Complete Nucleotide Sequence and Genetic Organization of Papaya Ringspot Virus RNA

Abstract

The complete nucleotide sequence of the RNA genome of papaya ringspot virus (PRSV) was determined from four overlapping cDNA clones and by direct sequencing of viral RNA. The genomic RNA is 10326 nucleotides in length, excluding the poly(A) tract, and contains one large open reading frame that starts at nucleotide positions 86 to 88 and ends at positions 10118 to 10120, encoding a polyprotein of 3344 amino acids. The highly conserved sequence AAAUAAAANANCUCAACACAACAUA at the 5' end of the RNA of PRSV and those of the other five reported potyviruses shows 80% similarity, suggesting that this region may play a common important role for potyvirus replication. Two cleavage sites of the polyprotein were determined by amino acid sequencing of the N termini of helper component (HC-Pro, amorphous inclusion) and cylindrical inclusion (CI) proteins. Other cleavage sites were predicted by analogy with the other potyviruses. The genetic organization of PRSV is similar to that of the other potyviruses except that the first protein processed from the N terminus of the polyprotein (NT protein) has an Mr of 63K, 18K to 34K larger than those of the other potyviruses. The cleavage site for liberating the N terminus of the HCPro protein was found at the same location downstream from the consensus sequence FI(V)VRG as that reported for tobacco vein mottling virus. The NT protein of potyviruses is the most variable and may be considered important for identification of individual potyviruses. The most conserved protein ofpotyviruses appears to be the Nlb protein, the putative polymerase for the replication of the potyviral RNA. The genetic organization of PRSV RNA is tentatively proposed to be VPg-5' leader-63K NT-52K HC-Pro-46K-72K CI-6K-48K NIa-59K NIb-35K coat protein-3' noncoding region-poly(A) tract.

Sequence polymorphism in the 5'NTR and in the P1 coding region of potato virus Y genomic RNA

“…The complete nucleotide sequence of several members of the group is already known (Allison et al, 1986;Domier et al, 1986;Robaglia et al, 1989;Lain et al, 1989;Maiss et al, 1989;Teycheney et al, 1989;Johansen et al, 1991 ; * Author for correspondence. Fax +33 1 30 83 31 95. e-mail robaglia@oxygene.versailles.inra.fr Nicolas & Lalibertr, 1992;Yeh et al, 1992;Jayaram et al, 1992;Vance et al, 1992;Thole et al, 1993;Palkovics et al, 1993). A single ORF is translated into a polyprotein of more than 3000 amino acids, which is then proteolytically processed by three viral proteases into functional proteins (Carrington & Dougherty, 1987;Carrington et al, 1989;Verchot et al, 1991).…”

Recent advances in the development of transgenic papaya technology

“…In the mid-1980s, with the success in the development of genetically modified crops such as maize, cotton and soybean, the complete molecular characterization of PRSV [67] and the difficulty of obtaining resistant varieties of papaya through conventional methods of breeding, scientists from Cornell University and University of Hawaii initiated the development of PRSV-resistant papaya by genetic engineering.…”

Development of Recombinant Coat Protein Antibody Based IC-RT-PCR and Comparison of its Sensitivity with Other Immunoassays for the Detection of Papaya Ringspot Virus Isolates from India

“…PRSV, a definitive member of the genus Potyvirus of the family Potyviridae (van Regenmortel, 2000), is non-persistently transmitted by numerous species of aphids in nature and particles are flexuous filamentous rods of about 780×12 nm in size (Gonsalves and Ishii, 1980). The virions contain a positive sense, single stranded RNA genome approximately 10.3 kb in length surrounded by a coat protein (CP) consisting of a single protein subunit of molecular weight 36 kDa (Yeh et al, 1992). Based on the host range specificity, PRSV is classified into two types that cannot be distinguished by serological methods.…”