al., 2009).

Lipids

Ultrastructural evidence and detergent sensitivity indicate the presence of lipid in both the outer envelope and inner particle of the virion. The specific lipid composition is not known.

Genome organization and replication

The genomes of five members of the genus Ascovirus, Heliothis virescens ascovirus 3e (HvAV-3e) (Asgari et al., 2007), HvAV-3f (Wei et al., 2014), HvAV-3g (Huang et al., 2012), Spodoptera frugiperda ascovirus 1a (SfAV-1a) (Bideshi et al., 2006) and Trichoplusia ni ascovirus 6a (TnAV-6a; previously named TnAV-2c) (Wang et al., 2006), and one member of the genus Toursvirus, Diadromus wulchellus toursvirus (DpTV) (Bigot et al., 2009) have been completely sequenced.

Members of the family Ascoviridae initiate replication in the nucleus. The nucleus enlarges and ruptures, after which the plasmalemma invaginates, forming internal membranous folds that cleave the cell into a cluster of virion-containing vesicles (Federici and Govindarajan 1990). Virion assembly becomes apparent after the nucleus ruptures. The first recognizable structural component of the virion to form is the multilaminar layer of the inner particle. Based on its ultrastructure, this layer consists of a unit membrane and an exterior layer of protein subunits. As the multilaminar layer forms, the dense DNA/protein core assembles along the inner surface. While this process continues, the allantoid, ovoidal or bacilliform shape of the inner particle becomes apparent. After the inner particle is assembled, it is enveloped by a membrane, synthesized de novo, or derived from cell membranes, within the cell or vesicle. In the case of SfAV-1a, virions are occluded in an occlusion body composed of minivesicles and protein (Federici et al., 1990).

Biology

Host range

Members of the Ascovirus genus cause disease in lepidopteran larvae and pupae, and have been reported most commonly from species of the family Noctuidae, including Trichoplusia ni, Heliothis virescens, Helicoverpa zea, Spodoptera frugiperda and Autographa precationis. TnAV-2a and HvAV-3a have been shown to have a broad experimental host range among larvae of the lepidopteran family Noctuidae, but the host range of SfAV-1a is restricted primarily to species of Spodoptera (Hamm et al., 1986). However, ascoviruses may have an expanded host range that includes non-noctuid insects. For example, recent studies have demonstrated that HvAV-3e is able to productively propagate in Crocidolomia pavonana and Plutella xylostella larva, lepidopteran species belonging to families Crambidae and Plutellidae, respectively (Smede et al., 2008, Furlong and Asgari 2010).

DpTV, the only member of the Toursvirus genus, so far has only been found in species of the lepidopteran family Yponomeutidae, in which it replicates extensively. There is also a limited replication of the virus in its ichneumonid vector, Diadromus pulchellus, but is substantially less than its replication in the lepidopteran host (Bigot et al., 1997a).

Transmission

Members of the family Ascoviridae are difficult to transmit orally, and experimental studies as well as field observations indicate most are transmitted horizontally by endoparasitic wasps (Hymenoptera), many species of which belong to the families Braconidae and Ichneumonidae (Federici and Govindarajan 1990, Tillman et al., 2004). During egg-laying, the ovipositor of female wasps becomes contaminated with virions and virion-containing vesicles that circulate in the blood (hemolymph) of infected caterpillars. Wasps contaminated in this manner subsequently transmit ascovirus virions to new caterpillar hosts during oviposition. DpTV is transmitted vertically in the wasp D. pulchellus when the virus genome is carried as extrachromosomal DNA in the nuclei of infected cells.

Geographical distribution

Members of the family Ascoviridae are known from the United States, Europe, Australia, Indonesia, Japan, China and Mexico, and likely occur worldwide, that is, wherever species of Lepidoptera and their hymenopteran parasites occur. These viruses cause a chronic, fatal disease that markedly retards larval development, but which typically exhibits little other gross pathology. This lack of easily recognizable gross pathology probably accounts for the lack of host records from many geographical regions.

Cytopathic effects

Members of the family Ascoviridae vary in tissue tropism, with some attacking most host tissues, such as TnAV-2a and HvAV-3a, whereas others, such as SfAV-1a, are restricted to the fat body (Federici and Govindarajan 1990). The unique property of ascovirus infection is a cytopathology in which host cells cleave to form virion-containing vesicles by a developmental process utilizing a modified form of apoptosis (Bideshi et al., 2005). Infection results in nuclear hypertrophy followed by lysis. The anucleate cell enlarges 5–10-fold and then cleaves into 10–30 virion-containing vesicles. Membranes delimiting vesicles form by invagination of the plasmalemma and membrane synthesis. Millions of vesicles (ca. 107–108 vesicles ml-1) accumulate in the hemolymph, turning it milky white. Opaque white hemolymph containing refractile virion vesicles is unique and diagnostic for ascovirus disease (Federici 1983).

