Fig. 5. Auxin response is higher in shaded conditions than in warm temperature and is predominantly regulated by PIF7 in shade at 21 or 30 °C.

a Expression of SAUR22, SAUR19, YUC9, and YUC8 in 3-d-old seedlings grown in constant white light (70 µmol m⁻² s⁻¹) at 21 °C plus the indicated time in the stated conditions. Relative expression assayed using RT-qPCR relative to the reference gene IPP2. The average values of three biological replicates per condition +/− SE shown. b Relative expression of all SAUR genes that show differential expression in at least one condition assayed by RNA-seq (Log₂FC < −1 or >1, FDR < 0.05). Expression in 3-day-old seedlings (grown in constant simulated white light- 70 µmol m⁻² s⁻¹ at 21 °C) plus the indicated time in each of the conditions, shown as Log₂FC relative to 21WL. Different letters denote statistical differences (p < 0.05) between conditions, within each time point as determined by one-way ANOVA and Tukey HSD test. Boxes indicate the first and third quartiles and the whiskers indicate the minimum and maximum values, the black lines within the boxes indicate the median values and gray dots mark the individual measurements n = 18 genes. c Images of GUS-stained whole Arabidopsis seedlings carrying a SAUR19p:GUS reporter. Plants were grown in constant simulated white light (70 µmol m⁻² s⁻¹) at 21 °C plus 6 h or 8 h in the conditions indicated on the left. d Expression of YUC8 and SAUR22 in 3-d-old wild-type, pif45, pif7, and pif457 seedlings grown in constant simulated white light (70 µmol m⁻² s⁻¹) at 21 °C plus 4 h in the stated condition. Gene expression was assayed using RT-qPCR relative to the reference gene IPP2 and normalized to the expression in wild type at 21WL. The average values of three biological replicates per condition +/− SE are shown. Different letters denote statistical differences (p < 0.05) among samples as assessed by one-way ANOVA and Tukey HSD test.