Candidatus Phytoplasma asteris and Candidatus Phytoplasma mali strains infecting sweet and sour cherry in the Czech Republic

A survey for phytoplasma diseases was conducted in a sweet and sour cherry germplasm collection and in cherry orchards within the Czech Republic during 2014-2015. Phytoplasmas were detected in 21 symptomatic trees. Multiple infections of cherry trees by diverse phytoplasmas of 16SrI and 16SrX groups and 16SrI-A, 16SrI-B, 16SrI-L, 16SrX-A subgroups were detected by restriction fragment length polymorphism (RFLP). Nevertheless, phylogenetic analysis placed subgroups 16SrI-B and 16SrI-L inseparable together onto one branch of phylogenetic tree. This is the first report of subgroups 16SrI-A and 16SrI-L in Prunus spp., and subgroup 16SrX-A in sour cherry trees. Additionally, novel RFLP profiles for 16SrI-A and 16SrI-B-related phytoplasmas were found in cherry samples. Phytoplasmas with these novel profiles belong, however, to their respective 16SrI-A or 16SrI-B phylogenetic clades.