Expression profiles of VvWRKY genes in response to biotic stresses. (a) V. vinifera cv ‘Cabernet sauvignon’ and V. aestivalis cv ‘Norton’ plants were grown in an environmental chamber and inoculated with Erysiphe necator conidiospores (PM). Inoculated leaves were harvested at 0, 4, 8, 12, 24 and 48 h after inoculation (GEO series GSE6404). (b) Field-grown plants of V. vinifera cv ‘Chardonnay’ and ‘Incrocio Manzoni’ naturally infected with Bois Noir phytoplasma (BN), compared to healthy samples (GEO series GSE12842). (c) V. vinifera cv ‘Cabernet Sauvignon’ was infected with GLRaV-3 during véraison and the ripening stages of berry development (GEO series GSE31660). (d) qRT-PCR expression analysis of VvWRKY genes in Pinot PN40024 genotype infected with powdery mildew. Transcripts were normalized to actin gene expression. The means±s.d. of three biological replicates are presented. Asterisks indicate that the gene was significantly up- or downregulated in a given organ (*p≤0.05, **p≤0.01). GLRaV-3, grapevine leaf roll-associated virus-3.