Genus demarcation criteria

The following list of criteria is used to differentiate genera in the family:

  • Virion morphology
  • Phylogenetic analysis
  • Lack of DNA/DNA hybridization at low stringency
  • Host of isolation and experimental host range
  • Association with specific hymenopteran parasites, if apparent

The virions of most Ascovirus isolates are similar in size and shape (Federici et al., 1990), but the Toursvirus DpTV virions are more flattened rice-grain shape rather than allantoid found in other ascoviruses (Bigot et al., 1997b). There should be no DNA/DNA hybridization between members of the genera Ascovirus and Toursvirus. DpTV, as the sole member of Toursvirus, is mostly transmitted by the parasitoid wasp, Diadromous pulchellus, whereas members of the genus Ascovirus can be transmitted by a variety of parasitoid wasp species. DpTV has been mainly isolated from the host pupae in the lepidopteran family of Yponomeutidae, but members of the Ascovirus genus have been isolated mostly from larvae of the lepidopteran family Noctuidae.

Derivation of names

Asco: from the Greek for “sac”, referring to the virion-containing vesicles produced by cleavage of host cells, which are characteristic for all known viruses of this family.

Tours: from Tours, France, where DpTV was first isolated.

Phylogenetic relationships

The family appears to have evolved into two lineages in which DpTV sits within a lineage distinct to that of the Ascovirus genus (Piegu et al., 2015) (Figure 2.Ascoviridae).

Figure 2.Ascoviridae: Phylogenetic tree obtained with nine core proteins shared by the members of Ascoviridae, Iridoviridae and Marseilleviridae. The tree was calculated using Mafft or Muscle alignments curated with Gblock (parameters were: -t=p -e=-gb1 -b2=N -b3=40 -b4=2 -b5=a -v=120), except for the RNase III orthologues, for which the complete sequence alignment was used. Alignments of the homologues of HvAV-3g ORF1 (DNA polymerase), 11 (DNA-directed RNA polymerase), 15 (DEAD-like helicase), 70 (DNA-directed RNA polymerase II), 74 (hypothetical protein), 81 (hypothetical protein), 85 (serine/threonine protein kinase), 122 (ATPase), 160 (hypothetical protein) were concatenated and trees based on maximum likelihood were calculated with PhyML. Parameters used were WAG (substitution matrix), 0 (proportion of invariable sites), 7 in a, and 5 in f (number of relative substitution rate categories), and F (substitution model). The protein substitution model, the proportion of invariable sites, the number of relative substitution, number of rate categories and substitution model for ML trees were selected and evaluated by ProtTest 3. The best model was chosen on the basis of the Akaike Information Criterion. Numbers in italics at nodes indicate bootstrap values (%) retrieved from 1000 replicates. Branch lengths are proportional to genetic distances. The taxonomic levels from the genera to the families are indicated in the right margin including the non-official grouping of invertebrate iridoviruses (IIVs) and vertebrate iridoviruses (VIVs). Genome accession numbers are shown in brackets. Protein sequences used originate from 8 VIVs including 3 ranaviruses [Ambystoma tigrinum virus (ATV); frog virus 3 (FV3); grouper iridovirus (GIV)], three megalocytiviruses [infectious spleen and kidney necrosis virus (ISKNV); orange-spotted grouper iridovirus (OSGIV); rock bream iridovirus, isolate C1 (TSBIV)] and two lymphocystiviruses [lymphocystis disease virus 1 (LCDV); lymphocystis disease virus, isolate China (LCDV-C)], but also 7 IIVs [IIV3 (Aedes taeniorhynchus iridescent virus), 6 (Chilo iridescent virus), 9 (Wiseana iridescent virus), 22 (Simulium sp. iridescent virus A), 25, 30 (Helicoverpa zea iridescent virus) and 31 (Armadillidium vulgare iridescent virus), 4 ascoviruses (Diadromus pulchellus toursvirus (DpTV), Heliothis virescens ascovirus 3g (HvAV-3g), Trichoplusia ni ascovirus 6a (TnAV-6a), Spodoptera frugiperda ascovirus 1a (SfAV-1a)] and members of two species of Marseilleviridae, the Lausannevirus and the Cannes 8 virus. All these viruses are members of recognized species (except TnAV-6a which is still unclassified) and have their genomes fully sequenced. For more details please refer to (Piegu et al., 2015). Note: The genome of TnAV-2a is not available, therefore, it was not included in the tree. This phylogenetic tree and corresponding sequence alignment are available to download from the Resources page.

