Almond witches\u2019 broom associated with \u2018Candidatus Phytoplasma phoenicium\u2019 is an economically important
disease of almond in Iran and Lebanon. During surveys of almond witches\u2019 broom in 2012\u20132015, an apricot
yellows disease was observed in Fars Province of Iran. The characteristic symptoms of the disease were leaf
yellowing, inward leaf curl, scorch of leaf margins, shortened internodes, production of rosettes at the tips of the
branches, and decline, stunting, and death of affected trees. Healthy bitter almond and apricot seedlings, grafted
with shoots from symptomatic trees, exhibited phytoplasma-type symptoms. A 16S rDNA fragment of 1,250 bp
was amplified by nested-PCR from affected trees and grafted seedlings. Nucleotide sequence identity, presence of
species-specific signature sequences, and phylogenetic analysis of 16S rDNA allowed the assignation of the phytoplasma
strains identified to the \u2018Ca. P. phoenicium\u2019. In vitro and in silico RFLP analyses of the amplified fragment
allowed affiliation of the apricot yellows phytoplasma to a molecular variant in the subgroup 16SrIX-B. Within the
population strains identified in this and previous studies, 16 genetic lineages were determined within 16S rDNA
nucleotide sequences by the combination of 19 single nucleotide polymorphisms. The apricot yellows phytoplasma
strains belong to a unique genetic lineage distinguished by the presence of three lineage-specific SNPs. This
first report of \u2018Ca. P. phoenicium\u2019 in association with apricot yellows in Iran opens new perspectives on the epidemiology
of almond witches\u2019 broom, suggesting possible adaptation of the phytoplasma to other fruit tree species
