Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt.
A pair of related genes with antagonistic roles in mediating flowering signals.
-
FT promotes flowering and is positively regulated by CONSTANS (CO) in the long-day photoperiodic pathway; loss of FT delays flowering and overexpression causes precocious, CO/photoperiod-independent flowering.
"FT, together with LFY, promotes flowering and is positively regulated by CO. Loss of FT causes delay in flowering, whereas overexpression of FT results in precocious flowering independent of CO or photoperiod."
-
FT acts in part downstream of CO and mediates flowering signals antagonistically with its paralog TERMINAL FLOWER1 (TFL1), establishing the FT/TFL1 antagonism that tunes the floral transition.
"FT acts in part downstream of CO and mediates signals for flowering in an antagonistic manner with its homologous gene, TERMINAL FLOWER1 (TFL1)."
Activation tagging of the floral inducer FT.
-
FT was isolated by activation tagging as a floral inducer acting in parallel with the meristem-identity gene LEAFY (LFY), partially downstream of CONSTANS (CO).
"FLOWERING LOCUS T (FT), which acts in parallel with the meristem-identity gene LEAFY (LFY) to induce flowering of Arabidopsis, was isolated by activation tagging. Like LFY, FT acts partially downstream of CONSTANS (CO), which promotes flowering in response to long days."
-
The deduced FT protein sequence is similar to TERMINAL FLOWER1 (an inhibitor of flowering) and to membrane-associated mammalian PEBP-family proteins; FT does not directly control transcription or transcript processing, foreshadowing its role as a non-DNA-binding signaling protein.
"Unlike many other floral regulators, the deduced sequence of the FT protein does not suggest that it directly controls transcription or transcript processing. Instead, it is similar to the sequence of TERMINAL FLOWER 1 (TFL1), an inhibitor of flowering that also shares sequence similarity with membrane-associated mammalian proteins."
FD, a bZIP protein mediating signals from the floral pathway integrator FT at the shoot apex.
-
FT and the bZIP transcription factor FD are interdependent partners (via protein interaction) that act together at the shoot apex to promote floral transition, providing the molecular basis for FT's transcription-coactivator role.
"FD and FT are interdependent partners through protein interaction and act at the shoot apex to promote floral transition and to initiate floral development through transcriptional activation of a floral meristem identity gene, APETALA1 (AP1)."
-
The FT/FD complex transcriptionally activates APETALA1 (AP1), a floral meristem-identity gene, providing direct support for FT involvement in positive regulation of flower development.
"FD and FT are interdependent partners through protein interaction and act at the shoot apex to promote floral transition and to initiate floral development through transcriptional activation of a floral meristem identity gene, APETALA1 (AP1)."
-
FT mRNA is expressed in the vasculature of cotyledons and leaves, while FD is preferentially expressed in the shoot apex, consistent with FT being a leaf-derived long-distance signal that meets its bZIP partner at the apex.
"FLOWERING LOCUS T (FT) is a conserved promoter of flowering that acts downstream of various regulatory pathways, including one that mediates photoperiodic induction through CONSTANS (CO), and is expressed in the vasculature of cotyledons and leaves. A bZIP transcription factor, FD, preferentially expressed in the shoot apex is required for FT to promote flowering."
Integration of spatial and temporal information during floral induction in Arabidopsis.
-
A primary response to floral induction is activation of FT RNA expression in leaves; because flowers form at the distant shoot apex, FT (a small, possibly mobile protein) integrates temporal information for flowering.
"A primary response to floral induction is the activation of FT RNA expression in leaves. Because flowers form at a distant site, the shoot apex, these data suggest that FT primarily controls the timing of flowering."
-
A complex of FT and FD proteins activates floral identity genes such as APETALA1 (AP1), confirming the FT-FD activation module mediates floral meristem identity transcription.
"A complex of FT and FD proteins in turn can activate floral identity genes such as APETALA1 (AP1)."
Molecular basis of late-flowering phenotype caused by dominant epi-alleles of the FWA locus in Arabidopsis.
-
Ectopic FWA blocks the flowering pathway at or downstream of FT, with FWA binding to FT (yeast two-hybrid and pull-down) suggesting FWA delays flowering by interfering with FT/FD complex formation.
