Genetic Transformation of “Solo” and Native Type Papaya for Resistance to Papaya Ringspot Potyvirus
UVG, ICADA, ICTA (Guatemala); University of Georgia, Purdue University (US)
M. Palmieri, J. M. Seijas, L. Lopez, (UVG); G. Sanchez, L. Calderon (ICADA); D. Dardon (ICTA); W. Parrott, M. Deom (U. of Georgia); S. Weller (Purdue University)
Papayas represent a major potential export crop for Guatemala to the US, especially the export of Hawaiian-type “Solo” papayas which, when eaten fresh, have high nutritional value. Papaya production is increasing each year in Guatemala, especially in the southern, oriental and northern regions with new plantings of at least 1,000 ha occurring each year. One of the main threats to all papaya production in Guatemala is infection by the papaya ringspot potyvirus (PRV-p) which drastically reduces productivity and threatens to eliminate the entire system because fruits from infected trees are rendered unmarketable and often trees eventually die. This project sought to develop PRV-p resistant “solo” and local cultivar papaya plants, using a coat protein (CP)-mediated resistance gene that is introduced into somatic embryos via Agrobacterium tumefasciens to increase production of the papaya.
1. Differentiate transformed embryos, confirm the presence of the CP gene and its level of expression and compare their growth and development to regenerated embryo sand embryos transformed with a hygromycyn gene. 2. Continue greenhouse pollination studies between transformed and non-transformed papaya and investigate levels of resistance to the ring spot virus of progeny.
This transformation project for papaya has generated great expectation in Central America, because it is the first of its kind in Guatemala. If the putatively transformed papayas express the gene for ring spot resistance satisfactorily and the phenotypic characteristics are adequate, the transgenic germplasm could become thefounding block of the papaya exporting industry in the future.