Recently, peach trees showing leaf rolling, little leaf, rosetting, yellowing, bronzing of foliage and tattered and shot-holed leaves symptoms were observed in peach growing areas in the central and north-western regions of Iran. Polymerase chain reaction (PCR) and nested PCR using phytoplasma universal primer pairs P1/Tint, R16F2/R2, PA2F/R and NPA2F/R were employed to detect phytoplasmas. The nested PCR assays detected phytoplasma infections in 51% of symptomatic peach trees in the major peach production areas in East Azerbaijan, Isfahan, ChaharMahal-O-Bakhtiari and Tehran provinces. Restriction fragment length polymorphism (RFLP) analyses of 485 bp fragments amplified using primer pair NPA2F/ R in nested PCR revealed that the phytoplasmas associated with infected peaches were genetically different and they were distinct from phytoplasmas that have been associated with peach and almond witchesÕ-broom diseases in the south of Iran. Sequence analyses of partial 16S rDNA and 16S-23S rDNA intergenic spacer regions demonstrated that ÔCandidatus Phytoplasma aurantifoliaÕ, ÔCa. Phytoplasma solaniÕ and ÔCa. Phytoplasma trifoliiÕ are prevalent in peach growing areas in the central and north-western regions of Iran.

In recent years, almond witchesÕ-broom disease has been prevalent in almond growing areas in the centre and south of Iran. Furthermore, almond trees showing different symptoms of phytoplasma diseases such as little leaf, leaf rolling, dieback of branches, rosette and yellowing were observed in the central regions of Iran. DNA isolated from symptomatic almond trees was used to amplify 16S rDNA and 16S-23S rDNA intergenic spacer (IS) fragments by nested polymerase chain reaction (PCR) using phytoplasma universal primer pairs (P1 ⁄ P7, R16F2 ⁄ R2, PA2F ⁄ R and NPA2F ⁄ R). Phytoplasmas were detected in symptomatic almonds in two major almond-growing regions, Isfahan and ChaharMahal-O-Bakhtiari.Restriction fragment length polymorphism analyses of nested PCR products using endonuclease enzymes HpaII and TaqI revealed that phytoplasmas associated with infected almonds are genetically different. Sequence analyses of amplified fragments of 16S rDNA and IS region indicated that the almond phytoplasmas in Iran are closely related to ÔCandidatus (Ca.) Phytoplasma aurantifoliaÕ, ÔCa. Phytoplasma phoeniciumÕ, ÔCa. Phytoplasma solaniÕ and ÔCa. Phytoplasma trifoliiÕ. The phytoplasmas related to ÔCa. Phytoplasma aurantifoliaÕ were more prevalent than other phytoplasmas in the central regions of Iran.

Symptoms suggestive of phytoplasma diseases were observed in infected sweet cherry trees growing in the central regions of Iran. Phytoplasmas were detected in symptomatic trees by the nested polymerase chain reaction (nested PCR) using phytoplasma universal primer pairs (P1⁄Tint, PA2F⁄R, R16F2⁄R2 and NPA2F⁄R). Restriction fragment length polymorphism analyses of 485 bp DNA fragments amplified in nested PCR revealed that different phytoplamas were associated with infected trees. Sequence analyses of phytoplasma 16S rRNA gene and 16S-23S intergenic spacer region indicated that the phytoplasmas related to ÔCa. Phytoplasma asterisÕ and peanut WB group infect sweet cherry trees in these regions. This is the first report of the presence of phytoplasmas related to ÔCa. Phytoplasma asterisÕ and peanut WB group in sweet cherry trees.

Abstract:Recently, grapevines showing symptoms suggesting the 'bois noir' phytoplasma disease were observed in vineyards located in several central provinces of Iran. Polymerase chain reaction assays using phytoplasma universal primer pair P1A/P7A followed by primer pair R16F2n/R16R2 in nested PCR, confirmed the association of phytoplasmas with symptomatic grapevines. The results of RFLP analyses using HpaII, HinfI, MseI, RsaI, and TaqI restriction enzymes, indicated that grapevine phytoplasma isolates in these regions could be related to the 16SrXII group. Sequence analyses of the partial 16S rRNA gene confirmed that Iranian grapevine phytoplasmas are associated with 'Candidatus Phytoplasma solani'. This is the first report of the 'bois noir' disease outbreak in Iran.

Several annual field crops, vegetables, ornamentals, oilseed crops, and weeds showing phytoplasma diseases symptoms were collected to detect phytoplasmas related to ‘Candidatus Phytoplasma asteris’. The collecting was done in the central regions of Iran. For general detection of phytoplasmas, 16S rRNA gene fragments were amplified using phytoplasma universal primer pair P1/P7 in polymerase chain reaction (PCR) followed by primer pair R16F2n/R16R2 in nested PCR. Then, for finer detection of phytoplasmas related to ‘Ca. P. asteris’, DNA samples were used to extend the rp and tuf gene fragments by PCR using aster yellows group specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/rTufAy, respectively. Restriction fragment lenght polymorphism (RFLP) analysis of rp gene fragments using digestion with AluI, MseI, and Tsp509I restriction enzymes indicated that aster yellows group related phytoplasmas in these Iranian regions, belong to rpI-B subgroups. Sequence analysis of partial 16S rRNA and rp genes from representative phytoplasma isolates confirmed the RFLP results. This research is the first report of annual plants infected with phytoplasmas related to subgroup rpI-B in Iran.