Detection and multigene characterisation of a ‘Candidatus Phytoplasma prunorum’-related phytoplasma associated with witches’ broom symptoms in pineapple fruit

Pineapple samples showing witches’ broom symptoms in the leaves at the top of the fruit were analysed to verify phytoplasma presence. 16SrX group phytoplasmas were detected after nested PCR amplification with specific primers and RFLP analyses. Sequencing of 16Sr DNA allows verification that phytoplasmas from pineapple show a 99% shared identity with ‘Candidatus Phytoplasma prunorum’. Further characterisation of the phytoplasma on ace, imp and secY genes by RFLP analyses on amplicons obtained in nested PCR assays enable the differentiation of the strain infecting pineapple from those detected in fruit trees in Europe and used as reference strains. This is the first report of phytoplasmas belonging to the 16SrX-B group from a species different from pome and stone fruit worldwide.