Differential gene expression analysis of alkaloids production pathway in Catharanthus roseus following Salicylic acid treatment

Background and Aim: Madagascar periwinkle (Catharanthus roseus), an important medicinal and ornamental plant, produces a wide range of terpenoid indole alkaloids, including vinblastine and vincristine alkaloids which are extensively used for cancer treatments. Periwinkle is the only source of vinblastine and vincristine sulfate drugs, but the low production rate is a major challenge for the pharmaceutical industry. Furthermore, vinblastine and vincristine are synthesized in complex pathways that are affected by a diverse group of elicitors such as Salicylic acid (SA). The purpose of this study was to investigate the effect of foliar application of SA on the expression pattern of some of the Terpenoid indole alkaloid (TIA) pathway genes using the Real- time PCR method.Methods: Foliar spraying of SA (۰.۰۱ mM) was used and samples were taken at ۰, ۱۲, ۱۸, ۲۴ and ۴۸ hours after treatment. Real-time PCR was used to investigate the expression pattern of Chorismate mutase (CM), Tryptophan decarboxylase (TDC) and Deacetylvindoline-۴-O-acetyltransferase (DAT) genes, following SA treatment.Results: The results of this experiment showed that CM gene expression was decreased, but not significantly. Furthermore, the transcript levels of TDC and DAT genes were significantly up-regulated and the highest level was observed after ۴۸ hours post SA treatment.Conclusion: Real- time PCR results suggests that SA induces transcription of major genes involved in alkaloids biosynthesis in Catharanthus roseus. Although, the rate of alkaloids production has not yet been measured, it can be concluded that up-regulation of TDC and DAT genes may result in a higher production rate of vinblastine and vincristine alkaloids.

Keywords:

Catharanthus roseus , Salicylic acid , Terpenoid indole alkaloid , Real- time PCR