Synergistic effect of coronatine and sorbitol on artemisinin production in cell suspension culture of Artemisia annua L. cv. Anamed

Abstract

Artemisinin is an efficient anti-malarial drug and it possesses biological activity against a wide range of cancers. The combined application of two different elicitors can be an efficient way to increase the production of secondary metabolite in plant cell cultures. The results of coronatine (Cor) pretreatment and three concentrations of sorbitol were assessed on the growth, biochemical traits, expression of artemisinin biosynthetic genes, and artemisinin production in Artemisia annua cell suspension culture (CSC). After pretreating CSC with 0.05 µM Cor [on the 14th day (three days before the stationary phase) for 48 h], liquid medium in the culture flasks was decanted and replaced with fresh medium (containing 30 g/L sucrose) plus or minus sorbitol at selected concentrations (0, 20, 30, and 40 g/L) on day 16th (one day before the stationary phase). The sorbitol treatment enhanced the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2) and resulted in oxidative stress. Cor-pretreatment increased the activity of antioxidant enzymes and consequently it reduced H2O2 content and oxidative stress which resulted in decreased MDA content and better growth. The application of Cor plus sorbitol resulted in a dramatic enhancement in the expression of artemisinin biosynthetic genes and artemisinin production at all concentrations. The expression levels of artemisinin biosynthetic genes (about 7.66, 8.67, 8.67, and 8.33-fold in ADS, CYP71AV1, ALDH1, and DBR2 genes, respectively at 4 h after sorbitol treatment) and artemisinin production (9.33 mg/L, 8-fold) peaked at 30 g/L sorbitol plus Cor and decreased at 40 g/L sorbitol, probably because of higher oxidative stress. The simultaneous application of Cor and sorbitol resulted in a dramatic enhancement in the expression of artemisinin biosynthetic genes and artemisinin production owing to a synergistic or potentiating result.