Abstract
Plum pox virus (PPV) is responsible for sharka and may induce latent infections of severalmonths during which the virus is not detectable in the aerial parts of prunus plants. A previouswork has shown that early detection of PPV was feasible in the roots of latently infectedpeach seedlings and rootstocks.The objective of the current work was (i) to optimize and to compare the performance of twomolecular based tests (real-time RT-PCR and RPA) for PPV detection in prunus roots and (ii) toapply these tests for early detection of PPV in latently infected plum rootstocks (cv. Jaspi)graft-inoculated with two isolates of the PPV-D or PPV-M strains (20 plants/isolate).Experiments were carried out in a climatic chamber mimicking seasonal conditions. Threetypes of samples were analyzed: leaves before winter phase by real-time RT-PCR, roots usingboth tests, before bud break and leaves by ELISA in the spring phase to assess the efficiencyof the inoculation procedure.The optimized test showed a better detection limit. All plants tested negative before winterbut the optimized test allowed an early PPV detection in roots with 100% and 95% detectionefficiency for PPV-D and PPV-M respectively. These results demonstrate that post-winter rootanalyses could be used for early PPV detection in nurseries.