Lipidomic and metabolomic analyses reveal changes of lipids and metabolites profile in rapeseed during nitrogen deficiency.

Nitrogen is one of the most essential macronutrients for plant growth and its availability in soil is vital for agricultural sustainability and productivity. However, excessive nitrogen application could reduce the nitrogen use efficiency and produce environmental pollution. Here, we systematically determined the response in lipidome and metabolome in rapeseed during nitrogen starvation. Plant growth was severely retarded during nitrogen deficiency, while the levels of most amino acids was significantly decreased. The levels of monogalactosyl diacyglycerol (MGDG) in leaves and roots was significantly decreased, while the level of digalactosyl diacylglycerol (DGDG) was significantly decreased in roots, resulting in significant reduction of MGDG/DGDG ratio during nitrogen starvation. Meanwhile, the levels of sulfoquinovosyl diacylglycerol, phosphatidylglycerol and glucuronosyl diacylglycerol was reduced to varying extents. Moreover, the levels of metabolites in the tricarboxylic acid cycle, Calvin cycle, and energy metabolism was changed during nitrogen deficiency. These findings show that nitrogen deprivation alters the membrane lipid metabolism and carbon metabolism, and our study provides valuable information to further understand the response of rapeseed to nitrogen deficiency at metabolism level.