"The previous reports that fwa suppressed the precocious-flowering phenotype of plants overexpressing FLOWERING LOCUS T (FT) suggest that the flowering pathway(s) either at and/or downstream of FT is blocked by FWA."
FT protein movement contributes to long-distance signaling in floral induction of Arabidopsis.
-
FT mRNA is required only transiently in the leaf; FT fusion proteins expressed specifically in phloem cells move to the apex and across grafts, providing direct evidence that FT protein acts as a long-distance (florigenic) signal.
"We found that FT messenger RNA is required only transiently in the leaf. In addition, FT fusion proteins expressed specifically in phloem cells move to the apex and move long distances between grafted plants."
-
FT does not activate an intermediate messenger in leaves; therefore FT protein itself constitutes the long-distance signal that induces Arabidopsis flowering.
"we provide evidence that FT does not activate an intermediate messenger in leaves. We conclude that FT protein acts as a long-distance signal that induces Arabidopsis flowering."
Genetic and spatial interactions between FT, TSF and SVP during the early stages of floral induction in Arabidopsis.
-
FT and its paralog TSF redundantly mediate photoperiodic flowering; the ft tsf double mutant is photoperiod-insensitive and fully suppresses the early-flowering phenotype of CO overexpression.
"we show that FT and the closely related TSF are not essential for flowering, but that the double mutant is photoperiod-insensitive. Inactivation of both genes also fully suppresses the early-flowering phenotype caused by over-expression of constans (CO), a transcriptional regulator in the photoperiod pathway."
-
FT and TSF interact with the same bZIP transcription factors (FD/FDP-class) in yeast, demonstrating shared biochemical function as transcription-coactivator partners of bZIPs.
"we demonstrate that TSF and FT have similar biochemical functions by showing that they interact in yeast with the same bZIP transcription factors."
-
Phloem-companion-cell-specific FT or TSF expression rescues flowering in ft tsf double mutants, demonstrating that FT need not be expressed in the meristem and is loaded into the phloem from companion cells.
"Expression of FT or TSF from promoters specific for phloem companion cells drives early flowering of the double mutant, so no expression of either gene is required in the meristem."
-
FT and TSF are repressed by the MADS-box transcription factor SVP, integrating SVP repression into the FT/TSF photoperiodic flowering pathway.
"TSF, like FT, is repressed by SVP"
Arabidopsis BLADE-ON-PETIOLE1 and 2 promote floral meristem fate and determinacy in a previously undefined pathway targeting APETALA1 and AGAMOUS-LIKE24.
-
BOP1/2 promote floral meristem identity by upregulating APETALA1 via direct interactions with TGA bZIP transcription factors at the AP1 promoter, defining a parallel pathway to FT/FD that converges on AP1.
"BOP1/2 are recruited to the promoter of AP1 through direct interactions with TGA bZIP transcription factors"
-
BOP1/2, LFY and AP1 converge to down-regulate flowering-time regulators including AGAMOUS-LIKE24 in stage 2 floral meristems, providing context for how the FT/FD-AP1 pathway is fine-tuned by parallel inputs.
"all three activities converge to down-regulate flowering-time regulators including AGAMOUS-LIKE24 in stage 2 floral meristems"
FLOWERING LOCUS T regulates stomatal opening.
-
FT is expressed in guard cells and regulates stomatal opening downstream of phototropin (phot1/phot2) blue-light signaling, indicating an additional, non-floral role for FT in guard cells.
"FLOWERING LOCUS T (FT) is expressed in guard cells and regulates stomatal opening."
-
The scs1-1 (elf3 phot1 phot2) suppressor shows open stomata with high H+-ATPase activity, linking FT/ELF3 to guard-cell H+-ATPase activation; supports an annotation of FT to stomatal-opening regulation as a non-core/clock-output role.
"scs1-1 (elf3 phot1 phot2 triple mutant) had an open-stomata phenotype with high H(+)-ATPase activity"
FTIP1 is an essential regulator required for florigen transport.
