Evaluation of lipid and metabolite profiles in tobacco leaves from different plant parts by comprehensive lipidomics and metabolomics analysis

Tobacco is an agricultural product with extremely high economic value. Manufacturers have realized that the chemical nature of fresh tobacco leaves influences the flavor properties of tobacco products. To explore the key components that cause the differences in tobacco leaves, high-precision mass spectrometry was employed for multi-omics analysis of three groups (upper, middle, and lower parts) of tobacco leaves. The results showed that the fresh leaves from different parts of Yunyan 87 tobacco plant had significant differences. It was not unique compounds that caused these differences, but more likely variations in shared compounds. The species of glycerolipids, glycerophospholipids, and fatty acyls were the most numerous, their numbers account for 76.68% of total lipids components. The number of glycerolipids accounted for 70% of the identified key lipid components, with the majority being polyunsaturated glycerolipids. It suggested that the disparities in polyunsaturated glycerolipids were the primary cause of lipids differentiation in fresh leaves from different parts. Glycerolipids are effective storage forms of carbon and energy. Carbohydrates and carbohydrate conjugates are the main products of tobacco photosynthesis. In key components, they had the highest relative abundance in the lower leaves. In addition, terpenoids, and organic oxygen compounds, all exhibit high relative abundances in the lower leaves. Amino acids, peptides, and analogues were more abundant in the upper leaves. Differences in the chemical composition of fresh tobacco will result in different sensory qualities and styles. In addition to providing insights into the differences and diversity of tobacco leaves in various parts of the plant during growth, the results present potentially rewarding information for directional cultivation of tobacco plants, grading of tobacco leaves, and optimization of resource utilization.