Fig. 4

Relative expression levels of the whole set of the Vitis vinifera stilbene synthase genes (VvSTS) in the leaves of the nine grapevine genotypes of Fig. 1 collected before inoculation with Plasmopara viticola. The letter denoting the phylogenetic group to which each gene belongs is given in parentheses. For each gene, relative expression levels were calculated by setting a value of 1 for the lowest value among the nine genotypes. Normalization and sample replication as in Fig. 3. Different letters denote significant differences according to the Tukey’s test (p ≤ 0.01). Grapevine genotypes: CHA = Chasselas, ALE = Aleatico, CAN=Canaiolo nero, TRE = Trebbiano toscano, ROS = Rossetto, ROM = Romanesco, SYL = accession of V. vinifera subsp. sylvestris, ISA = Isabella, SOL = Solaris