Factors influencing Agrobacterium tumefaciens-mediated transformation of Artemisia annua l.

Following our previously described Agrobacterium tumefaciens-mediated transformation procedure for Artemisia annua L., we have undertaken several additional experiments to establish the importance of some parameters such as explant type, age of explant source, A. tumefaciens strain and type of binary vector. Several binary vectors were useful for the production of transgenic callus on explants of different ages. In transformed calli, a good correlation between integration and expression of foreign DNA was observed: different assays showed expression of beta-Glucuronidase, neomycin phosphotransferase II, superoxide dismutase and bleomycin acetyl transferase. The regeneration of transgenic plants required more restricted conditions. Only with the pTJK136 Vector could transgenic plants be obtained from leaf and stem explants from 12- to 18-week-old plants. Go-cultivation for 48 h seemed favorable for the regeneration of transgenic plants. Stable integration and expression of the transgenes was also shown in the progeny.