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.