PNNL

Abstract

Peatlands are efficient in storing carbon, largely due to inhibition of microbial degradation of peatland litter by Sphagnum mosses. It is crucial to characterize the organic compounds underlying this carbon sequestration phenomenon, especially in the face of climate variability. Mass spectrometry and liquid state NMR were utilized to provide a comprehensive and novel characterization of the metabolite and lipid profiles of Sphagnum fallax. A total of 418 putative metabolites were detected – 298 were novel, 120 were previously unknown to be present in Sphagnum fallax—and one hundred fifty-two lipids, thirty-one of which were unknowns. Three fungal metabolites were identified providing insights on fungal colonization that may benefit Sphagnum. Seventeen compounds with previously known antimicrobial activity were detected in Sphagnum, and an additional 232 possible antimicrobial compounds that supports the hypothesis of Sphagnum-induced microbial inhibition. The application of HR MS and NMR enabled the full characterization of metabolome and lipidome profiles of Sphagnum fallax. Understanding the molecular composition of Sphagnum provides a much-needed baseline to pair structure to function to begin to understand how Sphagnum acts on its environment and provides key biomarkers to predict peatland C store changes (accumulation, sequestration, emissions) as climate shifts.