Direct gene transfer to plant protoplasts by electroporation by alternating, rectangular and exponentially decaying pulses.

The efficiency of electroporation of sugar beet (Beta vulgaris L.) and tobacco (Nicotiana tabacum L.) protoplasts by alternating, rectangular and exponentially decaying pulses was studied by assaying transient expression of an introduced gene for chloramphenicol acetyltransferase. A simple device for electroporation by alternating current was constructed. The mains (220 V) were used as power supply and the pulse duration was controlled by the blow-out of a small fuse. Electroporation of sugar beet protoplasts by alternating current and exponentially decaying pulses resulted in 3-4 fold higher transient expression compared to rectangular pulses. Transient expression in tobacco protoplasts electroporated by exponentially decaying pulses was 30 % and 85 % higher than when electroporated by rectangular and alternating current pulses, respectively.