-
FT-INTERACTING PROTEIN 1 (FTIP1), an ER membrane protein, is essential for FT protein transport to the shoot apex in Arabidopsis; loss of FTIP1 causes late flowering under long days partly via compromised FT movement, establishing that florigen transport is a regulated process.
"FT-INTERACTING PROTEIN 1 (FTIP1), is an essential regulator required for FT protein transport in Arabidopsis. Loss of function of FTIP1 exhibits late flowering under long days, which is partly due to the compromised FT movement to the shoot apex."
-
FTIP1 and FT share similar mRNA expression patterns and subcellular localization and interact directly, indicating an active loading/trafficking mechanism for FT in phloem companion cells.
"FTIP1 and FT share similar mRNA expression patterns and subcellular localization, and they interact"
Characterization of Multiple C2 Domain and Transmembrane Region Proteins in Arabidopsis.
-
Systematic characterization of the 16-member Arabidopsis MCTP family confirms that MCTP1 (FTIP1) C2 domains cooperate to regulate FTIP1's role in FT-dependent flowering-time control, supporting the regulated trafficking of FT.
"We further analyze in vivo effects of three C2 domains on the regulatory role of MCTP1 (FTIP1) in flowering time control in Arabidopsis, demonstrating that these C2 domains may be cooperative to mediate FTIP1 function during the floral transition."
Genetic interactions reveal the antagonistic roles of FT/TSF and TFL1 in the determination of inflorescence meristem identity in Arabidopsis.
-
FT/TSF and TFL1 act antagonistically in inflorescence meristem identity: ft tsf mutants generate a hyper-vegetative shoot (like TFL1 overexpression) while FT or TSF overexpression generates a terminal flower (like tfl1 mutants), placing FT in inflorescence-meristem identity control.
"The ft-10 tsf-1 mutants produced a compact inflorescence surrounded by serrated leaves (hyper-vegetative shoot) at the early bolting stage, as did plants overexpressing TFL1. Plants overexpressing FT or TSF (or both FT and TFL1) generated a terminal flower, as did tfl1-20 mutants."
-
Grafting demonstrates that long-distance FT signal from a 35S::FT rootstock restores normal inflorescence patterning to ft tsf scions, confirming FT functions as a mobile florigen in inflorescence meristem identity.
"Grafting ft-10 tsf-1 or ft-10 tsf-1 tfl1-20 mutant scions to 35S::FT rootstock plants produced a normal inflorescence and a terminal flower in the scion plants, respectively"
Deep research on FT function
-
Synthesis of the FT literature - FT is a leaf-produced mobile floral stimulus (florigen) that, after long-distance transport through the phloem, partners with FD-class bZIP transcription factors at the shoot apex to activate floral meristem-identity genes (AP1, SOC1, LFY).
Falcon (Edison Scientific) deep research on Arabidopsis FT (florigen) function, transport, and mode of action at the shoot apical meristem
-
"In *Arabidopsis*, **FT encodes a mobile protein signal** produced in
leaves that is transported to the SAM, where it triggers the
vegetative-to-reproductive phase transition."
-
"FT is **not an enzyme** and does not catalyze a chemical reaction.
Instead, it functions as a **mobile signaling
protein/transcriptional co-regulator** that promotes flowering by
forming protein complexes at the SAM with DNA-binding transcription
factors."
-
"Reviews emphasize that PEBP-family proteins such as FT do **not bind
DNA directly**, but act through interaction with transcriptional
regulators such as bZIP factors in the FD class."
-
"FT expression is activated in leaf **phloem companion cells (CCs)**
under inductive conditions (notably long days), and the **FT protein
is loaded into sieve elements (SEs)** for phloem transport."
-
"Once in the SEs, FT traffics through the **phloem stream** to the
shoot. This movement is considered regulated, not a simple diffusion
process."
-
"At the **shoot apical meristem**, FT participates in complexes that
reprogram gene expression toward floral fate, including activation of
floral meristem identity programs."
-
"The antagonistic PEBP-family member **TFL1** is described as opposing
FT function at shared FD-bound targets, effectively tuning floral
induction by competition at the SAM."
-
"CO directly activates **FT** transcription in leaves; FT is the key
floral pathway integrator under long days"