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00.010.0.01. Alfamovirus

Cite this publication as: ICTVdB Management (2006). 00.010.0.01. Alfamovirus. In: ICTVdB - The Universal Virus Database, version 4. Büchen-Osmond, C. (Ed), Columbia University, New York, USA

Cite this site as: ICTVdB - The Universal Virus Database, version 4. http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/

Table of Contents

Classification

This is a description of a plant virus at the genus level with data on all virus properties from morphology to genome, replication, antigenicity and biological properties.

ICTVdB Virus Code: 00.010.0.01. Virus accession number: 010001GE. Obsolete virus code: 10.0.1.; superceded accession number: 10010000.
NCBI Taxon Identifier NCBI Taxonomy ID: 12320.

Name, Synonyms and Lineage

Synonym(s): Alfalfa mosaic virus group. Virus is of the family 00.010. Bromoviridae.

Virion Properties

Morphology

Virions consist of a capsid. Virus capsid is not enveloped. Capsid is round to elongated with icosahedral symmetry (built of 30 dimers (60 subunits) under appropriate conditions. Particles found composed of 240 (B), 186 (M), 150 Tb or 132 (Ta) subunits, respectively). The capsid is quasi-isometric to bacilliform. Virus preparations contain more than one particle component. Virions consist of several nucleocapsids, capsids and segments have different lengths, but constant diameter with a length of 56 nm (B, 43 nm (M, 35 nm (Tb), or 30 nm (Ta that occurs either in bacilliform (Ta-b) or ellipsoidal (Ta-t) shape) and a width of 18 nm. The nucleocapsid is segmented.
























Electron micrograph of Alfalfa mosaic virus, Bromoviridae by Thorben Lundsgaard .

Electron microscopic preparation and references: Virus preparation contains many virions.

Physicochemical and Physical Properties

Virions have a buoyant density in CsCl of 1.381-1.385 g cm-3. There are 4 sedimenting component(s) found in purified preparations. The sedimentation coefficient is 94 S20w; of the other(s) are 66-82 S20w. Isoelectric point pH is 4.6. A260/A280 ratio is 1.7-1.8. The thermal inactivation point (TIP) is at 60-65°C. The longevity in vitro (LIV) is 1-4 days. Although the titer is dependent on the host, the decimal exponent (DEX) of the dilution end point is usually around 3-4. The infectivity is not changed by treatment with ether; retained when deproteinized with proteases, or decreased when deproteinized with proteases; retained when deproteinized with phenol or detergent.

Nucleic Acid

The Mr of the genome constitutes about 16% of the virion by weight (in all particle types). The genome is segmented; tripartite, segements are distribute among 3 particle types of different size; consists of four segments of linear positive-sense, single-stranded RNA. Minor species of non-genomic nucleic acid are also found in virions. The encapsidated nucleic acid is mainly of genomic origin, but virions may also contain subgenomic RNA, that is mRNA derived from genomic RNA-3. The complete genome is 8274 nucleotides long, or 9155 nucleotides long. The RNA-1 is fully sequenced, complete sequence is 3644 nucleotides long. RNA-2 is fully sequenced. Complete sequence is 2593 nucleotides long. RNA-3 is sequenced, but only an estimate is given, complete sequence is 2037 nucleotides long. RNA-4 is the encapsidated mRNA has been fully sequenced. Complete sequence is 881 nucleotides long. Subgenomic RNA-4 is an mRNA derived from RNA-3 negative strand template. The genome has a base ratio of 23 % guanine; 25 % adenine; 23 % cytosine; 29 % uracil. The genome has a guanine + cytosine content of 42.7 %. The genome sequence has termini with of RNA-3 has 7 cross-linked hairpin ends (at 3'-end non-coding region). Nucleotide sequences at the 3'-terminus are similar (of all four RNAs). The 5'-end of the genome has a methylated nucleotide cap; cap sequence type is m7G5'ppp5 ('Gp). The 3'-terminus has conserved nucleotide sequences; sequence has 145 nucleotides in length; in all RNA species. The 3'-terminus has no poly (A) tract. The 3'-terminus has no tRNA-like structure. The genome has no intergenic poly (A) region. The multipartite genome is divided among more than one type of particle and the segments are distributed between 3-7 different types of particles. The largest particles contain 3 types, each one molecule of RNA-1 (sedimenting component B). The medium sized particles contain each one molecule of RNA-2 (sedimenting component M). The smallest particles contain each one molecule of RNA3 (sedimenting component Tb), or two molecules of RNA-4 (sedimenting component Ta).

