Phytoplasmas are known as a serious threat for cultivation of important plants and cause 700 diseases in fruit trees, forage crops, ornamental, vegetables and wild plants. In central part of Iran, phytoplasma diseases are the causative agent of yellowing, whitches’ broom, stunting and malformation in many important crops. Recently several symptoms of Phytoplasmal diseases have been found associated with forage crops in different areas of Isfahan province. Affected plants exhibit chlorosis, leaf stunting, growth reduction, rosette and witches’ broom symptoms and the damages are significantly increasing in alfalfa growing regions. Since different phytoplasmas are prevalent in crop growing area of Isfahan and seems that phytoplasmas have expanded their host range in the region to include legume cro therefore, the present investigation was aimed at identification and the samples were separated into three groups I, II, III. The PCR-RFLP patterns of samples in group I were correlated to the profile of Candidatus Phytoplasma solani (group 1), while the members of group II were identified as Ca. Phytoplasma aurantifolia . The samples yielded indistinguishable RFLP patterns were placed in group III. Nucleotide sequencing of four representatives from each group showed high similarities (99%) of the members of Group I to the sequences of known Ca. phytoplasma solani and group II to Ca. Phytoplasma aurantifolia deposited in the GenBank database. Despite having a different RFLP type, in sequence analysis, all of the members in group III were identified as Ca. Phytoplasma aurantifolia except an isolate which had high homology to Candidatus Phytoplasma solani. Thus it seems that RFLP analysis of the 16rDNA region of phytoplasma is not a useful method for genotyping of phytoplasmas. The results demonstrated that Key words : Identifiication, Phytoplasma, Nested-PCR, PCR-RFLP, Ca. phytoplasma solani, Ca. Phytoplasma aurantifolia
