Development of a root exudate collection protocol for metabolomics analysis using Nuclear Magnetic Resonance
Résumé
Large amounts of root exudates are released by plant roots into the soil. Due to their importance in regulating the
rhizosphere properties, it is necessary to unravel the precise composition and function of exudates at the root-soil
interface. However, obtaining root exudates without inducing artefacts is a difficult task. To analyse the low
molecular weight molecules secreted by pea roots, a protocol of root exudate collection was developed to
perform a metabolomics analysis using Nuclear Magnetic Resonance (NMR). To date a few NMR studies are
dedicated to root exudates. Plant culture, exudates collection and sample preparation methods had thus to be
adapted to the NMR approach. Here, pea seedlings were hydroponically grown. The obtained NMR fingerprints
show that osmotic stress increases the quantity of the exudates but not their diversity. We therefore selected a
protocol reducing the harvest time and using an ionic solvent and applied it to the analysis of faba bean exudates.
NMR analysis of the metabolic profiles allowed to discriminate between pea and faba bean according to their
exudate composition. This protocol is therefore very promising for studying the composition of root exudates
from different plant species as well as their evolution in response to different environmental conditions or
pathophysiological events.