Sterols are secondary metabolites commonly found in rapeseed that play crucial physiological roles in plants and also benefit human health. Consequently, unraveling the genetic basis of sterol synthesis in rapeseed is highly important. In this study, 21 individual sterols, as well as total sterol content (TS) were detected in a double haploid (DH) population of Brassica napus, and a total of 24 QTL and 157 mQTL were identified that were associated with TS and different individual sterols. Time-series transcriptomic analysis showed that the differentially expressed genes (DEGs) involved in sterol and lipid biosynthesis pathways were enriched. Additionally, a regulatory network between sterol-related DEGs and transcription factors (TFs) was established using coexpression analysis. Some candidate genes were identified with the integration of transcriptomic analysis and QTL mapping, and the key candidate gene BnSQS1.C03 was selected for further functional analysis. BnSQS1.C03 demonstrated squalene synthase activity in vitro and increased the TS by 3.8% when overexpressed in Arabidopsis. The present results provide new insights into sterol regulatory pathways and a valuable genetic basis for breeding rapeseed varieties with high sterol content in the future.

中文翻译：

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整合 QTL 作图和转录组学来破译甘蓝型油菜甾醇代谢的遗传结构


甾醇是油菜籽中常见的次生代谢产物，在植物中发挥着重要的生理作用，也有益于人类健康。因此，解开油菜籽甾醇合成的遗传基础非常重要。本研究在甘蓝型油菜双单倍体(DH)群体中检测到21个个体甾醇以及总甾醇含量(TS)，并鉴定出与TS和不同个体相关的总共24个QTL和157个mQTL。甾醇。时间序列转录组分析表明，参与甾醇和脂质生物合成途径的差异表达基因（DEG）丰富。此外，利用共表达分析建立了甾醇相关 DEG 和转录因子 (TF) 之间的调控网络。通过转录组分析和QTL定位相结合，鉴定了部分候选基因，并选择关键候选基因BnSQS1.C03进行进一步的功能分析。 BnSQS1.C03 在体外表现出角鲨烯合酶活性，并且在拟南芥中过表达时，TS 增加了 3.8%。本研究结果为甾醇调控途径提供了新的见解，并为未来选育高甾醇含量油菜品种提供了宝贵的遗传基础。