Post-transcriptional regulation of the expression of the flowering time gene FT in different light conditions

The shift from a vegetative to a reproductive phase is orchestrated by a number of genes including CONSTANS (CO), FLOWERING LOCUS T (FT), and SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1).Many plants, both perennial and annuals, including A. thaliana, initiate this transition in response to changes in day length. The light signal is perceived in the leaves and transmitted to the apex where it induces flowering and the FT mRNA has been found to be part of this signal. In order to study the regulation of FT, a heat inducible system has been used in this work. In this report I confirm that the flower initiation caused by activation of a Hsp::FT Hsp::GUS transgene requires light. Heat shock induction of GUS and FT suggests that there is no difference in the induction kinetics or the relative induction levels between the two constructs in light and dark, suggesting that the light conditions are not affecting the transcriptional regulation. Instead, my data suggest that FT expression in different light conditions might be controlled by a post-transcriptional regulation possibly including both FT mRNA stability and the efficiency of translation or stability of the FT protein. This regulation might contribute to the reduced efficiency of FT-induced flowering in darkness