Growth, ROS Markers, Antioxidant Enzymes, Osmotic Regulators and Metabolic Changes in Tartary Buckwheat Subjected to Short Drought

Tartary buckwheat (Fagopyrum tataricum) is an important pseudocereal feed crop with medicinal and nutritional value. Drought is one of the main causes of reduced growth and yield in these plants. We investigated the growth, physiological, and metabolic responses of the widely promoted Tartary buckwheat variety Chuan Qiao No. 1 to polyethylene glycol (PEG)-mediated drought stress. Drought significantly decreased shoot length, shoot biomass and relative water content. Root length, malondialdehyde content, electrolyte leakage, activities of superoxide dismutase, peroxidase, catalase and amylase, and contents of soluble sugar, soluble protein and proline were increased by PEG-mediated drought. Untargeted metabolomics analysis identified 32 core metabolites in seedlings subjected to PEG-mediated drought, 16 of which increased- including quercetin, isovitexin, cyanidin 3O-beta-D-glucoside, L-arginine, and glycerophosphocholine, while the other 16 decreased-including 3-methoxytyramine, 2, 6-diaminopimelic acid, citric acid, UDP-alpha-D-glucose, adenosine, keto-D-fructose. The 32 core metabolites were enriched in 29 metabolic pathways, including lysine biosynthesis, citrate (TCA) cycle, anthocyanin biosynthesis, and aminoacyl-tRNA biosynthesis. Among them, taurine and hypotaurine metabolism, flavor and flavor biosynthesis, indole alkaline biosynthesis, and alanine, aspartate and glutamate metabolism were the four main metabolic pathways affected by drought. Our findings provide new insights into the physiological and metabolic response mechanisms of Tartary buckwheat to drought stress.