Fig. 3

HD2B plays a role in plant immunity and shuttles from the nucleolus to the nucleoplasm. a Susceptibility of hd2b mutant and independent hd2b transgenic lines expressing an unphosphorylatable version of HD2B-AA (hd2b pHD2B::GFP-HD2B-AA #1 and #2) to Pseudomonas syringae pv. tomato hrcC- was compared to that of WT Col-0 and to a complemented mutant line (hd2b pHD2B::GFP-HD2B) as a control. Fourteen-day-old in vitro seedlings were incubated with a suspension of Pst hrcC-, and bacteria were quantified 2 h (day 0) and two days (day 2) after inoculation. hd2b mutant plants and GFP-HD2B-AA lines showed enhanced susceptibility compared with col-0 and with the non-mutated GFP-HD2B complemented line. Average values and standard deviations were calculated from three independent experiments. For each condition (day 0, day 2), a one-way ANOVA followed by an all pairwise multiple comparison procedure was performed (Holm-Sidak method, 23 > n > 8, p < 0.05). b Immunofluorescence staining was performed on pHD2B::GFP-HD2B rosette leaves either mock-treated or elicited with flg22 for 30 min. In mock-treated tissues, GFP-HD2B was localized to the nucleolus while GFP-HD2B was observed in the whole nucleus after flg22 treatment. Scale bars, 5 μm. c GFP-HD2B-ED that mimics a constitutively phosphorylated version of HD2B was stably expressed in Arabidopsis plants and accumulated in the nucleoplasm while GFP-HD2B-AA was localized in the nucleolus. Scale bars, 5 μm