Plum Pox Virus and Prunus spp: The Small RNA Talk

Virus susceptibility gene silencing is one of the most promising strategies aiming at the development of resistance against Plum pox virus (PPV), a high impact disease affecting Prunus species (plum, peach, apricot, cherry and almond). Different host factor genes were targeted, incl. the members of the translation initaition complex, as well as the virus sequence, sensu stricto. Hairpin constructs were developped and introduced in susceptible stone fruit trees (diploid P. salicina) as well as in Arabidopsis thaliana in order to trigger RNAi against PPV. PPV resistant Prunus and herbaceous transgenic lines were obtained, they are being used to advance our understanding of both host-PPV interaction and the RNAi mechanism. High-throughput small RNA (sRNA) sequencing of those PPV resistant lines was performed, targeting specifically molecules linked to RNAi activity (i.e., 21- to 24-nt siRNAs). This type of information is expected to improve our knowledge concerning the RNA interference process. Variations in sRNA identity and distribution in wild type P. salicina individuals and PPV resistant transgenic lines are currently under study. From these, we also expect to identify key endogenous pathways altered by virus multiplication.

On the other hand, the use of resistant individuals derived from genetic transformation of P. salicina and model plants allows for the characterization and understanding of the RNAi process caused by the hairpin construct(s). The comparison between PPV-resistant Japanese plums and model herbaceous plants (and their susceptible wild-type counterparts) already yielded different patterns of sRNA accumulation. Based on those analyses, our results will be further discussed and used to describe plant-PPV interaction in terms of these sRNA modulations.

Funding: FONDEF G09I1008, CORFO 13CTI21520-SP07, ECOS-CONICYT C09B03