Abstract
FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) proteins share highly conserved amino acid residues but they play opposite regulatory roles in promoting and repressing the flowering response, respectively. Previous substitution models and functional analysis have identified several key amino acid residues which are critical for the promotion of flowering. However, the precise relationship between naturally occurring FT/TFL1 homologs and the mechanism of their role in flowering is still unclear. In this study, FT/TFL1 homologs from eight Rosaceae species, namely, Spiraea cantoniensis, Pyracantha fortuneana, Photinia serrulata, Fragaria ananassa, Rosa hybrida, Prunus mume, Prunus persica and Prunus yedoensis, were isolated. Three of these homologs were further characterized by functional analyses involving site-directed mutagenesis. The results showed that these FT/TFL1 homologs might have diverse functions despite sharing a high similarity of sequences or crystal structures. Functional analyses were conducted for the key FT amino acids, Tyr-85 and Gln-140. It revealed that TFL1 homologs cannot promote flowering simply by substitution with key FT amino acid residues. Mutations of the IYN triplet motif within segment C of exon 4 can prevent the FT homolog from promoting the flowering. Furthermore, physical interaction of FT homologous or mutated proteins with the transcription factor FD, together with their lipid-binding properties analysis, showed that it was not sufficient to trigger flowering. Thus, our findings revealed that the divergence of flowering time modulating by FT/TFL1 homologs is independent to interaction and binding activities.
Highlights
Flowering is a key developmental phase of the higher plants
Our findings provide evidence that the diversity of flowering time modulating by FLOWERING LOCUS T (FT)/TERMINAL FLOWER1 (TFL1) homologs is independent to their interaction and binding activities
The plant phosphatidylethanolaminebinding protein (PEBP) family can be divided into three major clades, i.e., the FT-like, MFT-like, and TFL1-like clades
Summary
Flowering is a key developmental phase of the higher plants. The transition from the vegetative to reproductive growth phase is tightly regulated by a complex arrangement of multiple signaling networks. In Arabidopsis thaliana, multiple regulatory pathways involved in the flowering have been thoroughly researched It includes photoperiod, vernalization, hormone, Divergence of Flowering Time Modulating autonomous, and age-dependent pathways (Mutasa-Göttgens and Hedden, 2009; Turnbull, 2011; Wang R.H. et al, 2011; Johansson and Staiger, 2015; Wagner, 2016). In BvFT1 it was shown that the alteration of three amino acids in the external loop structure could reverse its repressor function into a floral promotion role (Pin et al, 2010). Site mutation analysis of selected FT/TFL1 homologs identified a specific amino acid residue (N-154 of RoFT), not previously reported, to be important to the maintenance of floral promoting. Our findings provide evidence that the diversity of flowering time modulating by FT/TFL1 homologs is independent to their interaction and binding activities
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
