First report of a ‘candidatus phytoplasma aurantifolia’-related strain in citrus macrophylla in Oman

Citrus macrophylla is one of the most commonly used citrus rootstocks and it was found exhibiting witches’ broom disease symptoms. Polymerase chain reaction (PCR) was used to amplify the 16S ribosomal gene of phytoplasmas with the universal primers P1/P7 as a direct PCR and R16F2n / R16R2 primers for the nested PCR. The amplifications from all the symptomatic plants yielded a product of 1.8 kb and 1.2 kb in the direct and the nested PCR, respectively. Sequence identity results from BLAST and phylogenetic analysis of the 16S rRNA gene sequences confirmed that the phytoplasma identified in C. macrophylla in Oman is a ‘Candidatus Phytoplasma aurantifolia’-related strain.