STABLY TRANSFORMED-CELL LINES FROM PROTOPLASTS OF MAIZE ENDOSPERM SUSPENSION-CULTURES

Protoplasts were isolated from Zea mays (L.) A69Y endosperm suspension cultures and transformed by polyethylene glycol mediated DNA uptake w ith chimaeric gene constructs containing beta-glucuronidase (GUS) or n eomycin phosphotransferase II (NPTII); GUS-expressing and Kanamycin-re sistant cultures were recovered. The transformed cells showed integrat ion of the introduced foreign genes into genomic DNA and maintained th eir ability to synthesize endosperm-specific reserve proteins (zeins). No deletion or rearrangement of zein genes were observed in transform ed cultures. Stable transformation of cultured maize endosperm cells m ay therefore represent a new methodological approach for the study of the transcriptional regulation of endosperm-expressed genes.