油菜(BrassicanapusL.;AACC)是世界上重要的含油作物。温度显著影响油料作物的产量;然而,温度促进油生物合成的潜在机制仍然未知。在这项研究中,我们发现,温度敏感的品种(O)可以在夜间低温下积累更高的种子油含量(LNT,13°C)与温度不敏感的品种(S)相比。我们对在不同夜间温度下生长的两个品种的种子进行了深入的转录组分析。我们发现,夜间低温会引起两个品种种子中转录模式的显着变化。相比之下,在夜间低温下,与脂肪酸和脂质途径相关的基因在O品种中的表达高于S品种。在这些基因中,我们确定了14个与石油生产相关的基因,尤其是BnLPP和ACAA1,与S相比,它们在O品种中响应于夜间低温而显着上调。WGCNA分析和qRT-PCR验证表明,这些基因主要受5种转录因子调控,WRKY20、MYB86、bHLH144、bHLH95和NAC12,在LNT下,其表达在O中也比在S中增加。这些结果阐明了O品种在LNT条件下石油积累的可能分子机制。随后的生化试验证实,BnMYB86转录激活了BnLPP的表达,有助于石油积累。同时,在LNT,这些基因在植物中的表达水平高于夜间高温,DEG(SUT,PGK,PK,GPDH,ACCase,SAD,KASII,LACS,FAD2,FAD3,KCS,KAR,ECR,GPAT,LPAAT,PAP,DGAT,与脂质生物合成相关的STERO)也被上调,其中大部分用于石油积累。
Rape (Brassica napus L.; AACC) is an important oil-bearing crop worldwide. Temperature significantly affects the production of oil crops; however, the mechanisms underlying temperature-promoted oil biosynthesis remain largely unknown. In this study, we found that a temperature-sensitive cultivar (O) could accumulate higher seed oil content under low nighttime temperatures (LNT,13°C) compared with a temperature-insensitive cultivar (S). We performed an in-depth transcriptome analysis of seeds from both cultivars grown under different nighttime temperatures. We found that low nighttime temperatures induced significant changes in the transcription patterns in the seeds of both cultivars. In contrast, the expression of genes associated with fatty acid and lipid pathways was higher in the O cultivar than in the S cultivar under low nighttime temperatures. Among these genes, we identified 14 genes associated with oil production, especially BnLPP and ACAA1, which were remarkably upregulated in the O cultivar in response to low nighttime temperatures compared to S. Further, a WGCNA analysis and qRT-PCR verification revealed that these genes were mainly regulated by five transcription factors, WRKY20, MYB86, bHLH144, bHLH95, and NAC12, whose expression was also increased in O compared to S under LNT. These results allowed the elucidation of the probable molecular mechanism of oil accumulation under LNT conditions in the O cultivar. Subsequent biochemical assays verified that BnMYB86 transcriptionally activated BnLPP expression, contributing to oil accumulation. Meanwhile, at LNT, the expression levels of these genes in the O plants were higher than at high nighttime temperatures, DEGs (SUT, PGK, PK, GPDH, ACCase, SAD, KAS II, LACS, FAD2, FAD3, KCS, KAR, ECR, GPAT, LPAAT, PAP, DGAT, STERO) related to lipid biosynthesis were also upregulated, most of which are used in oil accumulation.