Influence of salicylic acid, methyl jasmonate, and yeast elicitors on a shikonin level in hairy root culture of Echium khuzestanicm

Purpose Elicitors are powerful agents for enhancing the production of secondary metabolites in plants by stimulating specific cellular pathways. This study investigates Echium khuzestanicum , a native Iranian herb, with the innovative approach of utilizing a temporary immersion bioreactor in combination with biotic and abiotic elicitors to optimize growth rates and maximize shikonin production. Methods We conducted a series of treatments in a temporary immersion culture to increase the shikonin content in hairy roots. The treatments included salicylic acid, methyl jasmonate, yeast, and combinations of these compounds. Various treatment protocols were implemented using the immersion bioreactor system, which involved different cycles for immersion and drought periods. Results Our results indicate that the most effective treatment was a drying period of 45 minutes followed by 15 minutes of immersion. Notably, methyl jasmonate at a concentration of 150 µM produced the highest growth rate and shikonin yield. The combination of 150 µM methyl jasmonate with 500 µM salicylic acid further enhanced secondary metabolite synthesis. While yeast at 1000 mg/L increased shikonin content, it did not significantly influence growth rates. Conclusion These findings highlight the innovative use of temporary immersion bioreactors alongside targeted elicitors as a promising strategy to enhance secondary metabolite production in Echium khuzestanicum , thereby contributing valuable insights for future research in plant biotechnology.