Similarity with other taxa

Phylogenetic analyses using nine core genes shared by the members of Ascoviridae, Iridoviridae and Marseilleviridae revealed that all iridoviruses and members of Ascoviridae have evolved from a common ancestor that they share with members of the family Marseilleviridae (Figure 2.Ascoviridae).


Genus: Ascovirus

Distinguishing features

Ascoviruses typically replicate in lepidopteran larvae of the family Noctuidae producing virion-containing vesicles, which give a milky white colouration to the haemolymph. Virions of ascoviruses are either bacilliform, ovoidal or allantoid in shape measuring 130 nm in diameter by 200–400 nm in length.

Virion

See discussion under family description.

Genome organization and replication 

See discussion under family description.

Biology

See discussion under family description.

Species demarcation criteria

The following list of characters is used in combination to differentiate species in the genus:

  • Phylogenetic position of genes encoding homologs of IIV6 ORFs 022L, 037L, 067R, 075L, 142R, 176R, 295L, 347L, 393L and 428L.
  • Presence or absence of occlusion bodies
  • Lack of DNA/DNA hybridization with other species at low stringency
  • Restriction enzyme fragment length polymorphisms (RFLPs)
  • Host of isolation and experimental host range
  • Tissue tropism
  • Association with specific hymenopteran parasites, if apparent

Members of the family Ascoviridae, in particular members of the genus Ascovirus, can have broad host ranges among the larvae of lepidopteran species, and the fat body tissue is a major site of replication for most species (Federici and Govindarajan 1990). The above characters are therefore used in combination to distinguish existing and new ascovirus species from one another. Hybridization studies have proven particularly useful, and when combined with RFLPs and phylogenetics can also be used to distinguish variants within a species. For example, SfAV-1a DNA does not hybridize with HvAV-3a or TnAV-2a DNAs under conditions of low stringency. TnAV-2a DNA hybridizes to some extent with HvAV-3a DNA, but not as strongly as it does with homologous DNA. In addition, TnAV-2a replicates in a range of larval tissues including the fat body, tracheal matrix and epidermis, but SfAV-1a and HvAV-3a appear to replicate, respectively, only or primarily in the fat body tissue of most hosts. SfAV-1a virions are bacilliform and are occluded in vesiculate occlusion bodies, whereas TnAV-2a virions are allantoid and are not occluded in occlusion bodies. HvAV-3a virions vary from allantoid to bacilliform, and are not occluded in occlusion bodies.

When the genome of a new isolate cross-hybridizes with that of an existing species member, RFLPs can be used to distinguish variants. Numerous ascovirus isolates, for example, have been obtained from larvae of different noctuid species, including Heliothis virescens, Helicoverpa zea, Autographa precationis and Spodoptera exigua in the United States, as well as from Helicoverpa and Spodoptera species in Australia, China and Indonesia. The DNA of many of these isolates shows strong reciprocal hybridization with HvAV-3a DNA under conditions of high stringency. RFLP profiles of these isolates, however, often show variations from HvAV-3a that range from minor to major. Because these isolates cross-hybridize strongly with HvAV-3a, they are considered variants of this viral species. Moreover, experimentally these isolates have been shown to have host ranges that overlap with HvAV-3a, providing additional evidence that they are variants of the same species. A similar situation occurs with isolates of TnAV-2a and TnAV-2b.

Member species

Species Virus name(s) Exemplar isolate Exemplar accession number Exemplar RefSeq number Available sequence Other isolates Other isolate accession numbers Virus abbreviation Isolate abbreviation
Heliothis virescens ascovirus 3a Heliothis virescens ascovirus 3a EF133465 NC_009233 Complete genome HvAV-3a
Heliothis virescens ascovirus 3a Heliothis virescens ascovirus 3f LD135790 KJ755191 HvAV-3f
Heliothis virescens ascovirus 3a Heliothis virescens ascovirus 3g 5a JX491653 HvAV-3g
Spodoptera frugiperda ascovirus 1a Spodoptera frugiperda ascovirus 1a AM398843 NC_008361 Complete genome SfAV-1a
Trichoplusia ni ascovirus 2a Trichoplusia ni ascovirus 2a AY197700; AJ279826 NC_043216; NC_042217 Partial genome TnAV-2a
Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.
Download a GenBank/EMBL query to obtain sequences listed in the table here.

