Detection and characterization of diverse phytoplasmas in ornamental and cultivated pomegranate species in Turkey

Abstract

Yellowing, leaf curling and shoot-dieback symptoms on pomegranates have been observed in Turkey in last decade, however, the association of phytoplasmas to symptoms in pomegranates has been not fully understood. In the present study, 130 cultivated and 65 ornamental pomegranate trees were sampled from three provinces (Hatay, Adana, Sanliurfa) from southern part of Turkey. Nested-PCR assay and restriction fragment length polymorphism analysis were employed to identify the phytoplasma strains detected in symptomatic and asymptomatic pomegranate trees. Among 195 tested samples, three ornamental and six cultivated pomegranates were found positive for phytoplasmas by Nested-PCR. Based on virtual RFLP analysis of 16S rDNA sequences, the strains detected in cultivated pomegranates were related to ‘Candidatus Phytoplasma asteris' (16SrI–S), ‘Ca. P. solani’ (16SrXII-A) and ‘Ca. P. mali’ (16SrX-A) whereas in the ornamental pomegranates only to ‘Ca. P. prunorum’ (16SrX-B) was detected. The association of ‘Ca. P. mali’ and ‘Ca. P. asteris’ related strains on cultivated pomegranates and as well as ‘Ca. P. prunorum’ in ornamental pomegranates have been identified for the first time worldwide. The presence of distinct phytoplasmas in pomegranates could result a high diversity of phytoplasmas within single plant species.