Location: Tropical Crops and Germplasm ResearchTitle: Diversity of Papaya ringspot virus isolates in Puerto Rico
|Zambrana-echevarria, C. - University Of Puerto Rico|
|De Jesus-kim, L. - University Of Puerto Rico|
|Marquez-karry, R.g. - University Of Puerto Rico|
|Siritunga, D. - University Of Puerto Rico|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2016
Publication Date: N/A
Interpretive Summary: Papaya ringspot virus is the most limiting factor in papaya production worldwide. Currently there are no conventional methods for the management of this disease, but transgenic papaya that are resistant to the virus have been very successful in Hawaii. However, the genetic diversity of this virus means that transgenic papaya that are effective in Hawaii are not resistant to strains of the virus in other parts of the world. We explore the genetic diversity of Papaya ringspot virus in Puerto Rico and compare it to isolates from other parts of the world. We find that the virus strains isolated from Puerto Rico are more closely related to those in the USA followed by strains in Australia and Central and South America. This suggests that PRSV from Puerto Rico and the isolates from these locations have a common origin thought to be from a Mexican population. This will be important in designing transgenic papaya that is resistant to the virus in the region. It remains to be seen if transgenic papaya designed for the virus population in Florida will work in Puerto Rico or Central and South America, but our study suggests this is a possibility.
Technical Abstract: Papaya ringspot virus (PRSV) devastates papaya production worldwide. In Puerto Rico, papaya fields can be completely infected with PRSV within a year of planting. Information about the diversity of the Puerto Rican PRSV population is relevant in order to establish a control strategy in the island. The coat protein (CP) gene of PRSV was sequenced from 62 isolates from different regions in Puerto Rico. The viral population of PRSV in Puerto Rico has 4% nucleotide and 5% amino acid diversity. Analysis of the CP amino acid sequence showed a variable N-terminal region with a conserved aphid transmission motif (DAG) and a variable EK repeat region. The core and C-terminal region were found to be conserved. In the phylogenetic analysis, Puerto Rican isolates grouped independent of their geographical origin, with the exception of Southern isolates that formed two separate subgroups and were the most divergent. CP gene sequences from the Puerto Rican isolates when compared to sequences from other countries showed least genetic distance with isolates from the USA followed by Australian and other countries in the Americas. This suggests that PRSV from Puerto Rico and the isolates from these locations have a common origin thought to be from a Mexican population.