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In two of Iran's central provinces, several herbaceous plants showing phytoplasma disease symptoms were collected to detect 'Canididatus Phytoplasma asteris'-related phytoplasmas. Confirmation of an association of phytoplasmas with diseased plants was done using polymerase chain reaction (PCR) assays having the phytoplasma universal primer pairs P1/P7 followed by R16F2n/ R16R2 in nested PCR. Then, for detection of 'Ca. P. asteris', DNA samples were subjected to amplification of rp and tuf genes using specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/rTufAy, respectively. Restriction fragment length polymorphism or RFLP analyses of rp gene fragments using Tsp509I restriction enzyme as well as sequence analyses indicated that 'Ca. P. asteris'-related phytoplasmas associated with carrot, niger seed and scallion plants in these regions, belong to the rpI-L subgroup. This research is the first report of carrot, niger seed, and scallion infection with phytoplasmas belonging to the rpI-L subgroup.
Recently, Russian olive trees showing witches’-broom and little leaf symptoms have been widely observed in northwestern and central Iran. Polymerase chain reaction (PCR) and nested PCR assays using phytoplasma universal primer pairs confirmed phytoplasma symptomatic infection of trees. Sequence analyses showed that ‘Candidatus Phytoplasma asteris’ was the causal agent of the disease in these regions. However, RFLP results using restriction enzymes HpaII, EcoRI, HinfI and AluI indicated that the collected isolates in these regions are genetically different. In addition, leafhopper Macropsis infuscata was recognized as a possible insect vector of the disease for the first time.
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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.
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