Expression of Genes Involved in Rosmarinic Acid Biosynthesis Pathway in Dragonhead Affected by Nanoparticles

In order to study the effect of titanium dioxide (TiO2) nanoparticle spraying on the expression of three genes RAS، PAL and TAT involved in the biosynthesis of rosmarinic acid in Dragonhead، this nanoparticle was sprayed on the plants at the initial flowering stage at different concentrations (0، 10، 20، 30 and 50 ppm) in a completely randomized design with three replications. Plant seeds were cultivated in a greenhouse under controlled conditions. The experiment was carried out at University College of Agriculture، Tehran University. Twenty-four hours after treatment، leaf samples were taken from the different treated and control plants in three biological replicates at complete flowering stage، and kept at -80° C for further analysis. The samples were dried in the shade for a week for extraction. High-performance liquid chromatography was used for determination of rosmarinic acid. The results showed a significant increase in the amount of rosmarinic acid when compared to the controls by which the content increased to 16. 78 mg/g extraction in concentration of 30ppm nanoparticle. The results of the expression pattern of the genes by qRT-PCR revealed that both RAS and PAL showed a similar behavior in all treatments although RAS was expressed more. TAT did not show a known pattern. It is noticeable that 30ppm nanoparticle was effective for gene expression and also to elevate the rate of rosmarinic acid biosynthesis.