Genetically Transformed Root-Based Culture Technology in Medicinal Plant Cosmos bipinnatus

Background: Cosmos bipinnatus is an important medicinal plant with antioxidative, antigenotoxic, anti-inflammatory, and anti-proliferative effects on several cancer cell lines. It has great potential for development as a promising cancer chemo-preventive agent. Hairy root-based culture technology is a new sustainable production platform for producing specific pharmaceutical secondary metabolites. Objectives: The current study developed and introduced a reliable transformation system for C. bipinnatus by optimization of aspects important in transformation frequency using Agrobacterium rhizogenes. Methods: Five bacterial strains, including ATCC 15834, ATCC 31798, A7, MAFF-02-10266, and MSU440, 2 explant types (leaf and stem), and 2 co-cultivation media (full MS and 1/2 MS) were examined. Genomic DNA was extracted using a modified CTAB protocol from putative transgenic root lines and the control root. Transgenic hairy root lines were approved by means of Polymerase Chain Reaction (PCR) using specific rolB gene primers. Results: The highest ratio of genetically transformed root induction was found from leaf explants using A. rhisogenes strains ATCC15834 and MSU440 (72% to 73%). When 1/2 MS medium was used as a co-cultivation medium, a significant increase in transformation frequency (84%) was observed. Conclusions: The MSU440 Agrobacterium strain and 1/2 MS co-cultivation medium could significantly improve genetic transformation efficiency for establishment of hairy root-based cultures for C. bipinnatus.