Developing Transgenic Papaya Resistant to Ringspot Virus for the Lake Victoria Region of Africa
WASHINGTON, DC 20523
http://www.usaid.gov
Press: (202) 712-4320
Public Information: (202) 712-4810
2003-068
FOR IMMEDIATE RELEASE
June 23, 2003
Background
Papaya ringspot virus (PRSV) threatens the Lake Victoria basin papaya industry of Tanzania and Uganda where the rate of incidence ranges from 51-100%. The rapid spread of the virus by insects and lack of resistant varieties in Africa makes effective control efforts difficult. Resistant papaya has been developed by transforming papaya with the coat protein gene of PRSV isolates originating in the targeted region. Transgenic papaya saved the Hawaii papaya industry from severe PRSV damage and other transgenic papaya strains have been produced for Jamaica, Venezuela, and Thailand. By transforming and developing transgenic papaya with the coat protein gene of PRSV isolates from the area, researchers can obtain effective and timely control of PRSV in the Lake Victoria region.
Objectives
This USAID sponsored project will survey the Lake Victoria region for PRSV and collect PRSV isolates, sequence the coat protein genes of representative all PRSV isolates in the region, engineer coat protein and synthetic transgene constructs that provide resistance to PRSV and transform papaya cultivars that are grown in the region.
Activities
Map distribution of PRSV in Lake Victoria region, collect PRSV isolates and propagate the isolates in the laboratory. The coat protein genes of the PRSV isolates that are propagated in the lab will be sequenced and compared to other PRSV isolates. The coat protein genes and other synthetic genes derived from the PRSV isolates will be constructed and engineered into transformation vectors. Embryogenic cultures will be grown from immature embryos of papaya cultivars from Lake Victoria region and Hawaii, and transformed with the viral transgene constructs while potential transformants will also be selected.
Expected results
The surveys and sequencing work will provide important information on the diversity of PRSV isolates in the Lake Victoria region, and their relation to other isolates in the world. This information allows the engineering of transgenes confering resistance to PRSV, which will be transformed into papaya cultivars grown in the region, for both export and local consumption. Tissue cultures from the initial transgenic plants will be collected and tested.
The U.S. Agency for International Development has provided economic and humanitarian assistance worldwide for more than 40 years.
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