Collaborative Innovation Centre of Sustainable Forestry in Southern China, College of Forest Science, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China.
State Forestry and Grassland Administration Key Laboratory of Silviculture in Downstream Areas of the Yellow River, College of Forestry, Shandong Agricultural University, Tai'an 271018, China.
Int J Mol Sci. 2022 Aug 10;23(16):8897. doi: 10.3390/ijms23168897.
, whose seeds are rich in unsaturated fatty acids (UFAs), is a high oil value tree species, and the seed oil has perfect biodiesel properties. Therefore, the elucidation of the effect of 24-epibrassinolide (EBL) on fatty acid (FA) concentration and the expression of FA biosynthesis-related genes is critical for deeply studying the seed oil in . In this study, we aimed to investigate the changing trend of FA concentration and composition and identify candidate genes involved in FA biosynthesis under EBL treatment using transcriptome sequencing and GC-MS. The results showed that 5 μmol/L of EBL (EBL5) boosted the accumulation of FA and had the hugest effect on FA concentration at 70 days after flowering (DAF). A total of 20 FAs were identified; among them, palmitic acid, oleic acid, linoleic acid, and linolenic acid were the main components. In total, 117,904 unigenes were detected, and the average length was 1120 bp. Among them, 1205 unigenes were assigned to 'lipid translations and metabolism' in COG categories, while 290 unigenes were assigned to 'biosynthesis of unsaturated fatty acid' in KEGG categories. Twelve important genes related to FA biosynthesis were identified, and their expression levels were confirmed by quantitative real-time PCR. , , and , encoding FA biosynthesis-related enzymes, all expressed the highest at 70 DAF, which was coincident with a rapid rise in FA concentration during seed development. and conduced to UFA and saturated fatty acids (SFA) accumulation, respectively. EBL5 induced the expression of FA biosynthesis-related genes. The concentration of FA was increased after EBL5 application, and EBL5 also enhanced the enzyme activity by promoting the expression of genes related to FA biosynthesis. Our research could provide a reference for understanding the FA biosynthesis of seeds at physiological and molecular levels.
，其种子富含不饱和脂肪酸（UFAs），是一种高油价值的树种，种子油具有完美的生物柴油特性。因此，阐明 24-表油菜素内酯（EBL）对脂肪酸（FA）浓度的影响以及与 FA 生物合成相关的基因表达对于深入研究种子油至关重要。在这项研究中，我们旨在通过转录组测序和 GC-MS 研究 EBL 处理下 FA 浓度和组成的变化趋势，并鉴定参与 FA 生物合成的候选基因。结果表明，5 μmol/L 的 EBL（EBL5）促进了 FA 的积累，对开花后 70 天（DAF）的 FA 浓度影响最大。共鉴定出 20 种 FA；其中，棕榈酸、油酸、亚油酸和亚麻酸是主要成分。共检测到 117904 条 unigenes，平均长度为 1120bp。其中，1205 条 unigenes在 COG 类别中被分配到“脂质翻译和代谢”，而 290 条 unigenes在 KEGG 类别中被分配到“不饱和脂肪酸的生物合成”。鉴定出 12 个与 FA 生物合成相关的重要基因，并通过定量实时 PCR 确认其表达水平。编码 FA 生物合成相关酶的 、 、 和 ，在种子发育过程中 FA 浓度快速上升时，在 70 DAF 时表达最高。 和 分别促进了 UFA 和饱和脂肪酸（SFA）的积累。EBL5 诱导 FA 生物合成相关基因的表达。EBL5 应用后 FA 浓度增加，EBL5 通过促进 FA 生物合成相关基因的表达增强了酶活性。我们的研究可以为理解种子中 FA 的生物合成提供生理和分子水平的参考。