Related, unclassified viruses

Virus name

Accession number

Virus abbreviation

Trichoplusia ni ascovirus 6a

(formerly Trichoplusia ni ascovirus 2c)

DQ517337

TnAV-6a

Virus names and virus abbreviations are not official ICTV designations.
Download a GenBank/EMBL query to obtain sequences listed in the table here.

Genus: Toursvirus

Distinguishing features

Currently, there is only one species within this genus, Diadromous pulchellus toursvirus. The single known member of this species, Diadromous puchellus toursvirus (DpTV) is transmitted by the parasitoid wasp Diadromous pulchellus, which typically parasitizes pupae of the lepidopteran family Yponomeutidae.

Virion

Morphology

Virions of Toursvirus are flattened rice-grain shape, and fragile relative to members of the genus Ascovirus. Virions are typically 220 nm long and 150 nm wide.

Nucleic acid

Genome consists of a circular dsDNA of about 119 kbp with a GC% of 49.7 encoding 119 putative genes. The genome of DpTV is the smallest within the family Ascoviridae.

Proteins

Eleven virion proteins are shared with members of the genus Ascovirus (Bigot et al., 2009).

Genome organization and replication

The genome of the only member of this genus, DpTV (Bigot et al., 2009) has been sequenced. Replication is largely similar to members of the genus Ascovirus.

Biology

Host range

Similar to ascoviruses, toursvirus DpTV, is transmitted by a parasitoid wasp, Diadromus pulchellus. DpTV infection has mainly been found in the pupae of members of the lepidopteran family of Yponomeutidae. The virus also has a limited replication in the ovaries of the female wasp and is vertically transmitted as extrachromosomal DNA. Compared to the lepidopteran host, replication of DpTV in the parasitoid wasp is very limited (Bigot et al., 1997).

Species demarcation criteria

 Not applicable. 

Member species

Species Virus name(s) Exemplar isolate Exemplar accession number Exemplar RefSeq number Available sequence Other isolates Other isolate accession numbers Virus abbreviation Isolate abbreviation
Diadromus pulchellus toursvirus Diadromus pulchellus toursvirus CU469068 NC_011335 Complete genome DpTV
Virus names, the choice of exemplar isolates, and virus abbreviations, are not official ICTV designations.
Download a GenBank/EMBL query to obtain sequences listed in the table here.

Authors: Ascoviridae

Sassan Asgari*
Ascoviridae Study Group Chair
School of Biological Sciences
The University of Queensland
Brisbane QLD 4072
Australia
Tel: 617-33652043
E-mail: s.asgari@uq.edu.au

Dennis K. Bideshi
California Baptist University
Department of Natural and Mathematical Sciences
8432 Magnolia Avenue
Riverside, CA 92504
USA
Tel: 951-343-4397
E-mail: dbideshi@calbaptist.edu

Yves Bigot
UMR INRA-CNRS 7247, PRC
Centre INRA de Nouzilly
37380 Nouzilly
France
Tel: 33-0-247427566
E-mail: yves.bigot@inra.fr

Brian A. Federici
Department of Entomology
Department of Interdepartmental Graduate Programs in Microbiology and Cell, Molecular and Developmental Biology
University of California
Riverside, CA 92521
USA
Tel: 951-827-5006
E-mail: brian.federici@ucr.edu

Xiao-Wen Cheng
Department of Microbiology
32 Pearson Hall
Miami University
Oxford, OH 45056
USA
Tel: (513) 529-5429
E-mail: chengx@MiamiOH.edu

* to whom correspondence should be addressed

The chapter in the Ninth ICTV Report, which served as the template for this chapter, was contributed by Bigot, Y., Asgari, S., Bideshi, D.K., Cheng X.W., Federici, B.A. and Renault, S.


Resources: Ascoviridae

Sequence alignments and tree files:

Figure 2.Ascoviridae:

Tree file (nexus format)

Alignment file (fasta format)


References: Ascoviridae

Asgari, S., Davis, J., Wood, D., Wilson, P. & McGrath, A. (2007). Sequence and organization of the Heliothis virescens ascovirus genome. J Gen Virol 88, 1120-1132. [PubMed]

Bideshi, D. K., Bigot, Y., Federici, B. A. & & Spears, T. (2010). Ascoviruses. In Insect Virology, pp. 3-34. Edited by S. Asgari & K. N. Johnson. Norfolk, UK: Caister Academic Press.

