Stable transformation of maize after gene transfer by electroporation

The graminaceous monocots, including the economically important cereals, seem to be refractory to infection by Agrobacterium tumefaciens¹, a natural gene transfer system that has been successfully exploited for transferring foreign genes into higher plants^2-4. Therefore, direct transfer techniques that are potentially applicable to all plant species have been developed using a few dicot^5-8 and monocot^8-10 species as model systems. One of these techniques, electroporation, uses electrical pulses of high field strength to permeabilize cell membranes ¹¹ reversibly so as to facilitate the transfer of DNA into cells ^8,12,13. Electroporation-mediated gene transfer has resulted in stably transformed animal cells^12,13 and transient gene expression in monocot and dicot plant cells⁸. Here we report that electroporation-mediated DNA transfer of a chimaeric gene encoding neomycin phosphotransferase results in stably transformed maize cells that are resistant to kanamycin.