摘要
β-galactosidases (EC 3.2.1.23) constitute a widespread family of glycosyl hydrolases in plants and are thought to be involved in metabolism of cell wall polysaccharides. A cDNA of the cotton (Gossypium hirsutum) β-galactosidase gene, designated GhGal1, has previously been identified and its transcripts are highly abundant at the elongation stage of the cotton fiber. To examine the temporal and spatial control of GhGal1 expression, a transcriptional fusion of the GhGal1 promoter region (1770 bp) with the β-glucuronidase (GUS) reporter gene was introduced into tobacco plants by the Agrobacterium infection method. The resulting transgenic plants showed higher GUS activity of fruit in the transgenic plants than that in the negative and positive controls. Histochemical localization of GUS activity demonstrated that the expression of the GUS gene could be found in the meristem zones of roots, cotyledons, vascular tissues, fruit and trichomes in transgenic tobacco plants. Additionally, se-quence analysis of the regulatory region also revealed several conserved motifs among which some were shared with previously reported fruit/seed-specific elements and the others were related with trichome expression. These results indicated the temporal and spatial expression characterization of the GhGal1 promoter in transgenic tobacco plants and provided an important insight into the roles of GhGal1 in cotton fiber development.
β-galactosidases (EC 3.2.1.23) constitute a widespread family of glycosylhydrolases in plants and are thought to be involved in metabolism of cell wall polysaccharides. AcDNA of the cotton (Gossypium hirsutum) β-galactosidase gene, designated GhGal1, has previouslybeen identified and its transcripts are highly abundant at the elongation stage of the cotton fiber.To examine the temporal and spatial control of GhGal1 expression, a transcriptional fusion of theGhGal1 promoter region (1770 bp) with the β-glucuronidase (GUS) reporter gene was introduced intotobacco plants by the Agrobacterium infection method. The resulting transgenic plants showed higherGUS activity of fruit in the transgenic plants than that in the negative and positive controls.Histochemical localization of GUS activity demonstrated that the expression of the GUS gene could befound in the meristem zones of roots, cotyledons, vascular tissues, fruit and trichomes intransgenic tobacco plants. Additionally, sequence analysis of the regulatory region also revealedseveral conserved motifs among which some were shared with previously reported fruit/seed-specificelements and the others were related with trichome expression. These results indicated the temporaland spatial expression characterization of the GhGal1 promoter in transgenic tobacco plants andprovided an important insight into the roles of GhGal1 in cotton fiber development.
