Quantitative metabolic and lipidomic phenotypes of C3, C3-C4 intermediate and C4 species in genus Flaveria

C4 photosynthesis has complex traits with high light, nitrogen and water use efficiencies. To study the carbon and nitrogen stoichiometry coupled in the systematic metabolism along the path from C3 to C4, we applied the nuclear magnetic resonance (NMR)-based metabolomic and advanced lipidomic approaches to profile the 38 metabolites and 246 lipids for typical C3 ancestor, C3-C4 intermediates and C4 species in Flaveria leaves. Our results showed that a typical feature of metabolism related to amino acids/ amine, organic acids, choline/ its derivates and phospholipids showed the dominant abundance along the path from C3 to C4, which were implicated in different cellular responses with obvious functional tendencies toward protein synthesis and degradation, tricarboxylic acid cycle, and oxidation stress. Conversely, the metabolism related to carbohydrates and lipids biosynthesis tended to decrease along the path from C3 to C4. Among C3-C4 intermediates, the type II F. ramosissima was special to own the metabolic characteristics of both C3 species with high carbohydrates and C4 species with high level of amino acids and organic acids. Taking together, the comprehensive phenotype characterized the unique metabolites of photosynthetic metabolism in Flaveria representing C3, C3-C4 intermediate and C4 species, which provided metabolic insight into C4 photosynthetic evolution.