Cloning and analysis of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase genes HsHDR1 and HsHDR2 in Huperzia serrate

We cloned and analyzed the two genes of the 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase(HDR) gene family from Huperzia serrate.The two transcripts coding HDR,named Hs HDR1 and Hs HDR2,were discovered in the transcriptome dataset of H.serrate and were cloned by reverse transcription-polymerase chain reaction(RT-PCR).The physicochemical properties,protein domains,protein secondary structure,and 3D structure of the putative Hs HDR1 and Hs HDR2 proteins were analyzed.The full-length c DNA of the Hs HDR1 gene contained 1431 bp encoding a putative protein with 476 amino acids,whereas the Hs HDR2 gene contained 1428 bp encoding a putative protein of 475 amino acids.These two proteins contained the conserved domain of 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate reductase(PF02401),but without the transmembrane region and signal peptide.The most abundant expression of Hs HDR1 and Hs HDR2 was detected in H.serrate roots,followed by the stems and leaves.Our results provide a foundation for exploring the function of Hs HDR1 and Hs HDR2 in terpenoid and sterol biosynthesis in Huperziaceae plants.

过表达HDR和ADS基因对青蒿素生物合成的影响

青蒿素是从草本药用植物黄花蒿(Artemisia annua L.)中分离提取的一种含有过氧桥基团结构的新型倍半萜内酯,它是世界卫生组织推荐治疗脑型疟疾和抗氯喹恶性疟疾的特效药物。本研究采用过表达青蒿素生物合成途径中关键酶基因的方法,培育出青蒿素含量提高的转基因黄花蒿。采用根癌农杆菌介导遗传转化方法,潮霉素抗性筛选获得同时转化HDR和ADS两个基因的转基因黄花蒿;通过基因组PCR检测确认获得了6个共转化HDR和ADS基因的转基因株系。实时荧光定量PCR检测基因表达量,结果表明转基因株系中HDR和ADS基因表达量均高于非转基因植株(仅ah3株系ADS基因表达量没有显著性提高);HPLC测定青蒿素含量结果表明转基因株系中青蒿素含量均高于非转基因植株。青蒿素含量最高的转基因株系ah70中青蒿素含量为非转基因对照的3.48倍。本研究实验结果表明,过表达HDR和ADS基因在黄花蒿的代谢途径中具有提高青蒿素含量的作用,为进一步利用代谢工程技术培育青蒿素高产转基因黄花蒿提供了良好基础。