Fig. 3.

PCH1 and PCHL inhibit phyB dark reversion. Dual-wavelength ratiospectrophotometer quantification of the relative abundance of phyB in the active state (Pfr/Ptot) (a, c) and total phyB (Ptot) (b, d) in planta. a, b PhyB dark reversion is accelerated in the absence of PCH1 and PCHL. Four-day-old etiolated seedlings expressing phyB-GFP in PCH1/PCHL wild type (WT; phyA-211 phyB-9 phyB-GFP) or the mutant background (pch1 pchl; phyA-211 pch1 pchl phyB-GFP) were exposed to red light (R, 10 μmol m⁻² s⁻¹) for 3 h followed by incubation in darkness (D) for indicated times. c, d PhyB dark reversion is reduced in PCH1ox and PCHLox seedlings. Four-day-old etiolated seedlings expressing c-Myc-mCherry-PCH1 (PCH1ox) or c-Myc-mCherry-PCHL (PCHLox) in the phyB-GFP background were pre-irradiated with red light (R, 20 μmol m⁻² s⁻¹) for either 20 min (black lines and symbols) or 3 h (grey lines and symbols) followed by incubation in darkness (D). a–d Data are means of ≥ 4 biological replicates; error bars indicate ±s.e.m.