Ecometabolomic analysis of the effect of more persistent precipitation regimes reveals common and tolerance related metabolic adjustments in four grassland species

Abstract

Climate change is inducing more persistent precipitation regimes (PRs) in the mid-latitudes, characterized with both longer dry and longer wet periods. Such PRs could potentially result in water deficiency, as well as water logging stress. However, the effects of persistent PRs on plant metabolism remain largely unknown. We applied an 8-level PR of increasingly longer alternating dry and wet periods over 120 days to grassland mesocosms and analysed the metabolomic profiles of four species with varying sensitivity to PRs (Holcus lanatus, Phleum pratense, Centaurea jacea, Plantago lanceolata). The metabolome of the most sensitive species Centaurea jacea showed a clear tipping point at a mild PR (10-day dry/wet), while in the other species this happened at more persistent PRs. Amino acids accumulation was a general response across all species. This was more evident in the tolerant species Phleum. Phenylalanine metabolism, alanine, aspartate and glutamate metabolism pathways were highly involved in PR responses in four species. Fewer phenylpropanoids were changed significantly under more persistent PRs in Centaurea than in the remaining species. These results suggest that the accumulation of amino acids and modulation of secondary metabolism may be key factors limiting metabolic acclimation of sensitive species in response to more persistent PRs.