Figure 5.

POR overexpression rescues the loss of HEMA1 expression in WL following growth in FRc or NF. A, Effect of a combined FR preirradiation and NF treatment on the WL response of a HEMA1 promoter:gusA reporter gene. WT seedlings were grown with or without 3% (w/v) Suc for 3 d in FRc or darkness prior to transfer to WL (130 μmol m⁻² s⁻¹) for an additional 3 d. NF was included in the media at 5 μm and resulted in the cotyledons appearing completely white under all treatments. Values were normalized to the respective dark control levels (=100) within each experiment. Data shown are the mean ± se (n = 5). B, HEMA1 promoter:gusA expression in phyA seedlings under the same conditions as shown in A. C, The effect of POR overexpression on HEMA1 expression. Seedlings of PORA- or PORB-overexpressors (PAO-3 and PBO-1) were germinated in the dark without Suc and were irradiated for 0 to 3 d under FRc. HEMA1 mRNA accumulation was measured following transfer to WL (130 μmol m⁻² s⁻¹). D, The effect of 5 μm NF on the accumulation of HEMA1 mRNA in WL-irradiated seedlings of WT and transgenic lines overexpressing PORA (PAO-3) or PORB (PBO-1). Seedlings were grown in the absence of Suc for 3 d in the dark prior to transfer to WL for an additional 3 d.