Provided is a method for the expression of a TGF-.beta. in a plant. A
chimeric nucleic acid sequence comprising: (1) a first nucleic acid
sequence capable of regulating the transcription in a plant cell of (2) a
second nucleic acid sequence, encoding a TGF-.beta., and adapted for
expression in the plant cell; and (3) a third nucleic acid sequence
encoding a termination region functional in said plant cell is introduced
into a plant cell and the plant cell grown to produce TGF-.beta.. The
nucleic acid sequence may preferably be adapted for expression in a plant
chloroplast. It is preferred that the TGF-.beta. is TGF-.beta.3, whether
full length or in the form of an active fragment.