Cui Yaqi, Ma Jiacheng, Jiao Mengying, Zhao Xueying, Ding Jingwen, Feng Chenran, Liu Peng, Long Yuehong, Xing Zhaobin
College of Life Sciences, North China University of Science and Technology, Tangshan 063210, China.
Hortic Res. 2025 May 21;12(8):uhaf133. doi: 10.1093/hr/uhaf133. eCollection 2025 Aug.
Oleanane-type triterpenoid saponins are the primary medicinal components of . During saponin biosynthesis in , various members of the 2,3-oxidosqualene cyclase (OSC) gene family can direct 2,3-oxidosqualene into triterpene saponin and sterol synthesis pathways. However, the precise molecular mechanism underlying this phenomenon remains unclear. We initially screened for β-amyrin synthase 1 (bAS1) and cycloartenol synthase 1 (CAS1) among 10 genes using genome-wide identification and correlation analysis. Subcellular localization, catalytic experiments, and transient overexpression demonstrated that bAS1 and CAS1 catalyze the formation of the triterpene skeleton β-amyrin and sterol precursor cycloartenol exclusively in the cytoplasm, enhancing and inhibiting the biosynthesis of oleanane-type saponins, respectively. Results from site-directed mutagenesis and molecular docking indicated that W-WY and Y-WH triplets characterized the active sites of , respectively. GUS (β-glucuronidase) staining and electrophoretic mobility shift assay (EMSA) experiments on the promoter region revealed that various colored light quality, DNA methylation, and five transcription factors (NAC047, NAC098, WRKY40, MYB4, and ERF66) regulated the expression of and . This study provides preliminary insights into the molecular mechanisms by which and regulate saponin synthesis in .
齐墩果烷型三萜皂苷是[植物名称]的主要药用成分。在[植物名称]皂苷生物合成过程中，2,3-氧化鲨烯环化酶（OSC）基因家族的不同成员可将2,3-氧化鲨烯引导至三萜皂苷和甾醇合成途径。然而，这一现象背后的确切分子机制仍不清楚。我们最初通过全基因组鉴定和相关性分析，在10个[基因名称]中筛选出β-香树脂醇合酶1（bAS1）和环阿屯醇合酶1（CAS1）。亚细胞定位、催化实验和瞬时过表达表明，bAS1和CAS1仅在细胞质中催化三萜骨架β-香树脂醇和甾醇前体环阿屯醇的形成，分别增强和抑制齐墩果烷型皂苷的生物合成。定点诱变和分子对接结果表明，W-WY和Y-WH三联体分别表征了[酶名称]的活性位点。对启动子区域进行的GUS（β-葡萄糖醛酸酶）染色和电泳迁移率变动分析（EMSA）实验表明，各种颜色光质、DNA甲基化以及五个转录因子（NAC047、NAC098、WRKY40、MYB4和ERF66）调控了[基因名称]和[基因名称]的表达。本研究为[植物名称]中[基因名称]和[基因名称]调控皂苷合成的分子机制提供了初步见解。
