Correlation analysis of the transcriptome and metabolome reveals the regulatory network for lipid synthesis in developing Brassica napus embryos
In this manuscript, we explored the key molecular networks for oil biosynthesis with the transcriptome and metabolome of B. napus embryo at different developmental stages.
Brassica napus (B. napus) is an important oil crop worldwide, yet the molecular pathways involved in oil biosynthesis in seeds are not fully understood. In this study, we performed a combined investigation of the gene expression profiles and metabolite content in B. napus seeds at 21, 28 and 35 days after flowering (DAF), when seed oil biosynthesis takes place. The total triacylglycerol (TAG) content in seed embryos increased over the course of seed maturation, and was accompanied by changes in the fatty acid profile, an increase in lipid droplets, and a reduction in starch grains. Metabolome analysis showed that the total amino acid, free fatty acid and organic acid contents in seed embryos decreased during seed maturation. In total, the abundance of 76 metabolites was significantly different between 21 and 28 DAF, and 68 metabolites changed in abundance between 28 and 35 DAF. Transcriptome analysis showed that the set of genes differentially expressed between stages was significantly enriched in those related to lipid metabolism, transport, protein and RNA metabolism, development and signaling, covering most steps of plant lipid biosynthesis and metabolism. Importantly, the metabolite and gene expression profiles were closely correlated during seed development, especially those associated with TAG and fatty acid biosynthesis. Further, the expression of major carbohydrate metabolism-regulating genes was closely correlated with carbohydrate content during seed maturation. Our results provide novel insights into the regulation of oil biosynthesis in B. napus seeds and highlights the coordination of gene expression and metabolism in this process.
KeywordsBrassica napus Oil accumulation Seed Transcriptome Metabolome
This work was supported by the NSFC Project (31671730), the National Key R&D Program of China (2016YFD0100506) and the Fundamental Research Funds for the Central Universities (KYZ201301 and KJSY201510).
TH, XX, QX, SX, WX, LX, SX and ZJ carried out the experiments. TH drafted the manuscript. TH and XX conceived and designed the study and finalized the manuscript. All the authors have read and approved the final manuscript.
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