Update on the development of virus-resistant papaya: Virus-resistant transgenic papaya for people in rural communities of Thailand
Abstract:Papaya (Carica papaya L.) is one of the most important and preferred crops in rural communities in Thailand. Papaya ringspot virus (PRSV) is a serious disease of papaya throughout Thailand. Efforts to control the virus by various methods either have not been successful or have not resulted in sustainable control. In 1995, collaborative research by the Department of Agriculture of Thailand and Cornell University to develop transgenic papaya resistant to PRSV was initiated. Two local Thai cultivars were transformed by microprojectile bombardment with the use of a nontranslatable coat protein gene of PRSV from Khon Kaen. Numerous kanamycin-resistant plants were regenerated and were inoculated with the PRSV Khon Kaen isolate for selection of resistant lines.
Since 1997, promising R0 transgenic lines have been transferred to the research station at Thapra for subsequent screenhouse tests and selection of the most PRSV-resistant lines. In selection set 1, three R3 lines initially derived from Khaknuan papaya showed excellent resistance to PRSV (97% to 100%) and had a yield of fruit 70 times higher than nontransgenic Khaknuan papaya. In selection set 2, one R3 line initially derived from Khakdam papaya showed 100% resistance.
Safety assessments of these transgenic papayas have so far found no impact on the surrounding ecology. No natural crossing between transgenic and nonmodified papaya was observed beyond a distance of 10 m from the test plots. Analysis of the nutritional composition found no differences in nutrient levels in comparison with the nonmodified counterparts. Molecular characterization by Southern blotting revealed three copies of the transgene presented; however, no coat protein product was expressed. Data on additional topics, such as the effects of feeding the transgenic papaya to rats and the stability of the gene inserts, are currently being gathered.
Document Type: Research Article
Publication date: December 1, 2005
Established in 1978, the Food and Nutrition Bulletin (FNB) is a peer-reviewed journal published quarterly by the Nevin Scrimshaw International Nutrition Foundation.
The focus of the journal is to highlight original scientific articles on nutrition research, policy analyses, and state-of-the-art summaries relating to multidisciplinary efforts to alleviate the problems of hunger and malnutrition in the developing world.
Food and Nutrition Bulletin's 2012 Impact Factor: 2.106
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