Overexpression of chrysanthemyl diphosphate synthase (CDS) gene in Tagetes erecta leads to the overproduction of pyrethrin

Abstract

Pyrethrins are widely accepted as natural insecticides and offers several advantages of synthetic compounds, i.e., rapidity of action, bioactivity against a wide range of insects, comparatively lesser costs and the like. A significant source of pyrethrin is Chrysanthemum cinerariaefolium; cultivated in restricted areas, as a result; natural pyrethrins are not produced in a large amount that would meet the ongoing global market demand. However, increasing its content and harnessing the desired molecule did not attract much attention. To enhance the production of pyrethrins in Tagetes erecta, the Chrysanthemyl diphosphate synthase (CDS) gene was overexpressed under the promoter CaMV35S. Hypocotyls were used as explant for transformation, and direct regeneration was achieved on MS medium with 1.5 mg L^-1 BAP and 5.0 mg L^-1 GA3. Putative transgenics were screened on 10 mgL^-1 hygromycin. After successful regeneration, screening and rooting process, the transgenic plants were raised inside the glass house and PCR amplification of CDS and HYG-II was used to confirm the transformation. Biochemical analysis using HPLC demonstrated the expression levels of the pyrethrin, which was approx. twenty-six fold higher than the non-transformed Tagetes plant.

Keywords: Agrobacterium tumefaciens; Chrysanthemum cinerariaefolium; Chrysanthemyl diphosphate synthase; Overexpression; Pyrethrins; Tagetes erecta.