Hyoscyamine production in hairy roots of three Datura species exposed to high-salt medium

Abstract

Several species of the genus Datura have been cultivated for their hyoscyamine content. Hyoscyamine production in field-cultivated plants can often be limited by environmental conditions. The culture of hairy roots obtained by inoculation of Datura explants with the A4 strain of Agrobacterium rhizogenes offers promising prospects for the in vitro production of hyoscyamine. The objectives of this study were to select high-quality hairy root lines and then optimize hyoscyamine production by applying a salt stress. Potassium chloride (KCl) and calcium chloride (CaCl2) were added at various elicitation times, and both had significant effects on hyoscyamine biosynthesis. The optimal concentration of KCl was 2 g L−1, combined with a contact time of 10 h for the selected Datura tatula line (LDT) and 24 h for the selected Datura stramonium (LDS) and Datura innoxia (LDI) lines. For CaCl2, the optimum concentration was 2 g L−1 for LDS and LDT, with respective elicitation times of 10 and 24 h. For LDI, the best result was obtained with a CaCl2 concentration of 1 g L−1 and an elicitation time of 24 h. The highest hyoscyamine levels obtained for LDS, LDT, and LDI were, respectively, 2.32-, 1.99-, and 1.85-fold the control levels with KCl elicitation and 2.08-, 2.07-, and 1.85-fold the control levels with CaCl2 elicitation. The line resulting from D. tatula elicited with 2 g L−1 CaCl2 for 24 h produced the most hyoscyamine content (16.978 mg g−1 DW), followed by LDI and then LDS.