ARS | Publication request: Reducing the harmful impacts of plum pox virus through the use of biotechnology

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: October 28, 2010
Publication Date: December 10, 2010
Citation: Kamenova, I., Scorza, R., Ravelonandro, M., Callahan, A.M., Paunovic, S., Zagrai, I., Dorokhov, D., Blume, Y. 2010. Reducing the harmful impacts of plum pox virus through the use of biotechnology. In: Golikov, A., Atanassov, A., editors. Reducing Consensus Document on Environmental Risk and Economic Assessment of Genetically Modified Crops, Case Studies: Soybean, Maize, Sugar Beet, Reducing the Harmful Impacts of Plum Pox Virus through the Use of Biotechnology. Sofia, Bulgaria: Infoprint Pleven Press. p. 127-150.

Interpretive Summary: Plum pox virus (PPV) is the most destructive virus affecting stone fruit trees (plums, apricots, peaches and cherries). PPV is an exotic disease organism that invaded the U.S. in 1999 and is the subject of eradication efforts. Nevertheless, the disease persists in a limited area of the U.S. Genetic engineering offers the promise of disease control through non-chemical means. We have developed a PPV resistant plum, 'HoneySweet', through genetic engineering. Testing this new variety, 'HoneySweet', in Europe in areas of heavy PPV infection have shown that 'HoneySweet' is highly resistant to PPV. Tests undertaken in Europe and in the U.S. have shown the high fruit quality and environmental safety of 'HoneySweet' plum. The data developed over 20 years of testing 'HoneySweet' plum show that this plum is a promising variety to protect U.S. plum production against PPV in the U.S. and to provide a resistant variety for plum growers in Europe.

Technical Abstract: The European plum (Prunus domestica L.) is a versatile and important crop, particularly in the Black Sea Region, Middle, Southeast and Western Europe, United States, Canada, Chile, Argentina and in countries across the globe. World production in 2007 was over 9 million metric tons (mt). Since the first record of Sharka disease [caused by Plum pox virus (PPV)] in the early 1900s in Bulgaria, the disease has progressively spread via infected plant materials throughout Europe where it has destroyed well over 100 million stone fruit trees. From Europe, Sharka spread to the Middle East, Asia, and North and South America. The disease has serious agronomic and political consequences due to the enormous economic losses. Measures such as quarantine and eradication of infected trees have proved to be insufficient to stop the continuous spread of PPV, and today many countries practice coexistence with the disease in spite of heavy losses in some cases. The most dramatic progress in developing resistance to PPV has involved genetic engineering of resistance. Because few PPV resistance genes have been found to naturally occur, scientists have utilized genetic engineering techniques to develop resistant plums by inserting specific genes from the PPV into the DNA of Prunus host plants. A transgenic PPV resistant plum, 'HoneySweet', has been developed. The results obtained with 'HoneySweet' plum have demonstrated that resistance to PPV is through post-transcriptional gene silencing (PTGS). The resistance has remained durable and stable for more than 10 years in field tests. 'HoneySweet' can be used as a parent in breeding programs to rapidly select new resistant types. Work with 'HoneySweet' has provided new insights into the use of PPV resistant transgenic plums and demonstrated the lack of negative environmental impacts of these plums. These studies indicate the advantages of this technology to control the spread of PPV, to significantly improve plum production in areas of PPV infection, and to help maintain the genetic diversity of plum in these areas. In order to develop a control strategy for PPV on the European continent, a program for testing and assessment of transgenic plums currently available along with the development of locally adapted PPV-resistant plums is critical.