Temporal sampling of root exudates using coated blade-SPME for decoding plant-pathogen interactions

Root exudates shape the rhizosphere and mediate plant-microbe interactions, yet traditional sampling techniques often disturb the natural environment. Here, we present the use of coated blade-solid-phase microextraction (CB-SPME) method for passive, non-invasive in situ temporal metabolomic profiling of pea (Pisum sativum) root exudates during infection by the soil-borne pathogen Aphanomyces euteiches. In comparison to previously established extraction techniques, CB-SPME delivered lower absolute recovery but superior reproducibility while maintaining sensitivity. This non-destructive approach preserves rhizosphere integrity, enabling continuous monitoring of dynamic metabolite fluctuations and offers new insights into how root exudate influences plant-microbiome interactions.