Identification of mixed phytoplasma infection in Cistus ladanifer

Molecular identification of phytoplasmas infecting wild Cistus ladanifer shrubs in Portugal was carried out. Symptoms on tested shrubs were witches’ broom and sparse foliage or small leaf size. Amplification of ribosomal genes by nested-PCR and restriction fragment length polymorphism analyses with informative endonucleases allow to detect and identify phytoplasmas in subgroups 16SrI-B and 16SrXII-A in mixed infection. Direct sequencing of selected amplicons confirmed the RFLP identification for the 16SrXII-A phytoplasmas for which the two sequenced amplicons were 99-100% homologous to ‘Candidatus Phytoplasma solani’ sequences available in GenBank. The is the first report of phytoplasmas in labdanum and represents the further demonstration of the ability of these prokaryotes to infect diverse wild host species such as Cistaceae in the Malvales order.