|Souza, Junior - EMBRACA GRB, BRAZIL|
|Nickel, Osmar - EMPRABA G&W, BRAZIL|
Submitted to: Brazilian Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 27, 2004
Publication Date: August 20, 2005
Citation: Souza, J., Nickel, O., Gonsalves, D. 2005. Development of virus resistant transgenic transgenic papayas expressing the coat protein from a Brazilian isolate of papaya ringspot virus (prsv). Fitopatologia Brasileira. 30:357-365. Interpretive Summary: Transgenic papaya resistant to papaya ringspot virus (PRSV) has effectively controlled papaya ringspot virus in Hawaii following its commercialization in 1998. A technology transfer program to develop PRSV-resistant transgenic papaya for Brazil was initiated with Gonsalves’ laboratory and EMBRAPA of Brazil in the early 1990s. Transgenic papaya resistant to PRSV were successfully developed in Gonsalves’ laboratory by Brazilian scientists and transferred to EMBRAPA. Selected lines have been characterized for their resistance. These transgenic papaya hold much promise to control the severe PRSV problem in Brazil.
Technical Abstract: Translatable and untranslatable versions of the coat protein (cp) gene of a Papaya ringspot virus (PRSV) isolate collected in the State of Bahia, Brazil, were engineered for expression in Sunrise and Sunset Solo varieties of Carica papaya L. The biolistic system was used to transform secondary somatic embryo cultures derived from immature zygotic embryos. Fifty four transgenic lines, 26 containing translatable and 28 containing untranslatable gene versions, were regenerated; giving approximately 2.7% transformation efficiency, when considering number of transgenic lines obtained per number of immature zygotic embryo excised. Inoculation of cloned R0 plants with PRSV BR, PRSV HA or PRSV TH, revealed lines with mono-, double- and even triple-resistance. After molecular analysis and a preliminary agronomic evaluation done in a field trial in Brasilia, DF, Brazil 13 R1 and R2 populations were incorporated into the papaya-breeding program at Embrapa Cassava and Tropical Fruits, in Cruz das Almas, Bahia, Brazil.