Phytoplasmas are a group of plant pathogens in the Acholeplasmataceae family that thrive in the phloem of their host plants. They cause a wide range of symptoms that may differ based on the plant species and the specific phytoplasma strain. We collected 160 grapevine samples that showed typical phytoplasma symptoms, including leaf reddening, yellowing, curling, blight, dried spots on fruits, and slow tree decline. Samples were collected during the spring and summer (June and late September) and autumn (early October) of 2017 and 2018. DNA was extracted from 100 symptomatic samples and subjected to nested PCR targeting the 16S rDNA region. Phylogenetic and virtual RFLP analysis revealed the presence of two major phytoplasma groups: 16SrIX (Candidatus Phytoplasma phoenicium) and 16SrXII (Candidatus Phytoplasma solani). Detecting these groups, known for their wide host range and potential for vector transmission, underscores the epidemiological risk to viticulture in northwestern Iran and neighboring regions. This study reports, for the first time, the presence and molecular identification of phytoplasma strains infecting grapevines in East and West Azerbaijan provinces of Iran—a major grape-producing area bordering Türkiye and central Asia. These findings contribute to the broader understanding of the epidemiology of grapevine yellows in west and central Asia and have implications for disease monitoring and management in grapevine production.
