Delay in flowering and increase in biomass of transgenic tobacco expressing the Arabidopsis floral repressor gene FLOWERING LOCUS C

FLOWERING LOCUS C (FLC), a gene from Arabidopsis thaliana (L.) Heynh. that acts as a flowering repressor, was expressed in tobacco (Nicotiana tabacum L. 'Samsun'). Five putative transgenic lines were selected and examined for the presence of FLC. Genomic DNA and total RNA were isolated from the leaves and used for polymerase chain reaction (PCR) and RNA blot analysis, respectively. Both DNA and RNA tests confirmed the integration and transcription of FLC in all five lines and their T1 progenies. Transgenic plants in one line showed an average of 36 d delay in flowering time compared to control plants, and the overall mean for all lines was 14 d. Transgenic plants also displayed increased leaf size and biomass yield and reduced height at flowering time. It is important to note that the delay in flowering might have been caused by a slower rate of leaf initiation (i.e. nodes/day) rather than by a change in the flowering mechanism itself.