Fig. 3: HSP90 acts as a positive regulator of root ABCB-mediated polar auxin transport.
From: HSP90 differentially stabilizes plant ABCB-type auxin transporters on the plasma membrane
a Epidermal IAA influx profiles along solvent or indicated drug-treated (each 5 μM) Arabidopsis wild-type and hsp90 roots. Positive fluxes represent a net IAA influx; n = 3. Heat-map presentation of epidermal influx rates; dashed lines indicate 100-μm distances from the root tip. Raw data in Supplementary Fig. 5. b Root basipetal but not acropetal PAT is inhibited by Geldanamycin (5 μM) treatment of 5 μM seedlings. Significant differences (p < 0.05) of means ± SE (n = 6 independent experiments, each with 10 seedlings) were determined using Ordinary One-way ANOVA (Tukey’s multiple comparison test) and are indicated by different lowercase letters; benzoic acid (diffusion) control in Supplementary Fig. 5. c Root basipetal PAT is inhibited in Arabidopsis hsp90 loss-of-function and HSP90RNAi mutant lines. Significant differences (p < 0.05) of means ± SE (n = 3 independent experiments, each with 5 seedlings) were determined using Ordinary One-way ANOVA (Dunnett’s multiple comparisons test) and are indicated by different lowercase letters; benzoic acid (diffusion) control in Supplementary Fig. 5. d. Mesophyll protoplast IAA transport is not significantly affected in Arabidopsis hsp90 loss-of-function and HSP90RNAi mutant lines. Significant differences (p < 0.05) of means ± SE (n = 10–12 independent protoplast preparations) were determined using Ordinary One-way ANOVA (Tukey’s multiple comparison test) and are indicated by different lowercase letters; benzoic acid (diffusion) control in Supplementary Fig. 5. e, f Relative auxin responses are altered by pharmacological or genetical inhibition of HSP90 visualized (e) and quantified (f) using the degradation auxin reporter, DII-VENUS. Significant differences (p < 0.05) of means ± SE (n = 3 independent experiments with each 5 seedlings) were determined using Ordinary One-way ANOVA (Tukey’s multiple comparison test) and are indicated by different lowercase letters. g Root auxin (IAA) levels quantified by GC-MS are increased in hsp90.1, hsp90.3, and HSP90RNAi mutant roots but not in hsp90.2 and hsp90.4. Significant differences (p < 0.05) of means ± SE (n = 4 independent experiments, each with 10 roots) were determined using Ordinary One-way ANOVA (Dunnett’s multiple comparisons test) and are indicated by different lowercase letters; shoot data in Supplementary Fig. 5. h Epidermal root twisting (twist angle) is significantly increased in twd1, hsp90.1, hsp90.3, and HSP90RNAi mutant lines. Significant differences (p < 0.05) of means ± SE (n = 4 independent experiments, each with 10 roots) were determined using Ordinary One-way ANOVA (Dunnett’s multiple comparisons test) and are indicated by different lowercase letters. Data are presented as box-and-whisker plots, where median and 25th and 75th percentiles are represented by the box itself and the middle line, respectively; means are indicated by a “+”. Source data are provided as a Source data file.
