AtGIS, a C2H2 zinc-finger transcription factor from Arabidopsis regulates glandular trichome development through GA signaling in tobacco.

Glandular trichome is specialized multicellular structures that have capability to synthesize and secrete secondary metabolites and protect plants from biotic and abiotic stresses. Our previous results revealed that the C2H2 zinc-finger transcription factors (GIS) acts upstream of GL3/EGL3-GL1-TTG1transcriptional activator complex to regulate trichome initiation through GA signal in Arabidopsis. In the present study, we are reporting that ectopic expression of AtGIS could regulate glandular trichome development through GA signaling in tobacco. X-gluc staining of various organs from transgenic plants showed that AtGIS expressed mainly in the glandular trichomes. Statistical analysis demonstrated that over expression of GIS increased significantly glandular trichome production on the leaf, stem, branch, and sepal in tobacco. After PAC treatment, reduction of glandular trichome production in transgenic plants was more severe with compared to wild type plants. Furthermore, GA treatment could induce expression of AtGIS. More importantly, our results also demonstrated that overexpressed AtGIS significantly affect the main components of trichome exudates, such as significantly increase the content of nicotine, Cembratriene-4, 6-diol. Taken together, these results suggest that ectopic expression of AtGIS regulates glandular trichome development and may play a key role in compounds secretion in tobacco.