Title: TRANSFORMATION OF CARICA PAPAYA L. WITH VIRUS COAT PROTEIN GENES FOR STUDIES ON RESISTANCE TO PAPAYA RINGSPOT VIRUS FROM JAMAICA
Submitted to: Tropical Agriculture (Trinidad)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 13, 2002
Publication Date: May 13, 2002
Citation: Gonsalves, D. 2002. Transformation of carica papaya l. with virus coat protein genes for studies on resistance to papaya ringspot virus from jamaica. Tropical Agriculture (Trinidad). 79:105-113.
Interpretive Summary: Following the successful development of papaya ringspot virus (PRSV)-resistant transgenic papaya for Hawaii, a technology transfer program was set up between Gonsalves' laboratory at Cornell University and Jamaica to control PRSV in Jamaica by transgenic papaya. This communication reports on the successful development of PRSV-resistant transgenic papaya that was targeted for use in Jamaica. The transgenic papaya expresses the translatable or nontranslatable coat protein genes of PRSV from Jamaica. Several transgenic lines showed promising resistance during greenhouse tests at Cornell, and subsequent evaluation in Jamaica. This report represents the first development of transgenic papaya for Jamaica and lays the foundation for the practical control of PRSV in Jamaica.
Translatable and nontranslatable versions of the coat protein gene (CP) of a Papaya ringspot virus (PRSV) isolate from Jamaica were used to transform papaya embryos by microprojectile bombardment. Some 150 transgenic calli were obtained; 39 of which were regenerated and established in the greenhouse. CP was detected (75%) by polymerase chain reaction; varying levels of CP RNA transcript and expression protein were detected by Northern analysis and enzyme-linked immunosorbent assays, respectively. RO and R1 plants were challenged under greenhouse conditions with homologous PRSV isolate from which the transgene was derived and heterologous isolates from other locations across Jamaica. RO plants carrying the translatable CP were highly resistant and more resistant (78%) to inoculation with the homologous PRSV than lines transformed with the nontranslatable CP (10%). However, 15% of the latter lines exhibited a recovery phenotype whereby plants appeared to out grow systemic infection. In the following generation, R1 plants, carrying either version of the CP, exhibited strong resistance but lower levels of resistance (6 to 46%) to heterologous PRSV isolates. The results suggest that high, broad-spectrum resistance against PRSV isolates across Jamaica should be attainable in subsequent generations by conventional breeding within and between selected transgenic lines carrying translatable and nontranslatable versions of the virus CP gene.