Cloning and Expression Analysis of a Farnesyl Diphosphate Synthase (FPPS) Gene from Chamaemelum nobile

Abstract

Farnesyl diphosphate synthase (FPPS), an isopentenyl transferase, catalyzes the condensation reaction of five carbon isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) to form fifteen carbon farnesyl pyrophosphate (FPP), which is the key precursor for sesquiterpene biosynthesis. In this study, a FPPS gene (CnFPPS) was cloned from Chamaemelum nobile. The full-length cDNA of CnFPPS is 1239 bp and contains an open reading frame (ORF) of 1029 bp encoding 342 amino acids. The theoretical molecular weight and pI of the CnFPPS protein are 39.38 kDa and 5.59, respectively. Multiple alignment analysis showed the protein sequence of CnFPPS had a high homology with FPPS proteins from other plants. The deduced amino acid of CnFPPS contained five conservative domains such as substrate binding pocket, substrate-Mg²⁺ binding site, catalytic site, aspartate-rich region 1 and 2, suggesting CnFPPS is one member of FPPS family in C. nobile. Phylogenetic analysis based on the amino acid sequences of FPPSs showed that CnFPPS was closely related to the FPPS of Matricaria chamomilla. The result of qRT-PCR revealed that CnFPPS gene was constitutively expressed in different tissues of C. nobile, with the highest expression in the root. These findings improve the understanding of the synthesis and regulation of the terpenoid compounds at the molecular level and lay a foundation for studying the regulatory functions of CnFPPS in terpenoid biosynthetic pathway in C. nobile.