Aleurone- and embryo-specific expression of the β-glucuronidase gene controlled by the barley Chi26 and Ltp1 promoters in transgenic rice

Abstract.

Two barley aleurone-specific promoters from genes encoding lipid transfer protein (Ltp1) and chitinase (Chi26), respectively, were transcriptionally fused to a β-glucuronidase gene (GUS). Tissue-specific expression of these GUS chimeric constructs was examined in transgenic rice. Histochemical analysis of individual transformants revealed that GUS expression could be detected only in the grains of transgenic rice containing each chimeric construct. GUS expression under the control of the Chi26 promoter was specifically observed in the aleurone layers of rice grains. In contrast, GUS gene coupled to the Ltp1 promoter was not expressed in the aleurone layers but expressed only in embryo tissue. This distinct expression pattern of two barley aleurone-specific promoters in transgenic rice grains implies that the molecular mechanism underlying the aleurone-specific expression from those promoters may be different.