Fig. 4From: Accurate and easy method for systemin quantification and examining metabolic changes under different endogenous levelsGeneral outlook of the metabolic behaviour of the three genotypes of tomato plants using partial least squares, heatmap and clustering analysis. a 3D partial least squares plot explaining the major sources of variability for ESI (−) and ESI (+) signals obtained from a non-targeted analysis by UHPLC-QTOF MS in the three conditions BB, PS+ and PS−. Data points represent replicates of three independent experiments with two technical replicates per experiment and condition, which were injected randomly in the UHPLC-QTOF MS. Signals corresponding to different conditions were compared using the non-parametric Kruskal–Wallis test, and only data corresponding to p < 0.05 between groups were used for supervised analysis. b Heat map analysis and clustering of the different main signals corresponding to metabolite profiling, and generated with the Metaboanalyst 3.0 software, following a Kruskal–Wallis test (p < 0.05) in both ESI (−) and ESI (+) modes of ionizationBack to article page