The impact of temperature on metabolites and the expression of genes involved in thymol and carvacrol biosynthesis pathway in Thymus vulgaris

Environmental factors make changes in the amount and type of secondary metabolites. To study the effects of temperature regimes on secondary metabolites and the expression of genes involved in biosynthesis pathway of thymol and carvacrol in thyme, an experiment was conducted in a growth chamber for one month with three thermal treatments including heat, cold and normal temperatures. Essential oil compounds were measured by Gc / MS and Gc and the expression of TvTps1, CYP178 and CYP180 genes assayed by qRT-PCR. Both heat and cold temperatures increased the phenolic monoterpen compounds (thymol and carvacrol) compared to normal condition. High temperature led to significant increases in carvacrol while low temperature resulted in a great increase in the amount of thymol. Gamaterpenin level was declined due to thermal treatments. Gene expression analysis revealed that the cold condition increased the expression of TvTps1 and CYP178 genes, while heat decreased the expressions. CYP180 and CYP181 were highly expressed under both cold and heat conditions, although the amount of expression was much higher under high temperature. Generally, the results indicated that the environment temperature played a key role in thyme metabolites type and content. It could be concluded that the regions with high and low temperatures were suitable for carvacrol and thymol production, respectively.