Multigene characterization of a ‘Candidatus Phytoplasma australasia’ strain associated with Roystonea regia in Oman

Florida or Cuban royal palm (Roystonea regia (Kunth) O.F. Cook) is an important ornamental plant with many uses for humans. Royal palm trees grown in Muscat, Oman, were found exhibiting leaf yellowing, leaf decay starting on the mature leaves, and leaf stunting. Trunk tissue samples were collected and analysed with nested and semi-nested PCR assays for the 16S rRNA, translation elongation factor Tu (tuf), and immunodominant membrane protein (imp) genes, in order to characterize the phytoplasma associated with the affected trees. Sequence and phylogenetic analysis of the 16S rRNA, tuf, and imp genes indicated that the phytoplasma strains detected in the trees were identical and belonged to the 16SrII-D subgroup. This is the first report of an association between ‘Candidatus Phytoplasma asutralasia’-related strain and R. regia.