Abstract：
The precise biological function and activity of the deoxylulose-5-phosphate reductoisomerase (DXR) gene and its promoter in Osmanthus fragrans var. semperflorens remain unclear, even though OfDXR is known as the crucial enzyme involved in plant terpenoid synthesis. This study aimed to shed light on the role and activity of the OfDXR gene and its promoter in O. fragrans var. semperflorens by employing RACE-PCR and Hi-TAIL-PCR techniques for the cloning of the gene and promoter sequence from the petal tissue. Subsequently, genetic transformation and histochemical staining methods were utilized to analyze their function and activity. The OfDXR gene exhibited a DNA sequence length of 5241 bp, encompassing 12 exons and 11 introns. The corresponding cDNA sequence of the OfDXR gene was 1629 bp, encoding 474 amino acid residues. Expression analysis revealed that the OfDXR gene was predominantly active in the petals during the early full blooming stage. Overexpression of the OfDXR gene in Arabidopsis plants at the primary or full blooming stage led to an augmentation in the total terpenoid content. Furthermore, the promoter sequence of the OfDXR gene spanned a length of 1174 bp and contained conserved regulatory/response elements, demonstrating functional activity. These findings indicate that the OfDXR gene plays a pivotal role in terpenoid synthesis, while its promoter exhibits robust activity.
摘要：
桂花中脱氧葡萄糖-5-磷酸还原异构酶（DXR）基因及其启动子的精确生物学功能和活性。semperflorens还不清楚,尽管OfDXR被认为是参与植物萜类合成的关键酶。本研究旨在阐明OfDXR基因及其启动子在O.fragransvar中的作用和活性。semperflorens通过使用RACE-PCR和Hi-TAIL-PCR技术从花瓣组织中克隆基因和启动子序列。随后，利用遗传转化和组织化学染色方法分析其功能和活性。OfDXR基因的DNA序列长度为5241bp,包含12个外显子和11个内含子。OfDXR基因的相应cDNA序列为1629bp,编码474个氨基酸残基。表达分析显示，OfDXR基因在盛开的早期阶段主要在花瓣中活跃。在初生或盛开阶段，拟南芥植物中OfDXR基因的过表达导致总萜类含量增加。此外，OfDXR基因的启动子序列跨越1174bp的长度，含有保守的调节/反应元件，展示功能活动。这些发现表明OfDXR基因在萜类化合物合成中起着关键作用,而其启动子表现出强大的活性。
