THE USE OF AMOXICILLIN AND TICARCILLIN IN COMBINATION WITH A BETA-LACTAMASE INHIBITOR AS DECONTAMINATING AGENTS IN THE AGROBACTERIUM-TUMEFACIENS-MEDIATED TRANSFORMATION OF ARTEMISIA-ANNUA L

Artemisinin is a new very promising antimalarial compound produced in the areal parts of the plant Artemisia annua L. (Asteraceae). There is a great interest in the overproduction of artemisinin by means of tra nsgenic plants. The existing Agrobacterium tumefaciens-mediated transf ormation procedure uses the expensive decontaminating agent vancomycin . In addition vancomycin exhibits a low activity against the Agrobacte ria. This paper describes the use of the penicillin derivatives amoxic illin and ticarcillin in combination with the beta-lactamase inhibitor clavulanic acid, on the market as Augmentin(R) and Timentin(R) (Smith Kline Beecham Pharma S.A., Genval, Belgium), respectively. Sensitivit y studies revealed that those antibiotics still permit plant regenerat ion. The leaf disc transformation was performed with the C58C1 (pGV226 0; pTJK136) Agrobacterium strain. Transgenic tissue was selected on 20 mg l(-1) kanamycin. The integration of the foreign genes was proven b y polymerase chain reactions and additional DNA sequencing, beta-Glucu ronidase gene expression analyses were performed. In all cases transge nic callus could be obtained, but the shoot regeneration failed. Decon tamination was most efficient when high initial concentrations of Augm entin(R) and Timentin(R) (300 and 200 mg l(-1), respectively) were use d. Those concentrations can gradually be reduced. We may conclude that decontamination by the penicillin derived antibiotics is cheaper and more efficient than vancomycin, but is only suitable when the producti on of callus is desired, for example for the establishment of cell cul tures. (C) 1996 Elsevier Science B.V. All rights reserved.