Spatial and temporal variation in metabolic fingerprints of field-growing Myriophyllum spicatum

The investigation of submerged aquatic macrophytes in their natural habitat using metabolic fingerprinting may represent a comprehensive and sensitive approach in environmental sciences. The potential of metabolic fingerprinting for discriminating Myriophyllum spicatum individuals growing in different lakes under varying environmental conditions was explored to determine its applicability in an ecological context. Low molecular weight compounds from hydrophilic and lipophilic extracts of leaves from individual plants were analyzed using gas chromatography–mass spectrometry (GC–MS) with subsequent data preprocessing of the mass-to-charge fragments of metabolites using XCMS. Multivariate analysis was used to compare the metabolite composition of the plants in space and time at a fingerprint level. The technical variation in the signals was low compared with the biological variation between individuals. Variation of the metabolite composition of aquatic macrophytes retrieved at one site at a particular time was within the same range as described for algae and plants grown under controlled conditions in the laboratory. Thus, metabolic fingerprinting of M. spicatum growing in the field is reproducible and biological responses can be detected. As a “proof-of-principle”, the approach was applied to study individuals from two lake populations, as well as one population over a three week flowering period. Distinct metabolic fingerprints were found for the individuals from two lakes and were shown to be associated with the nutrient status of these lakes. For the population characterized over time, metabolic fingerprints of individuals seem to be related to their state of ontogenetic development. These results suggest that the lake water chemistry is reflected in the metabolite composition of the submerged macrophytes and that developmental changes may lead to metabolic alterations. We consider metabolic fingerprinting to be suitable for studying physiological processes of aquatic macrophytes in their habitat and potentially applicable for environmental monitoring.

► Metabolic fingerprints of an aquatic macrophyte from 2 lakes followed over 3 weeks.
► Reproducible fingerprints allow detection of biological responses in the field.
► Distinct plant metabolic fingerprints for two lakes related to lake water chemistry.
► Ontogenetic development leads to altered metabolite compositions and fingerprints.