Browsing by Subject "pOpON"

Inflorescence meristem development in plants generally falls into two types: one is the indeterminate type when the main axis keep growing and new flowers are initiated on its flank; while the other is the determinate type when the main axis terminates as a flower and growth continues sympodially. The Asteraceae plant family harbors a unique type of inflorescence, called the flower head. It combines up to hundreds of individual florets into a single structure, but its infloresecence meristem has a determinate fate and can only produce a certain number of florets before getting consumed. The genetic regulation of such determinacy has been recently brought into attention in Gerbera hybrida, a model system used for studying inflorescence and flower development in Asteraceae. So far, several genetic regulators have been identified regulating the determinacy of inflorescence meristem in Gerbera. This thesis aims to characterize new Gerbera transgenic lines to study the function of the Gerbera homolog of TERMINAL FLOWER 1 (GhTFL1). In Arabidopsis and other species, TFL1 is known to counteract with the flower meristem identity genes and maintain the indeterminacy of the inflorescence meristem. Previous results by overexpressing GhTFL1 under constitutive 35S promoter in Gerbera convert the determinate fate of inflorescence meristem into indeterminate. To better study the GhTFL1 function, an inducible overexpression system pOpON2-pOp6/LhGR-N was introduced, and the transgenic lines have been made for GhTFL1. In this this thesis, in total of 19 candidate lines were screened with GUS staining assay and RT-PCR. Two promising lines (TR4 and TR7) with strongest responses in GUS staining and high expression of the target gene were identified. Further treatment of dexamethasone was conducted in these two lines to the growing rosette; however, no clear phenotypes was observed in these lines. The treatment results suggested that further optimization should be made, in particular, the timing of treatment shall be the determining factor for a successful treatment.