Molecular strategies to gain resistance to Sharka viruses (PPV) in peach and apricot
The project will develop control strategies to Plum pox virus (PPV) in stone fruits. Virus containment is done by use of healthy plants, aphid vector control, eradication of infected plants and use of resistant varieties in endemic areas.
Main objectives and tools for durable resistance induction will be:
a) Characterization of potential resistance genes in apricot (crossing populations) and transfer by marker assisted breeding. BAC libraries sequencing and gene mapping (from a major QTL in chr 1) on peach and apricot reference genomes, prediction and annotation.
b) Application of gene silencing by identification of RNA sequences involved in plant-host interaction(in infected peach and apricot) and associated to resistance. Constructs will be synthesized from candidate genes or hairpin short viral sequences and they will be transformed in apricot (Vitillo) or peach (BigTop or GF677) by Agrobacterium with zygotic or somatic tissues regeneration.
c) Presence of small RNAs and transcriptome interaction in PPV-infected peach and apricot with a different susceptibility degree. Transgene and hpRNA presence in transformed rootstocks and cultivars will be detected by hybridization and RT-PCR. Selected transgenic lines will be inoculated by green grafting or chip budding. On transgenic GF677 silencing signal translocation to conventional grafted scions will be checked. On promising lines, further analysis will be performed to study resistance mechanism according EU 2001/18 Directive.