ARS | Publication request: Inheritance of RNA silencing and PPV resistance in transgenic progeny of 'HoneySweet' plum

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 19, 2010
Publication Date: September 5, 2010
Citation: Ravelonandro, M., Scorza, R., Briard, P., Lafargue, B., Renaud, R. 2010. Inheritance of RNA silencing and PPV resistance in transgenic progeny of 'HoneySweet' plum. International Symposium on Plum Pox Virus. p. 29.

Technical Abstract: Plum pox virus (PPV) is one of the major diseases affecting the stone fruit industry. For this reason, the production of PPV resistant stone fruit trees is an important objective for developing sustainable agricultural systems. Over the last 10 years of field trials, 'HoneySweet' plum has displayed a stable and durable resistance to PPV infection. Based on these observations, 'HoneySweet' was cross-hybridized with P. spinosa rootstock and two French cultivars of P. domestica "Prunier d'Ente 303" and "Quetsches 2906". The virus coat protein transgene was transferred to the progeny in these hybridizations in a Mendelian inheritance pattern as a dominant trait, producing an average ratio of 46% transgenic hybrid trees. To evaluate the potential PPV resistance of these hybrids, the inheritance of the intact resistance transgene from 'HoneySweet' was molecularly verified through PCR and DNA-blotting. The similarity shown in these tests between 'HoneySweet' and its transgenic progeny indicated the stable integration of the 'HoneySweet' transgene traits in these plants. Applying the same technology developed for PPV challenge tests of 'HoneySweet', we demonstrated that the hybrid plums were PPV resistant like the 'HoneySweet' parent. We also showed that in the hybrids, like 'HoneySweet', the capsid-gene was methylated and the siRNA doublet was detected. Considering that the production of elite plum cultivars via the Agrobacterium system could be hampered by the difficulty in transformation of vegetative organs such as leaves, we demonstrate here an alternative strategy for setting up an agricultural biotechnology program that includes seed-based transformation and conventional hybridization to develop new PPV resistant varieties.