Abstract
We reported at the former meeting that Arabidopsis FT (AtFT) under rolC promoter set flowers in vitro in 3 to 5 months after the transformation. In this experiment, Arabidopsis TWIN SISTER OF FT (TSF) was introduced to apple under 35S or rolC promoter. The 35S::AtFT transformed apple showed early flowering in vitro, but the flowers on the shoot tips were 5 mm long and died without blossom. The 35S::TSF and rolC::TSF transformed apple set flowers in vitro, respectively. The precocious effect by FT gene was supposed the following order, AtFT >TSF>MdFT. The 35S promoter was more effective than rolC. These results meant that the precociousness was highly affected by the FT gene species and promoters. In the case of AtFT fused GFP, 35S::AtFT/GFP or rolC::AtFT/GFP transformed apple could be detected with the fluorescence from GFP and the fused proteins. But both transformants did not set flowers in vitro at all. These results suggested that the promotion of apple flowering by each FT gene depended on their protein sequences and structures. Then we tried to compare with the sequence between MdFT1, MdFT2, AtFT, TSF and Hd3a and analyzed the domains for the precocious effects.
