High-efficiency transformation of Agrobacterium tumefaciens with plasmid DNA by electroporation

We describe a very simple and highly efficient procedure for direct transformation of Agrobacterium tumefaciens with plasmid DNA. The protocol is based on high-voltage electropermeabilization of whole cells, and reproducible yields of 107 to 5 x 108 transformants per µg of plasmid DNA are obtained. basically electroporation is performed in 15% polyethylene glycol using an electrical field strength of 12.5 kV/cm. The utility of this transformation method is demonstrated by direct establishment in Agrobacterium tumefaciens of a representative genomic library from the plant Arabidopsis thaliana. Our results offer interesting prospects for the transfer of gene banks and for gene complementation in plants without the use of Escherichia coli as an intermediate host.