|Hily, Jean Michel|
Submitted to: Plant Cell Tissue and Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/3/2014
Publication Date: 4/17/2014
Citation: Ravelonandro, M., Scorza, R., Hily, J., Briard, P. 2014. The efficiency of RNA interference for conferring stable resistance to Plum Pox Virus. Plant Cell Tissue And Organ Culture. DOI: 10.1007/S11240-014-0487-3. Interpretive Summary: Genetic engineering offers the promise of disease control through non-chemical means. This technology could have important uses for tree fruits which are subject to a number of difficult to control disease problems including virus diseases. One of the most devastating virus diseases is plum pox virus which is an exotic disease organism that has recently invaded the U.S. We have developed plum plants that can “silence” the virus infection process. These plum plants were inoculated with plum pox virus and shown to be resistant to the virus. This work shows that we can now produce new plum pox virus resistance lines for breeding and variety release. These can protect the U.S. plum industry should plum pox virus establish itself in the U.S.
Technical Abstract: Plum transformed with an intron hairpin RNA CP (ihRNA-CP) were resistant to PPV infection through the specific process of RNA silencing involving both small interfering -RNA interfering (siRNA) and a methylated virus transgene. This recognition process specifically targeted the triggered PPV genome and led to the degradation of viral RNA in the model plant species Nicotiana benthamiana and the natural Prunus domestica host. Plums inoculated with the five major PPV strains, three widespread PPV strains (D, M and Rec), and the atypical EA strain did not allow systemic spread of PPV in greenhouse-grown transgenic ihRNA-CP plum over multiple cycles of vegetative growth and cold-induced dormancy. PPV ihRNA-CP N. benthamiana displayed an immunity reaction and also allowed for the testing of PPV-C, a strain that was unable to infect P. domestica. This stable resistance based onto the accumulation of siRNA, before, during and after PPV inoculation, can prevent PPV infection and can also act as a “curative” when PPV is inoculated through graft inoculation through a recovery reaction. Regardless of the variable strains based on geography, Prunus species hosts, epidemiology and serotypes of the CP protein and the few substitution of nucleotides at the NH2-terminus of CP, of the major five PPV strains selectedas challengers, transgenic ihRNA-CP plants provide strong evidence that the use of an intron hairpin (ih) RNA construct is an efficient strategy that specifically targets the PPV genome. Here, we provide methods and tools that demonstrate a reliable path towards developing PPV resistance suitable for protecting stone fruit orchards.