Identification of Genes Involved in Celastrol Biosynthesis by Comparative Transcriptome Analysis in Tripterygium wilfordii

Tripterygium wilfordii has been renowned mostly because of the anticancer effects of its root extracts, which is partly ascribed to the presence of celastrol, a pentacyclic triterpenoid, as one of the main active components. Celastrol also has recently been reported as an effective prodrug in the treatment of obesity. Despite the promising activities, the pathway leading to celastrol biosynthesis, especially cytochrome P450 (CYP) enzyme(s) that occur in its downstream steps, are largely unknown. This study conducted a comparative analysis of the T. wilfordii transcriptome derived from its root and leaf tissues. Differential gene expression analysis identified a number of root-specific CYP genes. Further phylogenetic analysis suggested specific family members of CYPs that may participate in the late steps during celastrol biosynthesis. Root-specific transcription factors (TFs) that may play regulatory roles in celastrol biosynthesis were also discussed. This genetic resource will aid in isolating the celastrol biosynthetic genes as well as engineering the celastrol biosynthesis pathway.