Lipidomic remodeling in Cannabis sativa L. under cold tolerance

In order to explore the lipidomic remodeling mechanisms and biological basis of hemp response to cold stress, the physiological and biochemical indices of hemp were analyzed, and a regulatory network for lipid metabolism under cold stress (4 ℃) was constructed. The results revealed that cold stress, inhibited the growth and development of hemp, with the total fresh weight decreasing by 29∼37 %, and the total dry weight decreasing by 17∼22 %. Additionally, the photosynthesis system was damaged, prompting plants to produce osmotic regulators and activate protective enzymes. Lipidomic analysis revealed that galactolipids, including MGDG, DGDG, and SQDG, were the dominant membrane lipids in hemp leaves, accounting for 70 % of the total membrane lipid components. Notably, some lipid remodeling was observed in hemp leaf tissue 3 d after cold stress treatment. Specifically, higher PC/PE and DGDG/MGDG ratios, along with a 53 % increase in PA levels, highlighted the critical role of membrane lipid remodeling and fatty acid unsaturation in hemp adaptation to cold stress. The transcriptomic analysis revealed that the lipid metabolism pathways were activated, with 732 genes associated with lipid metabolic pathways were identified. These genes were primarily enriched in the pathways related to TAG synthesis, fatty acid metabolism, and membrane lipid metabolism. A novel metabolic regulatory network for hemp lipids under cold stress was constructed, offering some insights into the molecular events underlying changes in membrane lipids during cold stress and identifies the key lipids and pathways responsible for resilience to such stress, thereby facilitating the development of new approaches for crop tolerance to stress.