Document Type : Research Paper

Author

• Mohammad Abyari

Department of Science, Farhanghiyan University, Tehran, Iran

Abstract

Thyme has attracted the attention of researchers because of its antioxidant, antimicrobial, and anticancer properties, which are due to some active compounds such as thymol and carvacrol. Elicitors are recognized as a potential tool for increasing valuable secondary metabolites. Therefore, this study was carried out to determining the effect of UV-B and salicylic acid on the biosynthesis pathway of thymol and carvacrol, and to understanding its molecular mechanism. To perform the experiment, thyme seeds were planted in plastic pots under greenhouse conditions in a completely randomized design with three replications. Seedlings were simultaneously sprayed by 1 mM salicylic acid and irradiated by UV-B. The results showed that the expressions of DXR, GTS, CYP178, and CYP180 genes were significantly increased after 24 h of treatment. This increase was greater in the simultaneous use of both elicitors, indicating the combined effect of salicylic acid and UV-B. After 48 and 72 h of treatment, the expressions of genes involved in the biosynthesis of thymol and carvacrol were decreased, indicating the plant's use of defense mechanisms to alleviate the symptoms of stress caused by the salicylic acid signaling pathway. Assay of thymol and carvacrol metabolites supported the results of gene expression. In general, it can be concluded that the highest expression levels of thymol and carvacrol biosynthetic genes and their metabolic content in thyme can be achieved 24 h after simultaneous treatment by salicylic acid and UV-B.

Keywords

• Thyme
• salicylic acid
• UV-B
• carvacrol
• thymol

Main Subjects

• Biotechnology