A SIMPLE PROCEDURE FOR THE EXPRESSION OF GENES IN TRANSGENIC SOYBEAN CALLUS-TISSUE

Cotyledons from germinating seeds of the soybean cultivar Peking were inoculated with virulent Agrobacterium tumefaciens strain A281:pZA-7 w hich carries a wild type Ti plasmid pTiBo542 and a disarmed Ti plasmid (a binary vector)pZA-7 which contains the beta-glucuronidase (uidA) a nd neomycin phosphotransferase (nptII) genes. Tumors were produced on all inoculated explants and 82% of these tumor lines were cotransforme d by the nptII gene from the binary vector pZA-7 as shown by PCR analy sis (18 of 22 lines tested). Eleven of these 18 lines were also resist ant to kanamycin. Eleven lines expressed beta-glucuronidase activity ( GUS), six of which were also kanamycin resistant. Since there is a hig h rate of coexpression of genes carried by the binary vector, this sys tem provides a simple and rapid method for the expression of genes of interest in transformed soybean tissue which has been used successfull y to test constructs designed for soybean transformation.