Solanum tuberosum (potato) wildtype and overexpression lines with an enhanced Phytophtora infestans resistance were analysed for their metabolic response to simulated herbivory.

• Using the data acquired with Bruker LC-ESI-Q-TOF MS and MS/MS instrumentation and methods, the MetaboScape software provided an efficient platform for the straightforward linkage of structural similarities and metabolite abundances. We used various statistical tools (PCA, t-test) in MetaboScape to focus on relevant features. The unsupervised MS/MS similarity metabolite profiling approach enabled a rapid annotation of 17 metabolites which were previously unknown in our analyses.

• The common abundance patterns together with common MS/MS patterns pointed to an overflow of the hydroxycinnamic acid amide biosynthesis in the AtACT-AtDTX18 overexpression lines. This is in perfect accordance with the function of the overexpressed enzyme AtACT that is responsible for the biosynthesis of four HCAAs. The increase of the many other HCAAs might be a metabolic side effect of the plant to compensate for this overflow and to bypass toxic effects for the cell. MetaboScape was very valuable for easy data processing, the annotation of many formerly unknown compounds and an intuitive visualization of metabolic changes.