FACTORS INFLUENCING AGROBACTERIUM-TUMEFACIENS-MEDIATED TRANSFORMATIONOF ARTEMISIA-ANNUA L

Following our previously described Agrobacterium tumefaciens-mediated transformation procedure for Artemisia annua L., we have undertaken se veral additional experiments to establish the importance of some param eters such as explant type, age of explant source, A. tumefaciens stra in and type of binary vector. Several binary vectors were useful for t he production of transgenic callus on explants of different ages. In t ransformed calli, a good correlation between integration and expressio n of foreign DNA was observed: different assays showed expression of b eta-Glucuronidase, neomycin phosphotransferase II, superoxide dismutas e and bleomycin acetyl transferase. The regeneration of transgenic pla nts required more restricted conditions. Only with the pTJK136 Vector could transgenic plants be obtained from leaf and stem explants from 1 2- to 18-week-old plants. Go-cultivation for 48 h seemed favorable for the regeneration of transgenic plants. Stable integration and express ion of the transgenes was also shown in the progeny.