Identification and molecular characterization of the phytoplasma associated with leaf stunting and yellowing disease in Razavi and North Khorasan provinces

In 2017, leaf stunting and yellowing were observed on twigs and branches of stone fruit trees in production regions in Razavi and North Khorasan provinces of Iran. For diagnosis of disease and identification of the causal agent, symptomatic leaf samples were collected in these orchards and were carried to the laboratory. The disease agent was successfully transmitted by grafting from naturally symptomatic samples to peach (Prunus persica) seedlings. Total DNA was extracted from plant samples and indexed by nested PCR using phytoplasma generic primers, P1/P7 and R16F2n/R2. PCR products were sequenced and the nucleotide sequences were compared with those of other phytoplasmas in GenBank and analyzed by virtual restriction fragment length polymorphism (RFLP). The phytoplasmas associated with leaf stunting and yellowing disease in Razavi and North Khorasan provinces were identified as members of the 16SrIX group or Pigeon pea witches broom (Candidatus Phytoplasma phoenicium). This is the first report of leaf stunting and yellowing disease and characterization of associated phytoplasma in these regions.