Comparison of gene order in the chromosome region containing a TERMINAL FLOWER 1 homolog in apricot and peach reveals microsynteny across angiosperms

The TERMINAL FLOWER 1 (TFL1) plays crucial roles in regulating the vegetative to reproductive phase transition and maintaining the inflorescence meristem. We characterized one apricot (Pa_GBa141J23) and one peach (Pp_NBa103A15) BAC clone harboring a TFL1 gene. Sequence analysis revealed that the apricot and peach TFL1 (PaTFL1 and PpTFL1) genes display a similar exon–intron organization to homologs from other eudicot species and the defined amino acid domains are preserved. Phylogenetic analysis grouped PaTFL1 and PpTFL1 with the Arabidopsis ortholog. Numerous cis-elements present in the upstream regulatory region of the Arabidopsis TFl1 were identified in the PaTFL1 and PpTFL1 promoter regions. Two TFL1 alleles involving SSR polymorphism exist in the ‘Nemared’ peach cultivar. All nine genes annotated in the apricot Pa_GBa141J23 BAC have the same gene order in the peach genome. Syntenic regions are present in angiosperm species around the TFL1 locus, with the size of syntenic region decreasing from eudicots to monocots.