The effect of zinc nanochlate on vegetative characteristics and expression of genes affecting synthesis on thymol and carvacrol in Thymus (Thymus vulgaris)

This study aimed to investigate the effect of zinc nano-chelate on vegetative characteristics and expression of genes affecting the synthesis of thymol and carvacrol in thyme. The experimental design was factorial in a completely randomized design with three replications. The first factor included two cultivars of thyme and the second factor was the foliar application of zinc nano-chelate at four levels (zero (control), 2.5, 3.5, and 4.5 mg/l). The results of the present study showed that the highest content of carotenoids was at the level of 4.5 mg /l and the highest content of caracrol essential oil was at the level of 2.5 mg /l nano-zinc chelate. The results of comparing the mean of interaction treatments also showed that both cultivars showed the highest plant dry yield, chlorophyll a and b content in response to spraying of 3.5 mg /l nano-zinc chelate. In this study, the highest thymol content of essential oil was recorded in the levels of 2.5 and 3.5 mg/l  for Thymus vulgaris cultivars and Thymus Dena cultivars at the levels of 2.5 and 4.5 mg / L. The results showed that the effect of nano-chelate zinc foliar application on the expression of CYP71D180 and CYP71D178 genes was significant at the level of 1% and on the expression of DXR and CYP71D180 genes at the level of 5% probability. In this study, the level of 2.5 mg / l nano-zinc chelate increased the expression of DXR gene by 27.36% compared to the control treatment. Also, foliar application of two levels of 2.5 and 3.5 mg / l increased the expression of gamaterpinene synthase genes by 51.13% and 2.38%, expression of CYP71D180 gene by 36.31% and 42.28, and the expression of CYP71D178 gene by 61.70% and 36.34%, respectively.