Role of TRS120 phosphorylation status on adaptive growth responses under additive stress conditions. (A) TRS120-WT (PTRS120::TRS120:GFP in trs120-4/trs120-4) (Rybak et al., 2014). (B) The non-phosphorylatable TRS120-SαβγA in trs120-4/trs120-4. (C) The phosphomimetic TRS120-SαβγD in trs120-4/trs120-4. TRS120-SαβγD mutants had attenuated root and ratio responses under darkW, whereas TRS120-SαβγA mutants showed a slightly enhanced root response. (D) Total seedling lengths of TRS120-WT, TRS120-SαβγA, and TRS120-SαβγD. The hypocotyl length is depicted in green and the root in beige-brown shades with an increasing opacity gradient for the different conditions. The total seedling length did not vary from the TRS120-WT control, highlighting the adaptation defect of TRS120-SαβγD to darkW. Seedlings were grown on ½ MS media under light, dark and dark with −0.4 MPa water stress (darkW) conditions. For each line, four biological replicates were analyzed. Values are means ± SD of measured seedlings per condition, number (n) of seedlings are given in gray below the graphs. A representative line, based on the RQ and P values, is depicted for A–C. For total seedling lengths, means ± SD of four biological replicates are shown. Stars indicate statistical significance with a two-tailed Student’s t test (*: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001; *****: P < 0.00001). Related to Fig. 7.