GenBank records for nucleotide sequences; complete genome sequences.

Proteins

The viral genome encodes structural proteins and non-structural proteins. Virions consist of 1 structural protein(s) located in the capsid.

Structural Proteins: Capsid protein coat. Capsid protein has a molecular mass of 24250 Da; is involved in viral encapsidation and involved in protein movement.

Lipids

Lipids are absent.

Genome Organization and Replication

By itself, genomic nucleic acid is not infectious; a successful infection by the virus requires the coat protein specifically associated with RNA 3'-terminal sequences for replicase recognition.

Transcription: Sub-genomic RNA is present in infected cells; encoding the coat protein.

Biological Properties

Natural Host

Domain
Viral hosts belong to the Domain Eucarya.

Domain Eucarya
Kingdom Plantae.

Kingdom Plantae
Phylum Magnoliophyta (Angiosperms, Class Magnoliopsida (Dicotyledonae).

Class Magnoliopsida (Dicotyledonae)
Subclass ROSIDAE; Order Fabales;
Family Fabaceae (~Leguminosae-Papilionoideae) Medicago sativa.

General Symptoms in Plants Symptoms are expressed in the leaf include deformation, or necrosis, or chlorosis; include deformation of leaves. Leaves with mosaic, or mottle.

Severity and Occurrence of Disease

Host: Signs and symptoms persist, or disappear soon after infection.

Transmission and Vector Relationships

Virus is transmitted by a vector. Virus is transmitted by mechanical inoculation; transmitted by grafting; not transmitted by contact between hosts; transmitted by seeds; transmitted by pollen to the seed.

Vector Transmission:
Virus is transmitted by arthropods, by insects of the order Hemiptera, family Aphididae. Virus is transmitted in a non-persistent manner.

Experimental Hosts and Symptoms

Under experimental conditions susceptibility to infection by virus is found in many families. Susceptible host species are found in the Family Amaranthaceae, Apocynaceae, Caprifoliaceae, Caryophyllaceae, Chenopodiaceae, Compositae, Cruciferae, Cucurbitaceae, Labiatae, Leguminosae-Papilionoideae, Linaceae, Malvaceae, Philadelphaceae, Phytolaccaceae, Polygonaceae, Scrophulariaceae, Solanaceae, Tetragoniaceae, Tropaeolaceae, Umbelliferae, Verbenaceae. The following species were susceptible to experimental virus infection: Abelmoschus esculentus, Ageratum conyzoides, Amaranthus caudatus, Amaranthus retroflexus, Antirrhinum majus, Apium graveolens, Apium graveolens var. rapaceum, Arachis hypogaea, Astragalus glycyphyllos, Beta vulgaris, Brassica campestris ssp. rapa, Calendula officinalis, Capsicum annuum, Capsicum frutescens, Caryopteris incana, Catharanthus roseus, Celosia argentea, Cheiranthus cheiri, Chenopodium album, Chenopodium amaranticolor, Chenopodium murale, Chenopodium quinoa, Cicer arietinum, Cichorium endiva, Coriandrum sativum, Crotalaria spectabilis, Cucumis melo, Cucumis sativus, Cucurbita pepo, Cyamopsis tetragonoloba, Daucus carota, Dianthus barbatus, Dianthus caryophyllus, Emilia sagittata, Fagopyrum esculentum, Glycine max, Gomphrena globosa, Helianthus annuus, Lablab purpureus, Lactuca sativa, Lathyrus odoratus, Lens culinaris, Linum usitatissimum, Lupinus albus, Lycopersicon esculentum, Macroptilium lathyroides, Malva parviflora, Matthiola incana, Medicago hispida, Medicago sativa, Melilotus albus, Nicotiana bigelovii, Nicotiana clevelandii, Nicotiana debneyi, Nicotiana glutinosa, Nicotiana megalosiphon, Nicotiana rustica, Nicotiana sylvestris, Nicotiana tabacum, Ocimum basilicum, Petunia x hybrida, Phaseolus lunatus, Phaseolus vulgaris, Philadelphus, Physalis floridana, Physalis peruviana, Phytolacca americana, Pisum sativum, Solanum demissum, Solanum melongena, Solanum nigrum, Solanum nodiflorum, Solanum rostratum, Solanum tuberosum, Sonchus oleraceus, Spinacia oleracea, Stellaria media, Tetragonia tetragonioides, Trifolium dubium, Trifolium hybridum, Trifolium incarnatum, Trifolium pratense, Trifolium repens, Trifolium subterraneum, Tropaeolum majus, Viburnum opulus, Vicia faba, Vigna radiata, Vigna unguiculata, Vigna unguiculata ssp. sesquipedalis , Zinnia elegans.

