Gu Xu, Yu Anmin, Li Ping, Zhang Meihong, Lv Ya, Xu Debing, Liu Aizhong
College of Forestry, Southwest Forestry University, Kunming 650224, China.
Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming 650224, China.
Int J Mol Sci. 2025 Jun 7;26(12):5465. doi: 10.3390/ijms26125465.
Oil-tea (), a typical oilseed tree, produces high-quality edible vegetable oils that contain rich unsaturated fatty acids and diverse lipid-soluble active compounds such as squalene. Although squalene biosynthesis and its molecular regulation have been studied in several plants, the molecular mechanisms underlying squalene biosynthesis in oil-tea seeds remain uncertain. We investigated and determined squalene accumulation with seed development. We conducted comparative transcriptomic analyses using the RNA-seq technique at the early, fast biosynthesis, and late stages of squalene accumulation with oil-tea seed development and identified 13 squalene biosynthesis key enzyme genes (such as , , , and ) in developing oil-tea seeds. According to whether the expressions of key enzyme genes were associated with squalene accumulation we found that the precursor IPP of squalene biosynthesis obtained via the MVA pathway was dominant with oil-tea seed development. Based on the gene co-expression analyses, we identified multiple transcription factors potentially involved in regulating squalene biosynthesis such as , , , and . Using yeast one-hybrid and dual-luciferase assay experiments we demonstrated that the transcription factor could activate the expression of a key enzyme gene , suggesting that might be a critical regulator during squalene biosynthesis in oil-tea seed development. This study gives not only insights into understanding the molecular basis of squalene biosynthesis in oil-tea developing seeds but also provides gene resources for developing genetically improved varieties with higher content of squalene in oil-tea.
油茶是一种典型的油料树种，能产出富含不饱和脂肪酸以及多种脂溶性活性化合物（如角鲨烯）的优质食用植物油。尽管已在多种植物中研究了角鲨烯的生物合成及其分子调控，但油茶种子中角鲨烯生物合成的分子机制仍不明确。我们研究并测定了角鲨烯在种子发育过程中的积累情况。利用RNA测序技术，我们对油茶种子发育过程中角鲨烯积累的早期、快速生物合成期和后期进行了比较转录组分析，鉴定出了13个在发育中的油茶种子里的角鲨烯生物合成关键酶基因（如、、、和）。根据关键酶基因的表达是否与角鲨烯积累相关，我们发现通过甲羟戊酸途径获得的角鲨烯生物合成前体异戊烯焦磷酸在油茶种子发育过程中占主导地位。基于基因共表达分析，我们鉴定出了多个可能参与调控角鲨烯生物合成的转录因子，如、、、和。通过酵母单杂交和双荧光素酶检测实验，我们证明转录因子能够激活关键酶基因的表达，这表明可能是油茶种子发育过程中角鲨烯生物合成的关键调节因子。本研究不仅有助于深入了解油茶发育种子中角鲨烯生物合成的分子基础，还为培育油茶角鲨烯含量更高的遗传改良品种提供了基因资源。
