Improvement of oil quality with enhanced fatty acid profiling in rapeseed (Brassica napus L.) seed via varietal screening and lipidomics (UPLC-MS) analysis

Rapeseed oil is widely considered amongst the healthiest edible oils owing to its attractive fatty acid composition. This study determines the fatty acid composition and key lipids of a diverse set of 25 commonly cultivated commercial rapeseed varieties under two distinct environments through targeted GC–MS and lipidomic analysis (UPLC-MS). Varieties Qinyou3 and Dadi199 exhibited the best seed quality, such as greater value of oleic acid, irrespective of the two experimental sites. Conversely, varieties Ganza1 and Shanyou28 showed lower seed quality in terms of fatty acid composition. A set of 923 lipid molecules were identified in seeds through UPLC-MS. The key differential lipids such as triglycerides (8:0/8:0/18:2, 18:4/18:1/18:1), were enriched significantly in high-quality varieties, i.e., Qingyou3. We further identified seven lipid modules and several critical triglycerides (i.e., 14:1e/10:1/10:4, 4:0/16:1/16:1) through the weighted co-expression network, and triglycerides were positively correlated with most types of fatty acids. Conversely, important lipids like ceramides were negatively correlated to seven types of fatty acid components. This study evidenced a strong relationship between fatty acid synthesis and lipids metabolism, which implied that biosynthesis of triglycerides and ceramides could be regarded as a promising intervention for selecting genotypes while breeding for improved seed quality. • The fatty acid composition of 25 rapeseed varieties was simultaneously assessed through NIR and targeted GC–MS. • The lipid profile of rapeseed oil was determined by Lipidomics (UPLC-MS). • The relationship between fatty acids and lipid profile was evaluated by co-expression analysis. • Several critical triglycerides were positively correlated with oleic and linoleic acids.