Constitutive expression of a blueberry FLOWERING LOCUS T gene hastens petunia plant flowering

Modulating the expression of FLOWERING LOCUS T (FT) is a powerful approach to modify plant flowering time. In this study, a blueberry (Vaccinium corymbosum) FT (VcFT), which showed a high identity (90%) to the petunia FT gene, was used to produce early flowering petunia plants. The VcFT driven by a constitutive CaMV 35S promoter was transferred into petunia (Petunia × hybrid) plants using Agrobacterium tumefaciens-mediated transformation. Constitutive expression of VcFT (VcFT-CX) resulted in early flowering in both T0 and T1 transgenic plants. Compared to the controls of non-transgenic and transgenic plants that contain only the nptII selectable marker, VcFT-CX transgenic T1 plants flowered 10–14 days earlier. Although the VcFT-CX transgenic T1 plants were shorter than both controls at the start of bloom, all plants showed no significant difference in plant height at the time of seed maturity. The results demonstrated that constitutive expression of a FT-LIKE gene is highly effective in accelerating flowering for petunia plants.