[en] FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1) are key regulators of floral transition and inflorescence architecture. Although these proteins belong to the same family (PEBPs) and display very similar 3-D structures, they play antagonistic roles: FT promotes floral transition while TFL1 acts as a floral repressor. In order to find new mechanisms that could explain these opposite functions, we used a quantitative proteomic approach to analyse the interactome of FT and TFL1. To this end, we carried out pull-down assays using tagged FT or TFL1 proteins as baits and extracts of shoot meristems as preys. These protein extracts were isolated from inflorescence meristems of Brassica oleracea and transitional meristems of Sinapis alba plants that had been synchronously induced to flower. The interactors obtained from these samples were identified by mass spectrometry. To infer the Arabidopsis thaliana orthologs, the proteomes of 14 Brassicaceae species including A. thaliana, B. oleracea, and S. alba, were used to construct orthogroups using the OrthoFinder software. About 34 000 orthogroups, encompassing 95.8% of all proteins, allowed the identification of the A. thaliana proteins present in the same orthogroups as the putative FT and TFL1 interactors identified in B. oleracea or S. alba. These candidates are being validated by yeast two-hybrid and reverse genetics approaches.
