Effect of Abscisic Acid (ABA) on Crocin and Safranal Contents and Expression of Controlling Genes in Saffron (Crocus sativus L.)

Saffron (Crocus sativus L.) with unique flavor, aroma and color has many medicinal properties, in addition to foodstuffs. The present study aims to evaluate the effect of abscisic acid on Crocin and Safranal contents and expression of their controlling genes in saffron. Sterilized explants from saffron corms were cultured in a ½MS medium supplemented with 0.1 mg l-1 2-4-D and 0.5 mg l-1 BAP. The calluses were induced after fourteen days. After four times subculture and obtaining optimum growth conditions calluses were transferred into the suspension culture and treated with 0.5 and 1.5 mg l-1 abscisic acid. The samples were collected at 24 and 72 hours after treatment in three replications. Measurement of secondary metabolites safranal and crocin was done using HPLC method and expression analysis of CsLYC, CsGT-2 and CsBCH genes were made with real time PCR. The results showed that 24 and 72 hours after treatment with 0.5 and 1.5 mg l-1 of abscisic acid, the two CsLYC and CsGT-2 genes significantly showed increased expression. However, there was no significant difference in expression of CsBCH gene. Also, safranal and crocin contents were affected by treatment with abscisic acid at both sampling times and safranal and crocin amount were the highest at 72 hours after treatment with 1.5 mg l-1 of abscisic acid.