Molecular Characterization of Phytoplasmas Related to Apple Proliferation and Aster Yellows Groups Associated with Pear Decline Disease in Iran

Pear trees showing pear decline disease symptoms were observed in pear orchards in the centre and north of Iran. Detection of phytoplasmas using universal primer pair P1A/P7A followed by primer pair R16F2n/R16R2 in nested PCR confirmed association of phytoplasmas with diseased pear trees. However, PCR using group‐specific primer pairs R16(X)F1/R16(X)R1 and rp(I)F1A/rp(I)R1A showed that Iranian pear phytoplasmas are related to apple proliferation and aster yellows groups. Moreover, PCR results using primer pair ESFYf/ESFYr specific to 16SrX‐B subgroup indicated that ‘ Ca . Phytoplasma prunorum’ is associated with pear decline disease in the north of Iran. RFLP analyses using Hae III , Hha I, Hin fI , Hpa II and Rsa I restriction enzymes confirmed the PCR results. Partial 16S rRNA, imp , rp and secY genes sequence analyses approved that ‘ Ca . Phytoplasma pyri’ and ‘ Ca . Phytoplasma asteris’ cause pear decline disease in the centre of Iran, whereas ‘ Ca . Phytoplasma prunorum’ causes disease in the north of Iran. This is the first report of the association of ‘ Ca . Phytoplasma asteris’ and ‘ Ca . Phytoplasma prunorum’ with pear decline disease worldwide.