Influence of auxins on somatic embryogenesis and alkaloid accumulation in Leucojum aestivum callus

International audienceIn vitro cultures of Leucojum aestivum are considered as an alternative for the production of galanthamine, which is used for the symptomatic treatment of Alzheimer's disease. We studied the effects of auxins 2,4-dichlorophenoxyacetic acid (2,4-D), 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro-o-anisic acid (dicamba) at concentrations of 25 and 50 A mu M on the induction of embryogenic callus and its capacity to induce somatic embryogenesis and alkaloid accumulation. The embryogenic response of the explants was from 30% for 25 A mu M of dicamba to 100% for picloram (for both 25 and 50 A mu M). 2,4-D (50 A mu M) stimulated greater callus proliferation and somatic embryo induction as compared to the other auxins. Polyethylene glycol (PEG) stimulated somatic embryo maturation. Callus grown on media containing 50 A mu M of auxins produced fewer phenolic compounds as compared with callus grown on media containing 25 A mu M of auxins. GC-MS analyses showed seven alkaloids in the in vivo bulbs and two to four in callus culture. Galanthamine was detected in callus cultivated with 2,4-D (25, 50 A mu M), picloram (25 A mu M), and dicamba (50 A mu M). Other alkaloids, trisphaeridine, tazettine, and 11-hydroxyvittatine were accumulated only in callus growing on medium with picloram (50 A mu M)