00.065. Sequiviridae - ICTVdB Index of Viruses

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Nature of Genome:
General Host Type:
Morphology:

positive-stranded ssRNA
Plants
not enveloped, isometric

Family	00.065. Sequiviridae
	Taxonomic Structure of the Family
	Family 00.065. Sequiviridae Genus 00.065.0.01. Sequivirus Genus 00.065.0.02. Waikavirus

Genus	00.065.0.01. Sequivirus
Type Species	00.065.0.01.001. Parsnip yellow fleck virus

List of Species Demarcation Criteria in the Genus

Members of the species Parsnip yellow fleck virus and the species Dandelion yellow mosaic virus are distinguished because

they do not cross-react with heterologous antibodies; PYFV can be divided into two serotypes (formerly regarded as separate species) that differ by serological differentiation index of 4 to 5,

their principal hosts belong to different families; PYFV infects umbelliferous plants (although the serotypes differ in host range) and Dandelion yellow mosaqic virus infects plants in the Compositae,

they are transmitted by different species of vector aphid; PYFV is transmitted by Cavariella spp. and DaYMV is transmitted by Aulacorthum solani and some Myzus spp.

List of Species in the Genus

The ICTVdB virus code and the viruses. Official virus species names are in italics. Tentative virus species names, alternative names ( ), isolates, strains, serotypes, subspecies, or rejected names are not italicized.

Virus codes, virus names, genome sequence accession numbers [ ] and assigned abbreviations ( ), are:

Species, their serotypes, strains and isolates

00.065.0.01.002.	Dandelion yellow mosaic virus
00.065.0.01.002.00.001.	Dandelion yellow mosaic virus		(DaYMV)
00.065.0.01.003.	Parsnip yellow fleck virus
00.065.0.01.003.00.002.	Celery yellow net virus		(CeYNV)
00.065.0.01.003.00.001.	Parsnip yellow fleck virus	[NC_003628]	(PYFV)

Tentative Species in the Genus

00.065.0.81.004.	Lettuce mottle virus
00.065.0.81.004.00.001.	Lettuce mottle virus		(LeMoV)

Genus	00.065.0.02. Waikavirus
Type Species	00.065.0.02.001. Rice tungro spherical virus

List of Species Demarcation Criteria in the Genus

Isolates belong to distinct species if:

gene products differ in as sequence; from limited comparisons values of <70% homology over the entire polyprotein and <80% between NTP-binding domains or proteinase domains or polymerase domains would suggest distinct species (the extent is not possible to define with certainty as too few sequences are at hand),

they differ serologically; at most, there is a very weak cross-reaction between RTSV and MCDV in immunoblots,

they differ in host range; RTSV infects rice and some other graminaceous hosts, MCDV infects maize and some other graminaceous hosts, but not rice and AYV infects umbelliferous (dicotyledonous) hosts,

they are transmitted by different vector species; MCDV and RTSV are transmitted by leafhoppers (Graminella spp. and Nephotettix spp. respectively) and AYV is transmitted by aphids.

List of Species in the Genus

Species, their serotypes, strains and isolates

00.065.0.02.002.	Anthriscus yellows virus
00.065.0.02.002.00.001.	Anthriscus yellows virus		(AYV)
00.065.0.02.003.	Maize chlorotic dwarf virus
00.065.0.02.003.00.001.	Maize chlorotic dwarf virus	[NC_003626]	(MCDV)
00.065.0.02.004.	Rice tungro spherical virus
00.065.0.02.004.00.001.	Rice tungro spherical virus	[NC_001632]	(RTSV)
00.065.0.02.004.00.002.	Rice tungro spherical virus - Vt6	[AB064963]	(RTSV-Vt6)

Tentative Species in the Genus

None reported.

List of Unassigned Viruses in the Family

None reported.

Similarity with other Taxa

The amino acid sequences in the conserved NTP-binding and RNA polymerase domains of the polyproteins resemble those in the polyproteins encoded by RNA of viruses in the unassigned genera Cheravirus and Sadwavirus, and in the families Comoviridae, Picornaviridae and Dicistroviridae. The number and sizes of the Us resemble those of viruses in the family Picornaviridae although the protein(s) upstream of the Us is larger than the L protein of aphthoviruses. The properties of the particles and the genomes of these viruses have sometimes prompted their description as 'plant picornaviruses'.

Derivation of Names

Sequi: sigla from latin sequi, to follow, accompany, attend (in reference to the dependent aphid transmission of PYFV).
Waika: from Japanese, describing the symptoms induced in rice by infection with RTSV alone (i.e. in the absence of Rice tungro bacilliform virus, RTBV).

References

Collated from VIIIth ICTV Report

Contributed by

Le Gall, O., Iwanami, T., Karasev, A.V., Jones, T., Lehto, K., Sanfaçon, H., Wellink, J., Wetzel, T. and Yoshikawa, N.

Cite this publication as: Index of Viruses - Sequiviridae (2006). In: ICTVdB - The Universal Virus Database, version 4. Büchen-Osmond, C (Ed), Columbia University, New York, USA. http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_index.htm

Version 4 is based on Virus Taxonomy, Classification and Nomenclature of Viruses, 8th ICTV Report of the International Committee on Taxonomy of Viruses. Fauquet, CM, Mayo, MA, Maniloff, J, Desselberger, U, and Ball, LA (EDS) (2005) Elsevier/Academic Press, pp. 1259.

Additional References

Reference List from the 8th ICTV Report
ICTVdB taxon description
ICTVdB Picture Gallery

References to sequence databases at GenBank and PubMed Central:
PubMed Central References; nucleotide sequences; complete genomes

Additional access points to virus species lists, descriptions and images on the web:

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