Establishment and optimization of cell growth in suspension culture of Papaver bracteatum: a biotechnology approach for thebaine production

Iranian poppy (Papaver bracteatum) is an important medicinal plant that is the main source of the opium alkaloids codeine, morphine, and thebaine. To establish an efficient protocol for cell suspension culture and growth, the effects of different plant growth regulators (2,4-D, NAA, BAP, and kinetin) on callus induction and cell suspension culture of Iranian poppy were evaluated. The maximum percentage of callus induction (86.67%) and fresh weight of callus were obtained in MS medium supplemented with 1 or 2 mg/L 2,4-D, 0.1 or 0.2 mg/L kinetin and 15 mg/L ascorbic acid. The addition of 15 mg/L ascorbic acid to the medium was effective in reducing browning of explants and calli. In cell suspension cultures, MS medium supplemented with 1 mg/L NAA, 1 mg/L BAP, and 15 mg/L ascorbic acid gave maximum cell growth and proliferation compared to other treatments evaluated. Among the auxins, NAA was more effective than 2,4-D for growth of P. bracteatum cell suspension cultures. However, there was no statistically significant difference between kinetin and BAP. The thebaine yield of P. bracteatum cell suspension at 12 days after culture was 4.67 μg/g dry weight, which was significantly lower than that at 16 days (10.76 μg/g dry weight).