Central metabolic processes of marine macrophytic algae revealed from NMR based metabolome analysis

Abstract

Metabolites, the regulatory components of cellular functioning, represent the biological phenomes. Metabolome profile of select marine macrophytic algal species of Chlorophyta, Rhodophyta and Phaeophyta were characterized for the first time using NMR spectroscopy. A facile and tractable method suitable for metabolite profiling in marine macroalgal species was also developed and validated against the one commonly employed for terrestrial plants. The identified metabolites and their fluxes enabled to gain newer insights into the biochemical regulations adaptive to marine environment. Among the salient metabolites identified, lignin precursors (acetates of guaiacyl and syringyl units) in Ulva lactuca support the hypothesis of conserved evolution of lignification trait. Also, the metabolites of non-neuronal cholinergic system and non-proteinaceous cysteine-sulfinic acid oxoforms identified in this study are the constituents of redox sensing mechanism. Further, the fluxes of lactate and acetate are indicative for the regulatory switching of oxidative respiration to fermentative glycolysis. The biological functions of identified metabolites were then associated with the known metabolic pathways in a metabolic model summarizing the central metabolic processes of marine macroalgae.