Figure 2
Profiles of volatile organic compounds (VOCs) of grapevine leaves. Susceptible (Pinot noir; PN) and resistant grapevine plants [BC4, Kober 5BB (KBB), SO4, and Solaris (SOL)] were inoculated with Plasmopara viticola and VOCs were detected before inoculation (0 dpi) and six days post inoculation (6 dpi) with P. viticola in two greenhouse experiments (Supplementary Tables S1 and S2). Three pairwise comparisons were carried out between VOC abundance in each resistant genotype and Pinot noir at 0 dpi (R vs. PN 0 dpi) or at 6 dpi (R vs. PN 6 dpi) and between 6 and 0 dpi for each genotype (6 vs. 0 dpi). Green and red cells indicate significantly higher and lower VOC abundance (Kruskal-Wallis test p ≤ 0.05 and fold change ≥ 1.5) in two (dark colour) or one (light colour) experiment, respectively. Metabolite groups were identified according to the VOC profiles: higher abundance in all resistant genotypes in both experiments at 6 dpi (Group 1), higher abundance in two or more resistant genotypes in both experiments at 6 dpi (Group 2), VOCs with a higher abundance in only one resistant genotype in both experiments at 6 dpi (Group 3), VOCs with a lower abundance in at least one resistant genotype in both experiments (Group 4) as compared with Pinot noir.
