A 6' gentamicin acetyltransferase gene allows effective selection of tobacco transformants using kanamycin as a substrate.

6' gentamicin acetyltransferases detoxify aminoglycoside antibiotics containing a 6' amino group. We tested whether a 6' gentamicin acetyltransferase gene (6' gat) of Shigella sp. is suitable as selectable gene in plant transformation using kanamycin (Km) as a substrate. A comparative transformation experiment using Nicotiana tabacum SR1 protoplasts showed that 6' gat is as effective for selection of transformants as the commonly used neomycin phosphotransferase II (nptII). In stably transformed plants we detected moderate levels of the 6' gat mRNA. An enzymatic assay was developed with which the acetyltransferase activity of the protein is easily demonstrated.