Enhanced secondary metabolites’ production in rol A transformed Artemisia absinthium L. and Chloroplast genome based phylogenic studies of Artemisia Genus

Abstract

For centuries, plants in the genus Artemisia L. have been used for medicinal purposes. These aromatic plants produce and store a number of secondary metabolites that have antioxidant, anti-inflammatory, antimicrobial, and anti-cancer properties. For extensive studies of the therapeutic potential and economical industrial production of these compounds, improved biosynthesis is required. Plant transformation with Agrobacterium rhizgenes rol genes has been an effective approach for increasing plant secondary metabolite biosynthesis. Present study was primarily focused on the transformation of Artemisia absinthium with rol A gene mediated by Agrobacterium tumefacien. The aim of this transformation was to enhance the secondary metabolites production in A. absinthium. Transgenic A. absinthium lines were analyzed for stable integration of the rol A transgene into the plant genome, and spatiotemporal expression of flavonoid biosynthetic genes, terpenoid biosynthesis genes, artemisinin pathway genes, transcription factors genes, trichome synthesis genes and transporters genes. Further, total phenolic contents (TPC), total flavonoid contents (TFC), antioxidant activities of extracts were also analyzed. Various in-vitro, cell lines-based assays were performed for comparison of transformed and untransformed A. absinthium. Expression of all metabolic pathway related genes were significantly increased in all transformed lines with highest in RolA2 transgenic plants as compared to wild type untransformed. Generally, total phenolic content up to 2.88-fold and total flavonoid content up to 34.62-folds was increased in transgenic plants. Total antioxidant capacity (TAC) and total reducing power (TRP) was increased up to 188% while, DPPH, lipid peroxidation and anti-leishmania assay had shown significant inhibition with low IC 50 value <100 μg/ml, in rol A transgenic plants. Similar effects were also observed in the in-vitro antidiabetic and Alzheimer’s assay, which showed maximum inhibition of enzymes with IC 50 value up to 200 μg/ml, while untransformed plant had IC 50 value up to 560 + 5.29 μg/ml. The current findings pave way for future research to identify biologically active compounds in the extract of A. absinthium and the potential of these bioactive compounds in different physiological disorders.