Abstract
In a day neutral plant tomato, three FT homologues (SP3D, SP5G and SP6A) have been cloned. Since the late-flowering mutant, sft, has a mutation in the SP3D gene, it is considered to be an FT orthologue in tomato. However, the functions of SP5G and SP6A in tomato remain unclear. To investigate the relationship between day-length and expression of FT homologues in tomato, we examined diurnal gene expression under various day-length conditions. While the SP3D gene does not respond to day-length, SP5G expression is very low under short-day conditions and shows a peak at ZT-4h. under long-day conditions. SP6A expression is too low to detect. We are now investigating the function of SP5G in the flowering pathway using overexpression and knockdown transgenic plants. We are also examining the expression patterns of these genes of short-day plants among wild tomato species.
