Submitted to: Acta Horticulture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2010
Publication Date: 7/1/2014
Citation: Yang, Y., Zhong, G. 2014. Characterization of grape GA1 promoter in Arabidopsis. Acta Horticulturae Proceedings (ISHS). 1046:379-384.
Technical Abstract: GAI (GA insensitive) gene plays a central role in plant GA (Gibberellin) signaling. Mutations in a GAI gene can result in changes of plant architecture and other traits, thus providing potential opportunities for crop improvement. As a step of exploring GAI variants for the improvement of grapevine (Vitis vinifera L.), we cloned a 2-kb promoter region of the grape GAI gene (VvGAI) and characterized its activities in Arabidopsis thaliana along with that of a 2-kb Arabidopsis GAI promoter (AtGAI) and 35S cauliflower mosaic virus promoter (35S). All the three promoters were fused to the GUS reporter gene (beta -glucuronidase) (designated as pVv::GUS, pAt::GUS or p35S::GUS). GUS expression activities of the three constructs were visually examined at both seedling and reproductive stages in transgenic Arabidopsis plants. Our results demonstrated that both VvGAI and AtGAI promoters showed strong activities in the actively growing tissues such as young shoots and new leaves, root tips, lateral root primordia and young inflorescences. The GAI promoter activities were significantly reduced in older leaves, roots and stems. This suggests that there is a very tight developmental control of GAI expression in plants. Some subtle differences were observed between VvGAI and AtGAI promoters in the reporter expression activities in the stamen filaments of flowers. The pVv::GUS construct had much stronger expression in stamen filaments than pAt::GUS. This observation was interesting as it might suggest that the regulatory control system for the same gene could vary in different species. A major difference of expression activities between 35S and GAI promoters was found in roots. At seedling stages, strong reporter expression was observed for 35S::GUS in all root tissues including primary, lateral and tertiary roots, but there was almost no reporter expression in the primary roots of either pVv::GUS or pAt::GUS plants.