Metabolic profiles of pop2-1 upon NaCl treatment. Main polar metabolites occurring in roots and shoots of WT and pop2-1 were determined in 14-day-old plantlets treated for 4 days with 150 mM NaCl. Amino acids, excepted serine, were determined using Acquity UPLC system, other metabolites were determined using GC-MS system. (A) GABA content in pop2-1 mutant upon NaCl. (B) Principal component analysis of metabolite profiling data. Samples plot on the first two principal components (PCs) is shown. (C-D) Comparison of metabolite levels in WT and pop2-1 roots (C) and shoots (D). Only metabolites showing a significantly different content between pop2-1 and WT (Mann-Whitney U-Test, P < 0.05) in at least one condition (Control or NaCl) were considered. Quotients of mean content of pop2-1 (n = 3) over WT (n = 3) were plotted on a logarithmic scale (log2). Values < 0 represent a lower content in pop2-1 compared to WT; values > 0 represent a greater content in pop2-1 compared to WT. Stars indicate a significant difference between pop2-1 mutant and WT according to non-parametric Mann-Whitney U-test (P < 0.05).