Expression specificity of the globulin-1 promoter driven transgene (chitinase) in maize seed tissues.

摘要

To determine the expression specificity of transgenes driven by the seed-specific promoter of the Zea mays (maize) globulin-1 (Glb1) gene, the antifungal genes, chitinase 18 (ch18) and β-1,3-glucanase II (glu) under the control of the Glbl promoter, were bombarded into maize Type I embryogenic calli. Sixteen independent transformed lines were obtained. Transgene integration was confirmed by Southern analysis and expression detected in embryos by northern analysis. Western analyses and enzyme activity assays showed that the chl8 transgene was expressed in embryos, in the pericarp plus aleurone and in the endosperm beginning about 14 d after pollination. Increased β- 1,3-glucanase activity was not detected. Western analysis of other plant tissues detected no CHI8 protein in leaves, stems and roots of young seedlings of two different chl8 transgenic lines. However, some CHI8 protein could be detected in leaf and root tissues of older plants and in silk, cob and husk tissues. No CHI8 protein was found in stems, tassels or pollen or in any tissues of nontransgenic plants. These results show that the Glbl promoter can drive transgene expression in all tissues of developing maize seeds with timing similar to that found for globulin-1 protein expression. Expression can also sometimes be found in some other tissues.