BACKGROUND Sesame (Sesamum indicum) can accumulate over 60% oil in its seed. However, low oil content genotypes with an oil content of less than 50% are also observed. To gain insights into how genes shape this variation, we examined 22 seed and carpel transcriptomes from 3 varieties of sesame with high and low oil content. RESULTS A total of 34.6~52.2% of the sesame genes were expressed with a RPKM greater than 5 in the 22 tissue samples. The expressed gene numbers tended to decrease in the seed but fluctuated in the carpels from 10 to 30 days post-anthesis (DPA). Compared with that of the low oil content sesames, the high oil content sesame exhibited more positive gene expression during seed development. Typically, genes involved in lipid biosynthesis were enriched and could distinguish the high and low genotypes at 30 DPA, suggesting the pivotal role of seed oil biosynthesis in the later stages. Key homologous lipid genes that function in TAG biosynthesis, including those that encoded glycerol-3-phosphate acyltransferase (GPAT), acyl-CoA:diacylglycerol acyltransferase (DGAT), and phospholipid:diacylglycerol acyltransferase (PDAT), were strengthened asynchronously at different stages, but the lipid transfer protein (LTP)-encoding genes, including SIN_1019175, SIN_1019172 and SIN_1010009, usually were highlighted in the high oil content sesames. Furthermore, a list of 23 candidate genes was identified and predicted to be beneficial for higher oil content accumulation. Despite the different gene expression patterns between the seeds and carpels, the two tissues showed a cooperative relationship during seed development, and biological processes, such as transport, catabolic process and small molecule metabolic process, changed synchronously. CONCLUSIONS The study elucidated the different expression profiles in high and low oil content sesames and revealed key stages and a list of candidate genes that shaped oil content variation. These findings will accelerate dissection of the genetic mechanism of sesame oil biosynthesis.

中文翻译：

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塑造高和低含油量芝麻的基因表达谱。

背景技术芝麻（Sesamum indicum）可以在其种子中积聚超过60％的油。但是，还观察到了油含量低于50％的低油含量基因型。为了深入了解基因如何形成这种变异，我们检查了来自3个芝麻品种的高油含量和低油含量的22个种子和心皮转录组。结果在22个组织样本中，芝麻基因表达率为34.6〜52.2％，RPKM大于5。花后10到30天（DPA），表达的基因数量倾向于在种子中减少，但在心皮中波动。与低油芝麻相比，高油芝麻在种子发育过程中表现出更多的正基因表达。通常，参与脂质生物合成的基因会被富集，并可以区分30 DPA时的高和低基因型，提示了种子油在后期生物合成中的关键作用。在TAG生物合成中起作用的关键同源脂质基因，包括编码3-磷酸甘油酰基转移酶（GPAT），酰基-CoA：二酰基甘油酰基转移酶（DGAT）和磷脂：二酰基甘油酰基转移酶（PDAT）的那些，在不同阶段被异步增强，但高油含量芝麻中通常会突出显示编码脂质转运蛋白（LTP）的基因，包括SIN_1019175，SIN_1019172和SIN_1010009。此外，鉴定了23个候选基因的列表，并预测它们对更高的含油量积累是有益的。尽管种子和心皮之间的基因表达方式不同，但两种组织在种子发育和生物学过程（例如运输，分解代谢过程和小分子代谢过程同步变化。结论该研究阐明了高和低含油量芝麻中的不同表达谱，并揭示了关键阶段和影响含油量变化的候选基因列表。这些发现将加速解剖芝麻油生物合成的遗传机制。