Cloning and Expression Analysis of Two Dehydrodolichyl Diphosphate Synthase Genes from Tripterygium wilfordii

Objective: To clone and investigate two dehydrodolichyl diphosphate synthase genes of Tripterygium wilfordii by bioinformatics and tissue expression analysis. Materials and Methods: According to the T. wifordii transcriptome database, specific primers were designed to clone the TwDHDDS1 and TwDHDDS2 genes via PCR. Based on the cloned sequences, protein structure prediction, multiple sequence alignment and phylogenetic tree construction were performed. The expression levels of the genes in different tissues of T. wilfordii were measured by real?time quantitative PCR. Results: The TwDHDDS1 gene encompassed a 873 bp open reading frame(ORF) and encoded a protein of 290 amino acids. The calculated molecular weight of the translated protein was about 33.46 kDa, and the theoretical isoelectric point(pI) was 8.67. The TwDHDDS2 encompassed a 768 bp ORF, encoding a protein of 255 amino acids with a calculated molecular weight of about 21.19 kDa, and a theoretical isoelectric point(pI) of 7.72. Plant tissue expression analysis indicated that TwD HDDS1 and TwDHDDS2 both have relatively ubiquitous expression in all sampled organ tissues, but showed the highest transcription levels in the stems. Conclusions: The results of this study provide a basis for further functional studies of TwDHDDS1 and TwDHDDS2. Most importantly, these genes are promising genetic targets for the regulation of the biosynthetic pathways of important bioactive terpenoids such as triptolide.