Endosperm specific expression of a gliadin-actin hybrid promoter in transgenic rice (Oryza sativa L.)

The far upstream regulatory region of the gamma-gliadin gene was isolated f rom a wheat genomic library and its tissue specific effect on the expressio n of a reporter gene driven by a constitutive promoter was studied in trans genic rice (Oryza sativa L.). Since in earlier studies the wheat gliadin pr omoter containing -300 box has been previously shown to be active specifica lly in the endosperm of transgenic plants, therefore a hybrid promoter cons truct was created from gamma-gliadin gene promoter far upstream region span ning from -421 to -71 bp and rice actin1 promoter from -95 to +12 bp. Downs tream of the hybrid promoter a beta-glucuronidase reporter gene (gusA) was fused. This construct was introduced into rice embryo by particle bombardme nt. Transgenic rice plants carrying the hybrid promoter linked to gusA were regenerated from bombarded embryos and grown up to T-2 generation for furt her studies. RNA analysis and histochemical localization of GUS in transgen ic rice plants revealed that the expression of the gene was highly specific in the endosperm, although the inserted transgene could be detected in eve ry tissue (leaf, root and seed) investigated.