Genus Macluravirus

Type Species	Maclura mosaic virus	(MacMV)

Virion Properties

Virions are flexuous filaments mostly 650-675  nm 13-16  nm. Virion S_20w is 155-158S; density in CsCl is 1.31-1.33  g/cm³. Virions contain one molecule of linear positive sense, ssRNA. RNA is approximately 8.0  kb. Macluraviruses have a single CP species of Mr 33-34 10³. No lipid or carbohydrate are reported.

Genome Organization and Replication

The amino acid sequences of macluravirus CPs show limited (14-23%) homology with CP sequences of some aphid-transmitted potyviruses. Macluraviruses show significant amino acid sequence homology in portions of the replicase protein with viruses in other genera of the family Potyviridae. Characteristic cytoplasmic cylindrical (“pinwheel”) inclusions are present in infected cells. The macluraviruses presumably have a genome organization and replication strategy typical of viruses in the family Potyviridae.

Antigenic Properties

Moderately immunogenic. No serological relationships to members of the genus Potyvirus have been found except for a weak reactions between Maclura mosaic virus (MacMV) and Narcissus latent virus (NLV) and MacMV and Bean yellow mosaic virus (BYMV). The amino acid sequence identities between MacMV and NLV CP and NIb protein are 53% and 76%, respectively.

Biological Properties

Host Range

Both MacMV and NLV have a narrow host range, infecting species in up to 9 host families. MacMV has only been reported from the former Yugoslavia while NLV is likely to occur wherever narcissus, gladiolus and bulbous iris are grown.

Transmission

The viruses are transmitted by aphids in a non-persistent manner and are transmissible experimentally by mechanical inoculation.

List of Species Demarcating Criteria in the Genus

	Genome sequence relatedness. CP amino acid sequence identity less than approximately 80%, Nucleotide sequence identity less than 85% over whole genome, Different polyprotein cleavage sites.
	Natural host range. Host range may be related to species but usually not helpful in identifying species. May delineate strains.
	Pathogenicity and cytopathology. Different inclusion body morphology, Lack of cross-protection, Seed transmissibility, or lack thereof, Some aspects of host reaction may be useful (e.g., resistance genes, different responses in key host species).
	Mode of transmission. Different primary vectors, but vector species not of use in identification to virus species.
	Antigenic properties. Serological differences.

List of Species in the Genus

Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names and assigned abbreviations ( ) are:

Species in the Genus

Maclura mosaic virus	(MacMV)
Narcissus latent virus	(NLV)

Tentative Species in the Genus

None reported.