Transcriptional changes in Flavescence dorè infected and recovered under field conditions

Phytoplasmas have become increasingly important as serious threats to vineyard survival in several grape growing areas. Flavescence dorèe (FD) in particular, may cause epidemics with a consequent important economic loss, and is subjected to quarantine restrictions in Europe. During the 2013 vegetative season, samples of healthy, FD-infected and FD-recovered grapevines were collected from a long term monitored vineyard. Two cultivars, Nebbiolo and Barbera, characterized by a diverse susceptibility to the infection and by a different recovery rates were selected. About 20 samples were collected for each phytosanitary status and cultivar, in three phenological stages, and subjected to molecular analyses to ascertain the presence of phytoplasmas and other grapevine viruses. Subsets of healthy, recovered and FD-infected grapevines of each cv, sampled in July and August, were chosen for gene expression analyses. A list of 20 genes, whose expression is presumably altered in recovered grapevines compared to infected and healthy ones, were selected on the basis of the available literature and preliminary studies. For each selected gene, a Real-Time PCR protocol, using SyberGreen chemistry, was optimized. Aim of the work was to identify deregulated grapevine genes that can be considered markers of FD recovered grapevines under field conditions.