目的 克隆鱼腥草1-脱氧-D-木酮糖-5-磷酸还原异构酶(DXR)基因,并分析其差异表达.方法 采用RT-PCR方法获得DXR基因cDNA序列,并对DXR蛋白进行理化性质、蛋白二级结构及三维结构预测分析,并预测了该蛋白功能;利用实时荧光定量PCR方法检测了DXR基因在鱼腥草的地下茎、地上茎、叶、花中的表达情况.结果 克隆获得的DXR基因长为1 416 bp,编码471个氨基酸.生物信息学预测DXR蛋白不含跨膜区,不含信号肽.DXR基因在鱼腥草的叶片中表达丰度最高,其次是地下茎,再次是地上茎,花中表达量最低.结论 首次从鱼腥草中克隆了DXR基因,为进一步阐明该基因在鱼腥草萜类化合物代谢途径中的重要作用奠定基础.

Objective To clone the 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) gene from Houttuynia cordata and analyze the differential expression. Methods The cDNA sequence of DXR was cloned from H. cordata by using RT-PCR strategy. The physical and chemical properties, secondary structure, and three-dimensional structure of the DXR protein were forecasted and analyzed, and its function was predicted. The differential expression of DXR gene in rhizome, stems, leaves, and flowers was analyzed by fluorescent quantitative PCR. Results The cDNA contained a 1 416 bp open reading frame and encoded a predicted protein of 471 amino acids. Bioinformatics predicted that no transmembrane region and signal peptide were present in DXR. Relative real-time PCR analysis indicated that DXR showed the highest transcript abundance in leaves, moderate level in rhizomes, lower level in stems, and the lowest level in flowers. Conclusion This study clones DXR gene from H. cordata for the first time, and provides a foundation for exploring the mechanism of this gene for the terpenoid biosynthesis in H. cordata.

国家自然科学基金资助项目(30870230);湖南省高校创新平台开放基金项目(12K132);湖南省科技计划重点项目(2013FJ6090);湖南省科技计划项目湘西科技开发专项(2014FJ4207)