Papaya mosaic virus (PapMV) is a plant pathogenic virus in the genus Potexvirus and the family Alphaflexiviridae. PapMV is a filamentous, flexuous rod, 530 nm in length.[1]
The virus is a monopartite strand of positive-sense, single-stranded RNA surrounded by a capsid made for a single viral encoded protein. The genome has been completely sequenced[2] and is 6656 nucleotides long. It is transmitted by mechanical inoculation. No insect vector is involved and it is not transmitted in seeds.
Mature virions form banded inclusions[3] that can be seen in leaf strips of infected plants[4] [5] when stained with either the Orange-Green protein stain or the Azure A nucleic acid stain.[6] [7]
Its principal host is papaya (Carica papaya), although in host range studies, PapMV was able to infect a few other plants including snapdragons (Antirrhinum majus). It is also reported to naturally infect Ullucus tuberosus.
PapMV was first reported in papaya in 1962[8] together with another virus that became known as Papaya ringspot virus (PRSV), a potyvirus. The two viruses were differentiated in 1965 and 1967 using particle lengths, serology, host range,[9] inclusions, and aphid transmissibility.[10]
PapMV causes mild mosaic symptoms on papaya leaves and stunting of the plant.[11] It is known to occur in South America (Bolivia, Peru, and Venezuela) and the USA.