Metabolic profiling allows comprehensive phenotyping of genetically or environmentally modified plant systems

Metabolic profiling using gas chromatography-mass spectrometry technologies is a technique whose potential in the field of functional genomics is larg ely untapped, To demonstrate the general usefulness of this technique, we a pplied to diverse plant genotypes a recently developed profiling protocol t hat allows detection of a wide range of hydrophilic metabolites within a si ngle chromatographic run. For this purpose, we chose four independent potat o genotypes characterized by modifications in sucrose metabolism. Using dat a-mining tools, including hierarchical cluster analysis and principle compo nent analysis, we were able to assign clusters to the individual plant syst ems and to determine relative distances between these clusters. Extraction analysis allowed identification of the most important components of these c lusters. Furthermore, correlation analysis revealed close linkages between a broad spectrum of metabolites. In a second, complementary approach, we su bjected wild-type potato tissue to environmental manipulations, The metabol ic profiles from these experiments were compared with the data sets obtaine d for the transgenic systems, thus illustrating the potential of metabolic profiling in assessing how a genetic modification can be phenocopied by env ironmental conditions. In summary, these data demonstrate the use of metabo lic profiling in conjunction with data-mining tools as a technique for the comprehensive characterization of a plant genotyp.