目的 克隆鱼腥草3-羟基-3-甲基戊二酰辅酶A还原酶（HMGR）基因并分析其差异表达。方法 采用实时荧光定量PCR（RT-PCR）方法获得HMGR基因cDNA序列并对HMGR蛋白进行理化性质、蛋白二级结构及三维结构预测分析，并预测该蛋白功能；利用RT-PCR方法检测HMGR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HMGR基因cDNA全长为1 626 bp，编码541个氨基酸。生物信息学预测HMGR蛋白含2个跨膜区，不含信号肽。HMGR基因主要在鱼腥草的花中表达，其他器官中表达相对较低，地下茎中表达量最低。结论 首次从鱼腥草中克隆了HMGR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作用奠定基础。

Objective To clone and analyze the expression difference sequence of 3-hydroxy-3-methylglutaryl coenzyme A redutase (HMGR) gene from Houttuynia cordata. Methods The sequence of HMGR was cloned from H. cordata by RT-PCR strategy. The physical and chemical properties, secondary structure, and three-dimensional structure of the HMGR protein were forecasted and analyzed, and its structure and function were predicted. And the different expression of HMGR gene in rhizome, stems, leaves, and flowers were analyzed by fluorescent quantitative PCR. Results The cDNA contained a 1 626 bp open reading frame and encoded a predicted protein of 541 amino acids. Two transmembrane regions and no signal peptide were present in HMGR. Relative real-time PCR analysis indicated that HMGR showed the highest transcript abundance in the flowers, and the lowest levels in the rhizomes. Conclusion This study cloned and expression analyzed HMGR gene from H. cordata for the first time. The result will provide a foundation for exploring the mechanism of terpenoid biosynthesis in H. cordata.

国家自然科学基金项目（30870230）；湖南省科技计划项目（2013FJ6090，2014FJ4207）；湖南省高校创新平台开放基金项目（15K100）；湖南省生物类专业大学生创新训练中心资助及植物学湖南省高校"十二五"重点建设学科资助（ZWX2016-07）