Molecular detection of phytoplasmas infecting date palm in Saudi Arabia and Jordan

Date palm is one of the most important cash crops in Saudi Arabia and Jordan. Symptoms of mild leaf stunting, yellow streaking and a reduction in fruit and stalk size had been observed in date palm orchards in both countries. In Jordan a total of 262 healthy and symptomatic samples were collected from different date palm cultivars, weeds growing under date palm trees and other different plant species possible phytoplasma hosts growing in the orchards in addition to leafhoppers, while 567 leaf samples were collected from Saudi Arabia. Nested PCR was performed using phytoplasma P1/P7 and R16F2n/R2 primer pairs. BLAST analysis of the obtained sequences of samples from Jordan revealed over 98% sequence identity with different reference phytoplasma strains deposited in the GenBank and 98–100% sequence identity with ‘Candidatus Phytoplasma ulmi’-related strains. A 16SrII phytoplasma, ‘Candidatus Phytoplasma aurantifolia’-related strain was identified in the samples from Saudi Arabia.