Fig. 1.

The photoreceptor phyB is SUMOylated in seedlings grown in RL/D cycles. (A) Analysis of A. thaliana (At, NP_179469), Solanum lycopersicum (Sl, XP_010318997), Oryza sativa (Os, EEE58928), Triticum aestivum (Ta, BAP91202), and Zea mays (Zm, NP_001168077) phyB protein sequences by SUMOsp 2.0 software identified sequence motifs as potential targets for SUMOylation. The Lys996 amino acid of the conserved SUMOylation site for AtphyB is indicated by an arrow. Numbers at the beginning and at the end of the presented sequences indicate the corresponding amino acid positions, and numbers in brackets show the length of PHYB proteins from different species. (B) phyB-9 seedlings expressing the 35S:PHYB-GFP transgene were grown on MS medium in 12 h RL (25 µmol m⁻²·s⁻¹)/12 h D cycles and 12 h FRL (10 µmol m⁻²·s⁻¹)/12 h D cycles for 5 d. Samples were harvested on day 6, at MOD and MON. phyB-GFP was immunoprecipitated by using GFP-Trap agarose beads (IP:αGFP), and samples containing identical amounts of the fusion protein were analyzed. phyB-GFP was detected by anti-GFP (IB:αGFP), whereas AtSUMO1-conjugated phyB-GFP was visualized using anti-SUMO1 antibody (IB:αSUMO1).