Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 3/2/2009
Publication Date: 3/4/2010
Citation: Ravelonandro, M., Scorza, R. 2010. Silencing in genetically engineered Prunus domestica provides durable and safe resistance to Plum pox virus (sharka disease). Acta Horticulturae. Interpretive Summary:
Technical Abstract: Originally identified in Bulgaria in 1915, Plum pox virus (PPV) is the most damaging virus of stone fruit trees including apricot, plum, peach, and cherry. PPV steadily spread throughout Europe over the years since its discovery, and at the turn of the century (1999-2000), it reached North America (USA and Canada). While many strategies to control the spread of PPV have been undertaken over the decades and many studies have contributed to the characterization of the virus isolates, there has been relatively little progress in the development of resistant varieties. With the paucity of natural resistance, transgenic technology based on the engineering of the virus capsid gene was investigated as a useful source of resistance. This work identified the C5 plum clone as highly resistant to PPV infection. These findings were supported by detailed molecular studies indicating that post-transcriptional gene silencing (PTGS) is the resistance mechanism with resistance being mediated through the production of small interfering RNA (siRNA). The durability of PPV resistance in C5 (named 'HoneySweet') is reflected through more than 10 years of field tests. In total, almost 16 years of research with 'Honeysweet' have demonstrated that this clone and the resistance mechanism that it represents is: 1) an important tool to demonstrate the successful deployment of biotechnology against a quarantine pest, 2) a safe product of biotechnology, and 3) a useful strategy for avoiding the use of pesticides to control natural aphid vectors of PPV. The deregulation of ‘Honeysweet’ in the USA by USDA/APHIS (Federal Register Doc. E7-13649, July 12, 2007) corroborates the utility of these findings.