Molecular and biological studies of Papaya ringspot virus isolates from Brazil and Cuba

Abstract

The coat protein genes of 21 Papaya ringspot virus (PRSV) isolates from Brazil and 7 isolates from Cuba were sequenced and analyzed, and the symptoms induced by the virus isolates were evaluated in papaya (Carica papaya L. cv. Solo) and squash (Cucurbita pepo L. cv. Caserta). The virus isolates were grouped in phylogenetic trees by geographic region, presenting the highest nucleotide and amino acid identities with those isolates collected in the same regions. The American and Indian isolates, from GenBank were grouped together in the tree, and the Brazilian isolates were grouped by state; the Cuban isolates from the eastern region were closer to the American isolates than to those from the central-west region. Typical mosaic symptoms, grouped according to intensity, were observed in the inoculated papaya and squash seedlings. The variability of the coat protein genes confirmed that virus control using cross-protection and transgenic plants requires the selection of region-specific virus isolates in each country.