Effects of cobalt nanoparticles on artemisinin production and gene expression in Artemisia annua

The low artemisinin content in Artemisia has caused this compound to be expensive among medicines. Several attempts have been made to increase its production by altering the expression of different genes. However, no approach has been cost-effective. In this study, the expression levels of SQS and DBR2 genes were quantified by qRT-PCR, and artemisinin content was measured by HPLC in Artemisia annua cell suspension culture under nano cobalt particles elicitation. For this purpose, nano cobalt particles were used in 0.25, 2.5, and 5 mg L-1 concentrations and samples were collected after 8, 24, 48, and 72 h. The highest artemisinin content was observed 24 h after 5 mg L-1 nano cobalt treatment. In this case, artemisinin production was 2.25-fold (113.35 mg g-1 dw) higher than that of the control. Simultaneously, the expression levels of SQS and DBR2 genes decreased. It appears that the decrease in the expression of SQS and DBR2 genes caused the artemisinin content to increase by high concentrations of the nano cobalt particles.