Fig. 6. Overview of exact GC-MS metabolic profiling of Arabidopsis genotypes . (a) heatmap with hierarchical clustering showing groups of metabolites that are significantly different (P< 0.0002, one-way ANOVA) between genotypes. Numbers refers to groups named on top left. (b) Standard error between 6 biological replicates, in % of average value, in each genotype. The red dotted line stands for the median value (9.7%). The dotted frame comprises metabolites that are also framed and named in panel (c). Data are shown as whisker plots with median, 25% and 75% quartiles, and interquartile range. (c) Relationship between average standard error (in % of overall mean) and relative signal (relative to sucrose set at 1) obtained on the GC-MS instrument (quantifying target mass). Metabolites that appear highly variable are framed (and are the same as metabolites framed in panel (b)). Note that metabolite 14 is labelled ”3-iodotyrosine” because it is identified with high certainty by Tracefinder® using the database although it is not expected in plants (see main text).