Molecular characterization of phytoplasma associated with Echinops witches' broom disease

Echinops spinosissimus plants in Al-Sharqiya region were found having excessive leaf and shoot growth and stunting reminiscent of phytoplasma symptoms. Polymerase chain reaction (PCR) was used to amplify 16S ribosomal gene of phytoplasma using universal primers P1/P7. The PCR amplifications from all infected plants yielded a product of 1.8 kb by P1/P7. Restriction fragment length polymorphism showed that E. spinosissimus phytoplasma is different from alfalfa and lime witches' broom phytoplasmas from Oman. Sequence homology results on BLAST and phylogenetic analysis of 16S rRNA gene sequences confirms that the closest phytoplasma relatives of Echinops witches' broom phytoplasma are members of pigeon pea witches' broom phytoplasma ribosomal group (I 6SrIX) that share more then 98% 16S rDNA sequence similarity.