Expression of Genes Involved in the Biosynthesis of Crocin and Safranal in Cell Suspension Culture of Saffron (Crocus sativus)

Saffron possesses important medicinal properties, all of which are due to the secondary metabolites such as crocin, picrocrocin, and safranal. This study aims at investigating biosynthesis of the secondary metabolites during growth of saffron callus cells in a suspension culture, and examining the expression of genes controlling the metabolites. Sterilized saffron corms were cultured in a MS½ medium supplemented by 2-4-D and BAP. The calluses were induced after fourteen days, and then put into the suspension culture after being four times subcultured. From the 8th to 14th day after establishment of the suspension culture, the amount of secondary metabolites was measured by HPLC, and gene expressions were analyzed with real-time PCR for three samples taken once a day at the same time from the suspension. It was found that the amount of secondary metabolites and expression of the corresponding genes ( CsLYC , CsBCH and CsGT 2 ) were saturated on the 12th day after establishment of the suspension. For the most effective stimulation of genes and biosynthesis of apocarotenoids, suitable elicitors and precursors should be added within 72 h before saturation of the synthesis rate which happens on the 12th day after establishment of the suspension.