Genetic transformation of Artemisia annua by Agrobacterium tumefaciens and artemisinin synthesis in transformed cultures

Transformed organ cultures of Artemisia annua were established following infection with two wild type nopaline strains of Agrobacterium tumefaciens. Parameters like explant type, strain type, age of the plant source for explants, affected the tumorigenesis frequency significantly. Crown galls were formed both on in vivo and in vitro plants: 2-3% of the in vitro galls regenerated spontaneously to produce shooty teratoma of altered phenotype. Artemisinin contents were measured in all transformed as well as non-transformed clones. While shooty teratomas synthesized 0.063 +/- 0.002 g/100 g DW artemisinin, non-transformed shoots were found to synthesize only 0.0179 +/- 0.002 g/100 g DW of the compound. (C) 1997 Elsevier Science Ireland Ltd.