Fig. 4: FT competes TFL1 from the chromatin.
From: TERMINAL FLOWER 1-FD complex target genes and competition with FLOWERING LOCUS T
a LFY locus and primers used. b Top: FT-HAER occupancy at the LFY locus after 4-h mock (M) or steroid (T) treatment. Bottom: gTFL1 occupancy in the same sample. c, d Effect of FT upregulation by photoperiod (FRP, 24 h) on TFL1 (c) or FD (d) occupancy at the LFY locus. e FT-HAER recruitment to LFY exon 2 (e2) or a bZIP-binding site mutated version thereof (e2m3) after 4-hour steroid treatment. Top: LFY exon 2 (e2, black rectangle) and T-DNA vector (grey line). Centre: location of amplicons P1 and P2, each consisting of one exon 2-specific and one vector-specific primer. Below: FT-HAER ChIP-qPCR. Progeny pools of >50 random FT-HAER T1 plants transformed with e2 or e2m3 were analyzed (see also ref. 108). f Effect of photoperiod (FRP) on TFL1 occupancy at TFL1–FD target loci identified in Fig. 1f and LMI267 g FT-HAER occupancy with or without 4-h estradiol treatment at TFL1–FD bound regions of target loci shown in f. b–g ChIP was performed in 42-day-old short-day-grown plants. Shown are mean ± SEM of three independent biological experiments (black dots). P values (unpaired one-tailed t-test): b anti-HA ChIP ** region 4 = 0.009, region 5 = 0.003; anti-GFP ChIP ***region 4 = 6E−05, region 5 = 0.006; c *region 4 = 0.039, **; region 5 = 0.002; d n.s. LFY = 0.18, TA3 = 0.29. e **P1 = 0.004, P2 = 0.002, n.s. TA3 = 0.12; f * GI = 0.016, ***CO = 0.0007, **SOC1 = 0.0015, ***FUL = 0.0003, ***AP1 = 0.007, LMI2 = 0.0011, n.s. TA3 = 0.34. g **GI = 0.009, *CO = 0.011, **SOC1 = 0.003, *FUL = 0.015, ***AP1 = 0.0001, **LMI2 = 0.008, n.s TA3 = 0.17. h Model for antagonistic roles of TFL1 (purple circles) and FT (red circles) in promoting branch fate or floral fate, respectively. Increased FT accumulation leads to competition of TFL1 from bZIP transcription factor FD bound to chromatin and to onset of flower formation. FD dimers (orange ovals), 14-3-3 proteins (black disks).
