Mining metabolic pathways in drought tolerance of Lolium multiflorum

To identify the important pathways related to the drought-resistant metabolic mechanism of ryegrass, the main metabolites of blue heaven were detected and studied by gas chromatography-mass spectrometry (GC-MS) under natural drought stress. Using partial least squares discrimination analysis and principal components analysis could completely distinguish between the control and drought stress group; furthermore, there were 19 metabolomic markers obtained by the s-plot analysis. Abundance of 10 biomarkers decreased, namely itaconic acid, taurine, sucrose, glucose, lysine, isoleucine, tyrosine, asparagine, myo-inositol, 1-aminocyclopropane-1-carboxylic acid. Abundance of nine biomarkers increased, namely fructose, phenylalanine, homoserine, 1-hydrogen indole, threonine, phosphate, creatinine, citric acid, malic acid. Enriched pathway analysis by MetaboAnalyst 4.0 obtained nine significant metabolic pathways (P < 0.05), namely Ascorbate and aldarate metabolism; Glycine, serine and threonine metabolism; Alanine, aspartate and glutamate metabolism; Citrate cycle (TCA cycle); Galactose metabolism; Aminoacyl-tRNA biosynthesis; Arginine and proline metabolism; Lysine biosynthesis; Cyanoamino acid metabolism. The nine pathways were associated with drought resistance of ryegrass. The main metabolic pathways of Lolium multiflorum under drought stress were identified through the study, which is of great significance to explore the mechanism of drought resistance metabolism of Lolium multiflorum and would provide reference for further promotion of Lolium multiflorum.