The Effect of Nano Cobalt and Nano Chitosan on Artemisinin production and expression of SQS and DBR2 genes in Artemisia annua

Artemisia annua is particularly important for the production of artemisinin, a bioproduct which can be used to combat the causal agent of malaria, treat some kind of cancers and in other activities. The low artemisinin content in the plant has caused this compound to be among the more expensive medicines. Several attempts have been made to increase artemisinin production, for example by using different elicitors, but none of the approaches has been cost effective. In this study, the expression levels of two important genes in the artemisinin biosynthetic pathway, SQS and DBR2 and artemisinin content were investigated in Artemisia cell suspension cultures. SQS and DBR2 genes have essential roles in the regulation of artemisinin pathway. For this purpose, nano-cobalt particles in concentrations of 0.25, 2.5 and 5 mg/L were used for cell culture treatment and samples were collected after 8, 24, 48 and 72 h. The highest artemisinin content was observed 24 h after 5 mg/L nanocobalt treatment. In this case, artemisinin production was 2.25 times (113.35 mg/g d.wt) higher than that of the control. Our results showed a negative and significant correlation between SQS and DBR2 gene expression and artemisinin content at different levels of nano cobalt treatments. Results also showed an increase in nano cobalt concentration after 72 hour and an increase in nano chitosan after 4h hour caused a significant decrease in the expression of SQS and DBR2 genes. In conclusion, it appears that the content of artemisinin was increased by high concentrations of the nano cobalt particles because of a decrease in the expression of SQS and DBR2 genes.