Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2007
Publication Date: 2/20/2008
Citation: Tripathi, S., Suzuki, J., Ferreira, S., Gonsalves, D. 2008. Papaya Ringspot Virus: Characteristics, Pathogenicity, Sequence Variability and Control. Molecular Plant Pathology. 9:269-280.
Technical Abstract: Taxonomy: Papaya ringspot virus (PRSV) is an aphid-transmitted plant virus belonging to the genus Potyvirus of the family Potyviridae with a positive sense RNA genome. PRSV isolates belong to either one of two major strains, P-type or W-type. The P-type infects both papaya and cucurbits whereas the W-type infects only cucurbits. Geographic distribution: The PRSV is found in all parts of world wherever papaya is grown. Physical properties: Virions are filamentous, nonenveloped and usually flexuous measuring 760-800 x 12 nm. Virus particles contain 94.5% protein and 5.5% nucleic acid. The protein component consists of the virus coat protein (CP) which has a molecular weight (Mr) of 36,000-36,500, although protein species of Mr 31,000-34,000 and 26,000-27,000 are also observed. Purified virions are not stable under long term storage; virus preparations stored for two months contain primarily the smaller CP forms due to proteolytic degradation. Density of the sedimenting component in purified PRSV preparations is 1.32 g cm-3 in CsCl. Genome: The PRSV genome consists of a unipartite linear single-stranded positive sense RNA of 10,326 nucleotides with a 5’ terminus genome-linked protein, VPg. Transmission: Virions are transmitted via the aphid insect vector, in a non-persistent manner. The virus-encoded amorphous inclusion protein (AI) is required for vector transmission. Virus can be transmitted by mechanical inoculation but it is not transmitted through to the seed of infected plants. Hosts: PRSV has a limited number of hosts; they belong to the families Caricaceae, Chenopodiaceae and Cucurbitaceae. Propagation hosts are: Carica papaya, Cucurbita pepo, Cucumis metuliferus cv accession 2459. Local lesion assay hosts are: Chenopodiun quinoa, Chenopodium amaranticolor. Control: Two transgenic varieties, SunUp and Rainbow, with engineered resistance to PRSV have been grown successfully to combat PRSV for commercial production in Hawaii since 1998. Virus Code: 00.057.0.01.045. Virus Accession number 57010045 Useful link: http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/57010045.htm