Detection and identification of the phytoplasma associated with pear decline disease and the pear psylla, Cacopsylla pyricola in Fars and Khorasan-e-Razavi provinces*

During 2007-2012 surveys, pear decline (PD) symptoms was observed in different pear orchards in Mashhad andChenaran (Khorasan-e-Razavi province), and 11 areas in Fars province. In nested PCR assays using P1/P7 primer pair in the first round and R16F2n/R16R2 and fO1/rO1 primer pairs in the second round, expected fragments of 1250 and 1050 bp, respectively, were amplified from symptomatic naturally infected pear trees, pear psyllid (Cacopsylla pyricola) insects collected on PD affected trees and experimentally inoculated plants. Real and virtual RFLP analyses showed that phytoplasmas detected in naturally decline affected pear trees, inoculated plants and psyllid insects were identical and belonged to 'Candidatus Phytoplasma pyri'. Phylogenetic analysis also confirmed that the detected phytoplasmas are closely related to 'Ca. Phytoplasma pyri'. As representatives of PD phytoplasmas detected in Fars and Khorasan-e-Razavi provinces, respectively, pear decline agents from Bajgah and National orchard were transmitted from PD affected trees to pear and quince young trees by grafting and to periwinkle via dodder inoculation. This is the first report of association of 'Ca. Phytoplasma pyri' with PD disease and psylla insects in Khorasan-e-Razavi and some areas in Fars province, Iran.