Effect of ticarcillin/potassium clavulanate on callus growth and shoot regeneration in Agrobacterium-mediated transformation of tomato (Lycopersicon esculentum Mill.).

Ticarcillin/potassium clavulanate is a very effective combination of antibiotics to eliminate Agrobacterium tumefaciens during tomato transformation. It shows no toxicity to tomato tissues at a concentration of 150 mg/l and significantly promotes callus formation and shoot regeneration. The transformation frequency was raised more than 40% in comparison to cefotaxime. Cefotaxime itself did not inhibit callus growth in culture medium, but it clearly decreased shoot differentiation. Together with kanamycin, cefotaxime shows a strong negative effect on callus growth, shoot regeneration and transformation efficiency. Unlike the widely used carbenicillin and cefotaxime, ticarcillin/potassium clavulanate is light stable and resistant to inactivation by β-lactamase. Furthermore, ticarcillin/potassium clavulanate is more economical than carbenicillin and cefotaxime. In conclusion, ticarcillin/potassium clavulanate is a very good alternative to eliminate Agrobacterium tumefaciens in plant transformation and has the potential to be widely used for plants which are sensitive to carbenicillin and cefotaxime.