Lipidomic and transcriptomic profiles of lipid biosynthesis and accumulation during seed development in sesame

Abstract

Abstract Background Sesame is one of the most important oilseed crops and attracts significant attention because of its huge nutritional capacity. However, the molecular mechanisms underlying oil accumulation in sesame remains poorly understood. Results In this study, lipidomic and transcriptomic analyses in different stages of sesame seed (Luzhi No.1, seed oil content is 55.67%) development were performed to gain insight into the regulatory mechanisms that govern differences in lipid composition, content, biosynthesis, and transport. In total, 481 lipids, including fatty acid (FA, 38 species), triacylglycerol (TAG, 127 species), ceramide (33 species), phosphatidic acid (20 species), and diacylglycerol (17 species), were detected in developing sesame seeds using gas and liquid chromatography-mass spectrometry. Most FAs and other lipids accumulated 21–33 days after flowering. RNA-sequence profiling in developing seeds highlights the enhanced expression of genes involved in the biosynthesis and transport of FAs, TAGs, and membrane lipids, which is similar to that in the process of lipid accumulation. Through the differential expression analysis of genes involved in lipid biosynthesis and metabolism during seed development, several candidate genes were found to affect the oil content and FA composition of sesame seeds, such as ACCase, FAD2, DGAT, G3PDH, PEPCase, WRI1 and WRI1-like genes. Conclusions Our study firstly provides the patterns of lipid accumulation and biosynthesis-related gene expression and lays an important foundation for the further exploration of sesame seed lipid biosynthesis and accumulation.