Experimentally infected insusceptible Hosts: Families containing insusceptible hosts: Chenopodiaceae, Compositae, Cruciferae, or Leguminosae-Caesalpinioideae, Leguminosae-Papilionoideae, Solanaceae. Species inoculated with virus that do not show signs of susceptibility: Atriplex hortensis, Brassica oleracea var. capitata, Cassia tora, Chenopodium capitatum, Chenopodium foetidum, Datura stramonium, Hyoscyamus niger, Lotus corniculatus, Nicandra physalodes, Sesbania exaltata, Verbesina encelioides, Vicia sativa, Vicia villosa.

Histopathology: Virions are found in the cytoplasm, or chloroplast.

Cytopathology: Inclusions are present in infected cells. Inclusion bodies in the host cell are found in the cytoplasm. Inclusions contain mature virions.

Geographical Distribution

The virus is probably distributed worldwide.

Taxonomic Structure of the Genus

Type species 00.010.0.01.001. Alfalfa mosaic virus .

Species in the Genus

List of Species in the Genus.

Data Sources and Contributions

The description has been compiled from data in the ICTV Report presented by Rybicki EP.

References

The following generic references are cited in the most recent ICTV Report.

PubMed References.

Images

Taxon images: • EM by Robert G. Milne. • EM by Robert G. Milne. • courtesy of A.J. Gibbs and VIDE. • EM from IACR Rothamsted. • courtesy of A.J. Gibbs and VIDE. • courtesy of A.J. Gibbs and VIDE. • courtesy of A.J. Gibbs and VIDE.



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DELTA - DEscription Language for TAxonomy developed by Dr Mike Dallwitz, Toni Paine and Eric Zurcher, CSIRO Entomology, Canberra, Australia. ICTVdB - The Universal Virus Database, developed for the International Committee on Taxonomy of Viruses by Dr Cornelia Büchen-Osmond is written in DELTA. The virus descriptions in ICTVdB are coded by, or using data from experts in the field of virology or members ICTV. The character list is the underlying code. All virus descriptions are based on the character list and natural language translations are automatically generated and formatted for display on the Web from the descriptions in DELTA-format. The description has been generated automatically from DELTA files. DELTA - DEscription Language for TAxonomy developed by Dr Mike Dallwitz, Toni Paine and Eric Zurcher, CSIRO Entomology, Canberra, Australia.

ICTVdB - The Universal Virus Database, developed for the International Committee on Taxonomy of Viruses (ICTV) by Dr Cornelia Büchen-Osmond, is written in DELTA. The virus descriptions in ICTVdB are coded by ICTV members and experts, or by the ICTVdB Management using data provided by the experts, the literature or the latest ICTV Report. The character list is the underlying code. All virus descriptions are based on the character list and natural language translations from the encoded descriptions are automatically generated and formatted for display on the Web.

Developer of the DELTA software: M. J. Dallwitz, T. Paine and E. Zurcher

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Last updated on 25 April 2006 by Cornelia Büchen-Osmond
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