Tissue-specific and ABA-regulated Maize GIN gene expression in transgenic tobacco.

To study the regulatory functions of the ON promoter region, a ppG1b1GUS construct, consisting of 1402 bp 5' flanking sequence ofGlbl, 1919 by GUS coding sequence, and 283 by 3' NOS terminator, was cloned into a binary vector and introduced into tobacco plants byAgrobacterium-mediated transformation. Histochemical GUS assays of To tobacco mature seeds indicate that theGlbl promoter drives GUS expression in ABA treated seeds. Further GUS assays of the T, seeds at different developmental stages revealed that without ABA treatment, theGibl promoter drives GUS expression in immature seeds. The results from both To and T1 tobacco plants indicated thatGlbl-driven GUS expression in tobacco is embryo specific.