Thymol, as a dietary monoterpene, is a phenol derivative of cymene, which is the major component of the essential oil of Trachyspermum ammi (L.). It shows multiple biological activities: antifungal, antibacterial, antivirus and anti-inflammatory. T. ammi, commonly known as ajowan, belongs to Apiaceae and is an important medicinal seed spice. To identify the putative genes involved in thymol and other monoterpene biosynthesis, we provided transcriptomes of four inflorescence tissues of two ajowan ecotypes, containing different thymol yield. This study has detected the genes encoding enzymes for the go-between stages of the terpenoid biosynthesis pathways. A large number of unigenes, differentially expressed between four inflorescence tissues of two ajowan ecotypes, was revealed by a transcriptome analysis. Furthermore, differentially expressed unigenes encoding dehydrogenases, transcription factors, and cytochrome P450s, which might be associated with terpenoid diversity in T. ammi, were identified. The sequencing data obtained in this study formed a valuable repository of genetic information for an understanding of the formation of the main constituents of ajowan essential oil and functional analysis of thymol-specific genes. Comparative transcriptome analysis led to the development of new resources for a functional breeding of ajowan.

The essential oil chemotype of an Iranian ecotype of ajowan was identified using gas chromatography mass spectrometry (GC-MS) analysis. Fifteen chemical compounds of essential oils were identified using GC-MS analysis. Thymol, ρ-cymene and γ-terpinen were identified as major components in essential oil of investigated ecotype with 54.32, 21.74, and 19.38 percentages, respectively. Only 0.42 % of the decomposed essential oil was related to carvacrol. Based on the results of the present study, thymol was the predominant composition in the essential oil of investigated ecotype of ajowan and these results can help to purposeful use of this ecotype in pharmaceutical industry, traditional medicine, and other industries.

In an attempt to increase tolerance to salinity stress in tobacco plants, the genes encoding the mutant form of glutamyl kinase (proB), pyrroline-5-carboxylate synthetase, and osmotin were cloned into three different shuttle vectors and were separately introduced into the tobacco plants. The transgenic lines were compared for their ability to produce shoots and grow in MS medium containing 320 mM NaCl; it was shown that the transgenic lines containing genetically handled osmotin gene are more resistant to salinity. The amount of chlorophyll a was used to show continuing growth of plant lines. The results showed that only the tobacco lines transformed with the modified osmotin gene exhibited greater tolerance to salinity.

Indian ginseng (Withania somnifera) is a plant adapted to the climatic conditions of the southern regions of Iran. One of the important methods to increase secondary metabolites in medicinal plants is hairy root culture. Hairy roots are genetically stable and able to increase metabolites without using hormones. In order to increase ...