Transgenic virus-resistant papaya: current status and future trends
Gustavo Fermin, Paula Tennant and Sudeshna Mazumdar-Leighton
from: Genes, Genetics and Transgenics for Virus Resistance in Plants (Edited by: Basavaprabhu L. Patil). Caister Academic Press, U.K. (2018) Pages: 141-158.
Viruses pose a major threat to worldwide production of papaya. Transgenic papaya varieties 'Rainbow' and 'SunUp' developed in the United States have provided durable resistance against local strains of Papaya ringspot virus (PRSV). Post-transcriptional gene silencing (PTGS) which exploits sequence homology between a transgene and the corresponding region of the invading viral genome has been used to successfully obtain PRSV-resistant plants in South America, the Caribbean, Asia, and Australia. Many of these transgenic lines await government and/or public approval prior to commercialization. This review re-emphasizes the success of Hawaiian PRSV-resistant transgenic papayas for sustainable virus resistance in the field, along with the availability of a proven transgenic toolkit. However emergence of new PRSV strains and mixed infections with viruses like Papaya leaf distortion mosaic virus and Papaya mosaic virus pose new challenges for future adoption of transgenic virus-resistant plants. In addition to PRSV, geminiviruses causing papaya leaf curl disease in Asia, Papaya meleira virus (and Papaya virus Q) in Brazil and Mexico are important targets. There is need to monitor field-level diversity and evolution of viruses against the backdrop of transgenic technologies available for next generation virus-resistant papaya benefitting farmers worldwide read more ...