Highly efficient transfer and stable integration of foreign DNA into partially digested rice cells using a pulsed electrophoretic drive

A new method has been developed to introduce foreign DNA into rice cells. Gene delivery occurred when an electrophoretic drive with cycles of intervallic electric field was applied to a mixture containing partially digested small cell groups (SCGs) and plasmid DNAs. Gene transfer efficiency was evaluated by the detection of -glucuronidase (GUS) activity resulting from expression of a chimaeric plasmid DNA. The optimal combination of treatment conditions (3 V/cm, 30 s pulse and 30 min electrophoretic run) produced a frequency of up to 8.2% of blue cells in transformed microcalluses 40 days after culture of treated SCGs without selection for kanamycin resistance. Southern hybridization showed that the foreign gene had integrated into the chromosomal DNA. These results demonstrate that pulsed electrophoretic drive is applicable to the transfer of foreign genes into plant cells.