College of Tropical Crops, Sanya Nanfan Research Institute, Hainan University, Hainan 570228, China.
College of Tropical Crops, Sanya Nanfan Research Institute, Hainan University, Hainan 570228, China; Rubber Research Institute of Chinese Academy of Tropical Agricultural Sciences (CATAS), China.
Plant Sci. 2022 Aug;321:111317. doi: 10.1016/j.plantsci.2022.111317. Epub 2022 May 21.
Oil palm (Elaeis guineensis Jacq.) is one of the most important oil crops in the world, and compared to all oil crops, it has the highest productive efficiency. In the present study, a MADS-box transcription factor of the AGAMOUS class, named EgAGL9, was identified by expression profile analysis in the different developmental stages of oil palm mesocarp. Real-time quantitative PCR results confirmed that the expression of EgAGL9 increased rapidly during the last stages of oil palm mesocarp development. Then, three downstream genes, including EgSAD (Stearoyl-ACP desaturase), EgTSA (Tryptophan synthase) and EgSDH (Succinate dehydrogenase), were screened by ChIP-Seq and data analysis. EMSA analysis verified that EgAGL9 interacted with the promoter regions of EgSAD, EgTSA and EgSDH. Moreover, the expression levels of EgSAD, EgTSA and EgSDH were downregulated in EgAGL9-overexpressing protoplasts and calli of oil palm. Compared to WT, the total lipid content and ratio of unsaturated fatty acids in transgenic calli (including oleic acid, linoleic acid and linolenic acid) were significantly decreased. Together, these results revealed that these three EgAGL9-regulated genes are involved in regulatory pathways in the oil palm mesocarp. Compared with previous studies, the present study provides a new research strategy for understanding of the molecular regulatory pathways of lipid metabolism in mesocarp of oil palm. The obtained results will bring a new perspective for a comprehensive understanding of the regulation of the metabolic accumulation in the oil palm mesocarp.
油棕（Elaeis guineensis Jacq.）是世界上最重要的油料作物之一，与所有油料作物相比，它具有最高的生产效率。在本研究中，通过油棕中果皮不同发育阶段的表达谱分析，鉴定了一个 AGAMOUS 类的 MADS 框转录因子，命名为 EgAGL9。实时定量 PCR 结果证实，EgAGL9 的表达在油棕中果皮发育的最后阶段迅速增加。然后，通过 ChIP-Seq 和数据分析筛选了三个下游基因，包括 EgSAD（硬脂酰-ACP 去饱和酶）、EgTSA（色氨酸合酶）和 EgSDH（琥珀酸脱氢酶）。EMSA 分析验证了 EgAGL9 与 EgSAD、EgTSA 和 EgSDH 的启动子区域相互作用。此外，EgAGL9 过表达的油棕原生质体和愈伤组织中 EgSAD、EgTSA 和 EgSDH 的表达水平下调。与 WT 相比，转基因愈伤组织中的总脂质含量和不饱和脂肪酸比例（包括油酸、亚油酸和亚麻酸）显著降低。综上所述，这些结果表明这三个 EgAGL9 调控的基因参与了油棕中果皮的调控途径。与以前的研究相比，本研究为理解油棕中果皮脂质代谢的分子调控途径提供了新的研究策略。研究结果将为全面理解油棕中果皮代谢积累的调控提供新的视角。
