Figure 4.

Phosphorylation of Ser-86 Affects Photobody Dissociation but Not the Abundance of phyB.

(A) phyB^Ser86Ala-YFP photobodies exhibit increased stability under FR light irradiation. Transgenic phyB-9 seedlings expressing the phyB-GFP (S86S), phyB^Ser86Ala-YFP (S86A), and phyB^Ser86Asp-YFP (S86D) fusion proteins were grown for 5 d in darkness and then exposed to 24 h of R light (22 µmol m⁻² s⁻¹) followed by irradiation with FR light for 5 min (20 µmol m⁻² s⁻¹). phyB-associated photobodies were monitored as described by Pfeiffer et al. (2012). The experiments were repeated three times (n = 50), and representative pictures are shown. Bars = 10 µm.

(B) Substitutions of Ser-86 do not alter cR-induced degradation of the various phyB fusion proteins. Transgenic phyB-9 seedlings were grown in darkness for 4 d on wet filter paper and exposed to cR (0.1 µmol m⁻² s⁻¹) as indicated. The levels of the various fusion proteins were determined by immunoblot analysis using anti-GFP antibody. The lanes contain equal amounts of total protein as shown by the comparable levels of actin.