Opuntia monacantha subsp. variegata is Opuntia monacantha infected with phytoplasmas

Opuntia monacantha subsp. variegata has the same morphological features as O. monacantha infected with cactus witches’ broom (CaWB) and it is necessary to verify if it is a different botanical plant or the same subspecies infected by phytoplasmas. A nested polymerase chain reaction test using phytoplasma 16S ribosomal gene primers followed by the sequencing of the obtained amplicons was performed. Phylogeny results complemented by virtual restriction fragment length polymorphism analyses allowed to identify the detected phytoplasmas. The results showed the 100% detection of phytoplasmas in O. monacantha subsp. variegata and indicated the presence of phytoplasmas very closely related to ‘Candidatus Phytoplasma aurantifolia=citri’. These phytoplasmas are in ribosomal subgroup 16SrII-C that is the same in which phytoplasmas associated with cactus witches’ broom from other countries are enclosed. O. monacantha and Euphorbia lactae (used as negative control) did not show amplification. These results show that O. monacantha subsp. variegata is O. monacantha infected with phytoplasmas. Considering the wide popularity of the plant it is imperative to implement precautionary measures to effectively manage and contain the dissemination of the widely spread phytoplasma in the subspecies variegata that is just an infected clone of the O. monachanta species.