Bideshi, D. K., Demattei, M. V., Rouleux-Bonnin, F., Stasiak, K., Tan, Y., Bigot, S., Bigot, Y. & Federici, B. A. (2006). Genomic sequence of Spodoptera frugiperda Ascovirus 1a, an enveloped, double-stranded DNA insect virus that manipulates apoptosis for viral reproduction. J Virol 80, 11791-11805. [PubMed]

Bideshi, D. K., Tan, Y., Bigot, Y. & Federici, B. A. (2005). A viral caspase contributes to modified apoptosis for virus transmission. Genes Dev 19, 1416-1421. [PubMed]

Bigot, Y., Rabouille, A., Doury, G., Sizaret, P. Y., Delbost, F., Hamelin, M. H. & Periquet, G. (1997a). Biological and molecular features of the relationships between Diadromus pulchellus ascovirus, a parasitoid hymenopteran wasp (Diadromus pulchellus) and its lepidopteran host, Acrolepiopsis assectella. J Gen Virol 78 ( Pt 5), 1149-1163. [PubMed]

Bigot, Y., Rabouille, A., Sizaret, P. Y., Hamelin, M. H. & Periquet, G. (1997b). Particle and genomic characteristics of a new member of the Ascoviridae: Diadromus pulchellus ascovirus. J Gen Virol 78 ( Pt 5), 1139-1147. [PubMed]

Bigot, Y., Renault, S., Nicolas, J., Moundras, C., Demattei, M. V., Samain, S., Bideshi, D. K. & Federici, B. A. (2009). Symbiotic virus at the evolutionary intersection of three types of large DNA viruses; iridoviruses, ascoviruses, and ichnoviruses. PloS one 4, e6397. [PubMed]

Federici, B. A. (1983). Enveloped double-stranded DNA insect virus with novel structure and cytopathology. Proceedings of the National Academy of Sciences of the United States of America 80, 7664-7668. [PubMed]

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Furlong, M. J. & Asgari, S. (2010). Effects of an ascovirus (HvAV-3e) on diamondback moth, Plutella xylostella, and evidence for virus transmission by a larval parasitoid. J Invertebr Pathol 103, 89-95. [PubMed]

Hamm, J. J., Pair, S. D. & Marti, O. G. (1986). Incidence and host range of a new ascovirus isolated from fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae). Fla Entomol 69, 524-541.

Huang, G. H., Wang, Y. S., Wang, X., Garretson, T. A., Dai, L. Y., Zhang, C. X. & Cheng, X. W. (2012). Genomic sequence of Heliothis virescens ascovirus 3g isolated from Spodoptera exigua. J Virol 86, 12467-12468. [PubMed]

Piegu, B., Asgari, S., Bideshi, D., Federici, B. A. & Bigot, Y. (2015). Evolutionary relationships of iridoviruses and divergence of ascoviruses from invertebrate iridoviruses in the superfamily Megavirales. Mol Phylogenet Evol 84, 44-52. [PubMed]

Smede, M., Furlong, M. J. & Asgari, S. (2008). Effects of Heliothis virescens ascovirus (HvAV-3e) on a novel host, Crocidolomia pavonana (Lepidoptera: Crambidae). J Invertebr Pathol 99, 281-285. [PubMed]

Tan, Y., Bideshi, D. K., Johnson, J. J., Bigot, Y. & Federici, B. A. (2009). Proteomic analysis of the Spodoptera frugiperda ascovirus 1a virion reveals 21 proteins. J Gen Virol 90, 359-365. [PubMed]

Tillman, P. G., Styer, E. L. & Hamm, J. J. (2004). Transmission of ascovirus from Heliothis virescens (Lepidoptera: Noctuidae) by three parasitoids and effects of virus on survival of parasitoid Cardiochiles nigriceps (Hymenoptera: Braconidae). Environ Entomol 33, 633-643.

Wang, L., Xue, J., Seaborn, C. P., Arif, B. M. & Cheng, X. W. (2006). Sequence and organization of the Trichoplusia ni ascovirus 2c (Ascoviridae) genome. Virology 354, 167-177. [PubMed]

Wei, Y. L., Hu, J., Li, S. J., Chen, Z. S., Cheng, X. W. & Huang, G. H. (2014). Genome sequence and organization analysis of Heliothis virescens ascovirus 3f isolated from a Helicoverpa zea larva. J Invertebr Pathol 122, 40-43. [PubMed]


Citation: Ascoviridae

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:

Asgari, S., Bideshi, D.K., Bigot, Y., Federici, B.A., Cheng, X. and ICTV Report Consortium, 2017, ICTV Virus Taxonomy Profile: AscoviridaeJournal of General Virology, 98:45.