Distribution of the Sour Cherry Isolate of Plum Pox Virus in Infected Prunus Rootstocks

Six Prunus genotypes used as rootstocks, including two interspecific hybrids, were chip-inoculated with the sour cherry isolate of Plum pox virus (PPV-SoC) to study the ability of the virus to infect different Prunus species and determine its localization within infected trees. The symptoms were noted and their location within trees was determined by AMAPmod methodology to monitor viral infection. After 3 years, five of the six Prunus genotypes tested (GF8.1, Jaspi, F12.1, Edabriz and SL64) were infected and showed different patterns of infection. Generally, symptomatic leaves in all the infected genotypes were not consecutive on the shoots, thus resulting in a large symptomatic zone. The virus was characterized by its irregular distribution in all the infected Prunus plants. The Colt genotype could not be infected in vivo, but PPV-SoC could be transmitted by in vitro grafting. We conclude that PPV-SoC is able to systematically infect different cherry and plum rootstocks. The host range of PPV-SoC thus appears to be wider than that of conventional PPV isolates.