Cloning and functional analysis of farnesyl diphosphate synthase (FPPS) gene from Mylabris cichorii Cloning, functional analysis of McFPPS.

Cantharidin, a defensive terpene compound synthesized by the meloid beetle (Coleoptera, Meloidae), is an important anti-cancer agent. However, there has been little study done on how this compound synthesized by the beetle. In this paper, a farnesyl-diphosphate synthase gene, designated McFPPS, was isolated from Mylabris cichorii by RT-PCR based on conserved domains in other organisms. Multiple alignment analysis showed that the deduced amino acids shared >70% homology with FPPSs from other species and contained typically seven conservative regions. Expression profile analysis revealed that McFPPS was expressed throughout the tested growth stages of M. cichorii adults; whereas the transcripts accumulated to the highest level at 20 d male adults while the highest expression level appeared at 15 d females. Tissue expression pattern analysis showed McFPPS was expressed constitutively in all tested tissues and a relatively higher expression level in the alimentary canal of males, but no significant tissue difference in the females. For the first time, a RNA interference strategy was employed to induce a greater suppression of McFPPS mRNA, and thus, a sharp decrease in the expression levels of downstream genes and the concentration of product. All these results indicated McFPPS may be directly involved or play an essential role in the biosynthesis of cantharidin. This article is protected by copyright. All rights reserved