Identification of phytoplasmas and their potential leafhopper vectors in vineyards of the East Mediterranean Region of Türkiye

Grapevine yellows (GY) is a destructive phytoplasma disease complex in viticultural regions worldwide, mainly associated with the presence of ‘Candidatus Phytoplasma solani’ (“bois noir”, 16SrXII-A) and 16SrV group phytoplasmas (“flavescence doree”). Field surveys in 2021-2022 in Hatay and Kahramanmaras (Türkiye) investigated phytoplasma occurrence in grapevines, weeds, and insect vectors. Typical GY symptoms were observed in grapevine and bindweed (Convolvulus arvensis). ‘Ca. P. solani’ was detected in one grapevine and one bindweed plants among the 25 grapevine and 19 bindweed samples tested by PCR and sequencing analysis. Among the 3,086 leafhoppers (28 species), 12 individuals from six species were positive for phytoplasmas, with the highest infection rates in Psammotettix provincialis, Empoasca sp. and Balclutha hebe. Sequencing confirmed ‘Ca. P. solani’ presence in three insect species, grapevine, and bindweed, while ‘Ca. P. mali’ (apple proliferation phytoplasma, 16SrX-A) was detected in six leafhopper individuals. These results provide the first molecular evidence of ‘Ca. P. solani’ and ‘Ca. P. mali’ in leafhoppers collected from vineyards in Türkiye and highlight the possible epidemiological role of diverse leafhopper species in GY spread.