Fig. 2: Root and rhizosphere metabolites involved in nitrogen use strategies.

Percentage of nitrogen-containing metabolites in root (a) and rhizosphere (e) by FT-ICR-MS, sample size = 36 each. b Potentially active organic nitrogen assimilation pathways in roots of invasive Lehmann lovegrass (ERLE) and native Arizona cottontop (DICA). Point plot on the right of each metabolite shows average normalized intensity and 95% confidence intervals. Pairwise comparisons through Dunn’s test are reported using compact letter display, where “a” represents the group with the highest mean rank. P values from Kruskal-Wallis tests annotated on the bottom right corner of each plot. c Relative intensity of three potential nitrogen carriers in plant roots from LC MS/MS. d Average intensity of three potential nitrogen carriers in plant roots from MALDI-MS (n = 24). Microscopic (left) and MALDI-MSI (right) images of one representative sample (highlighted with an open circle in the corresponding boxplot) of each nitrogen carrier from each plant species were shown on the right. f Nominal oxidation state of carbon (NOSC) of unique metabolites per plant species. g ChemRICH analysis of metabolite subclass identified through LC MS/MS and ¹H NMR, showing differential enrichment among plant species. Circle size indicates the number of metabolites within each subclass, ranging from 13 to 401. Insignificant (i.e., p > 0.05) or rare (number <10) subclasses were not shown.