Arsenic, chromium and NaCl induced artemisinin biosynthesis in Artemisia annua L.: A valuable antimalarial plant

• Arsenic, chromium and NaCl induced changes in plant growth, herb yield and artemisinin biosynthesis.
• Artemisia annua plants can grows well in favoring with artemisinin biosynthesis at low doses of As(III) and NaCl.
• Artemisinin biosynthesis and plant growth were affected in Cr(VI) treated sand.
• Silimarly Plant growth was also affected with all the doses of heavy metals and NaCl.

Effect of As(III), Cr(VI) and NaCl on plant growth, antioxidant enzymes, SOD, TBRAS, protein, cDNA amplification of key genes of artemisinin pathway and artemisinin biosynthesis have been investigated to explore the actual changes in total herb and artemisinin yield in a crop cycle of Artemisia annua. Enhanced TBARS and SOD activity (4 U mg−1), decreased catalase activity and total cholorophyll content were observed under metal(loid) and NaCl stress. Accumulation of As (III; µg mg−1 DW) was higher in roots (10.75±0.00) than shoot (0.43±0.00) at 10 µg ml−1. While Cr(VI; µg ml−1 DW) accumulated more in shoots (37±9.6, 41.1±7.2 and 52.71±19.6). cDNA template of these treated plants along with control were amplified with HMGR, ADS and CYP71AV1 genes (artemisinin biosynthetic pathway genes); showed very low expression with Cr(VI) while As(III) (5 and 7.5 µg ml−1) showed higher expression than control. The results obtained from this study suggest that A. annua can grow well with favoring artemisinin biosynthesis with treatment of As(III) 5, 7.5 µg ml−1 and NaCl, while 10 µg ml−1 As(III) and all doses of Cr(VI) affect artemisinin synthesis. Finally some evidence also suggests that As(III), Cr(VI) and NaCl induces stress affects on total herb yield of plant.