Fig. 4

Impact of Trichoderma harzianum T22 inoculation on the metabolome of distant leaves from Nezara viridula-infested (a, b) or uninfested sweet pepper plants (c, d) (n = 5). (a) Volcano plot of damaged leaf samples from non-inoculated (CD_Dis, left side) and T. harzianum-inoculated plants (TD-Dis, right side). (b) Principal component analysis (PCA) plot of the metabolomes of distant leaf samples from non-inoculated (green) and T. harzianum-inoculated damaged plants (red). (c) Volcano plot of undamaged leaf samples from non-inoculated (CU-Dis, left side) and T. harzianum-inoculated plants (TU-Dis, right side). (d) PCA plot of the metabolomes of distant leaf samples from non-inoculated (green) and T. harzianum-inoculated (red) undamaged plants. The volcano plots display the t-test differences (log transformed) between the two treatments on the x-axis, and the negative logarithm of the t-test p-value on the y-axis. Coloured points on the left side of the line represent differentially accumulated metabolites (DAMs) with significant higher accumulation in the left side treatment, while the coloured points on the right side of the line represent DAMs with significant higher accumulation in the right-side treatment. Grey crosses indicate metabolites that do not show differential accumulation in any of the two treatments. The metabolomics features that showed the highest increase in one treatment compared with the other one are found towards the sides of the plot (on the left side in case of higher accumulation (a) CD-Dis or (c) CU-Dis, on the right side in case of higher accumulation in (a) TD-Dis or (c) TU-Dis), while the most statistically significant metabolomics features are found towards the top of the volcano plot