The isopentenyl diphosphate isomerase (IPI) is considered to be a key enzyme involved in terpenoid biosynthesis pathway of Jatropha curcas. In order to study the expression and regulation of isopentenyl diphosphate isomerase (IPI) gene in the terpenoid biosynthesis pathway of Jatropha curcas, a 1536bp promoter fragment of IPI gene was cloned by PCR method. The bioinformatics analysis showed that the fragment contained the conserved promoter sequence, such as TATA-box, CAAT-box. Furthermore, it contained several elements related to auxin response, gibberellin response, disease-related and high temperature. To determine the optimal promoter sequence for gene expression, IPI gene promoter was deleted from its 5′ end to form promoter fragments with 283, 550, 970, 1276 and 1536bp. Such fragments were fused to a β-glucuronidase (GUS) gene. The fused genes were transformed into Nicotiana benthamiana using Agrobacterium tumefaciens-mediated method for transient expression. GUS quantitative fluorometric assays demonstrated that the five different length fragments of the promoter had promoter activities and the activities were increased with the deleted length of promoters.
