NMR and LC-MS-Based Metabolomics to Study the Effect of Surfactin on the Metabolome of Flax

Flax (Linum usitatissimum) is a versatile plant used in a range of applications, from textiles to nutrition. Surfactin, a cyclic lipopeptide biosurfactant produced by bacteria such as Bacillus subtilis, has potential as a biocontrol agent or as a plant defense inducer in agriculture. This work aims to determine the effects of surfactin treatment at two kinetic points on the metabolism of flax hydroponic cultures, using advanced metabolomic techniques, including 1H NMR and LC-MS analyses. Surfactin, detected in the roots, has a significant local impact on the metabolic profiles of flax roots, leading mainly to a higher content of cyanogenic compounds and amino acids and a lower content of carbohydrates. Surfactin, which is not detected in the aerial parts, also induces contrasted changes in amino acids, sugars, and secondary metabolite accumulation between stems and leaves. Surfactin treatment of flax leads to both a local and systemic effect on flax metabolism. These changes suggest that plant response to surfactin treatment could induce an enhanced plant defense. This could suggest potential applications of surfactin in the agricultural field as a biostimulant or biocontrol agent, to limit the use of chemical compounds in culture, and to limit their negative impact on both health and the environment.