First detection of ‘ <i>Candidatus</i> Phytoplasma trifolii’ in pistachio trees in Türkiye: A new and emerging threat

Abstract Pistachio ( Pistacia vera L.) is a vital crop for Türkiye's economy, occupying over 420 000 ha, primarily in south‐eastern Anatolia. In 2023, severe symptoms, such as curling, chlorosis and needle‐like leaf deformation, were observed on pistachio trees in Şanlıurfa Province. This prompted a molecular study of phytoplasma pathogens. A real‐time PCR targeting the 16SrDNA gene was used to analyse DNA from eight symptomatic and two asymptomatic trees. A phytoplasma was found in two symptomatic samples but not in asymptomatic controls. Positive samples were further analysed using nested PCR. One sequence with 99% identity to ‘ Candidatus Phytoplasma trifolii’ (16SrVI‐A subgroup) was found by bidirectional sequencing of PCR products. The identification of the phytoplasma was confirmed by a phylogenetic analysis showing the clustering of the UP 1 isolate with ‘ Ca. Phytoplasma trifolii’ reference strain and by a virtual RFLP analysis using 17 restrictions enzymes. This first report of ‘ Ca. Phytoplasma trifolii’ in pistachio in Türkiye highlights the presence of this phytoplasma in a key agricultural sector. Although no yield losses have been observed to date, broader surveys and monitoring of leafhopper vectors are necessary to assess the potential risk and implement timely management strategies.