Identification of phytoplasmas associated with grapevine yellows in Serbia.

The molecular identification and characterization of phytoplasmas infecting grapevine in four locations of different grape-growing regions of Serbia is reported. Samples from symptomatic and asymptomatic grapevine plants were collected during 2002 and 2003. Detection and identification of phytoplasmas were done by the restriction fragment length polymorphism analysis (RFLP) of polymerase chain reaction (PCR) amplified 16S rDNA. Grapevine yellows were associated with three molecularly distinguishable phytoplasmas. Flavescence dorée phytoplasmas (elm yellows group - 16SrV-C subgroup) were present only in the Župa Aleksandrovac region; in other surveyed regions Bois noir phytoplasmas (stolbur group - 16SrXII-A subgroup) were detected; a mixed infection of European stone fruit yellows (apple proliferation group - 16SrX-B subgroup) and Bois noir phytoplasmas was identified in one sample. A finer molecular characterization by the RFLP analysis on rpS3 and SecY genes of Flavescence dorée phytoplasmas from Župa Aleksandrovac allowed to verify that the Serbian genotype is indistinguishable from a strain from the Veneto region, Italy. Characterization performed on tuf gene of Bois noir phytoplasmas showed lack of amplification of samples from Erdevik. The identity of HpaII profiles on the tuf gene PCR products was observed between samples from Palić and Radmilovac, this pattern appears indistinguishable from one of the two profiles obtained in samples from the Italian grapevines used as reference strains.