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Feverfew (Tanacetum partheniumL. Schulz Bip.) is a medicinal herb belonging to the Asteraceae which recently raised researcher’s attention due to its medicinal value and pharmacological activities, especially as a migraine prophylaxis agent and also for treatment of cancer. Parthenolide has a sesquiterpene lactone structure which is most likely synthesized through the mevalonic acid (MVA) pathway. Recently, it has been shown that there is cross a talk between the MVA and the MEP pathways through IDP (Iosopentenyl diphosphate) exchange as a precursor for the biosynthesis of different terpenes hence, parthenolide biosynthesis could be affected by the MEP pathway as well. In the present work, the relative gene expression of two key genes of the MVA pathway, including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and germacrene A synthase (GAS) and two key genes of the MEP pathway including 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) and hydroxy-2-methyl-2-(E)-butenyl4-diphosphate reductase (HDR) were examined in leaves derived from the vegetative or generative phases, also in flowers using real time PCR. The results of our study showed that expression of these genes depend on the growth stage and genotype. Moreover, in which in the flowers and leaves derived from vegetative phase in different genotypes only the TpGAS gene expression showed a significant difference, while in the leaves derived of generative phase the relative gene expression showed a significant difference for TpHMGR, TpGAS and TpDXR.

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Peppermint (Mentha piperita L., Lamiaceae) is one of the most important medicinal and aromatic plants. Menthol is the major monoterpene constituent of peppermint’s essential oil, which is used for pharmaceuticals, cosmetics and food industries. This work was aimed to study the expression pattern of important genes (Pr, Mfs, Ls) in menthol biosynthesis pathway in different plant’s organs (leaf, flower and stem) at the beginning of flowering stage. The peppermint plants were supplied from Iranian Institute of Medicinal Plants and were transferred into a greenhouse in pots. Analysis of variance showed that there is a significant difference between leaf, flower and stem, with respect to mRNA transcript level. The results of this study indicated that the level of gene expression of Pr, Mfs and Ls were altered in the different organs. There are direct relationship between the content of menthone and menthofuran and level of gene expressions of Pr and Mfs genes in flower and leaf respectively. It can be concluded that probably the expression of Mfs and Pr genes in these organs may be regulated at transcriptional level.