Metabolite-driven mechanisms reveal chemical ecology of Lehmann Lovegrass (Eragrostis lehmanniana) invasion in North American semi-arid ecosystems

Invasive plants threaten global ecosystems, yet traditional analyses of functional traits cannot fully explain their dominance over co-occurring natives. Metabolomics offers insights into plant invasions, but single-technique studies often miss critical biochemical mechanisms. We employ a multimodal metabolomics approach (¹H NMR, LC MS/MS, FT-ICR-MS, and MALDI-MSI) to investigate the biochemical basis of Lehmann lovegrass (Eragrostis lehmanniana) invasion in semi-arid North America, comparing it with a co-occurring native grass, Arizona cottontop (Digitaria californica). Our analysis reveals three metabolomic traits of Lehmann lovegrass compared to Arizona cottontop: Enhanced nitrogen allocation in shoots, reduced defensive metabolites in root layers; and increased root exudate modulation under stress conditions. These traits suggest Lehmann lovegrass succeeds through adaptation to increasing aridity rather than direct competition, demonstrating adaptation to nutrient-poor environments and high phenotypic plasticity in response to increasing aridity. This integrated metabolomic approach provides new mechanistic insights into invasion ecology and plant adaptation under environmental change.