MdSPL14–MdWRKY24 module directly represses MdARR6 expression. A) Y1H assay showing that MdSPL14 and MdWRKY24 can bind to the MdARR6 promoter in yeast cells, respectively. B) Schematic diagram of the constructed reporter and effector vectors. C, D) LUC assay indicating that MdSPL14 and MdWRKY24 inhibit MdARR6 promoter activity in N. benthamiana, respectively. Data are means ± Sd (n = 3). Values with different letters are significantly different according to 1-way ANOVA followed by Tukey's test (P < 0.05). E) EMSA assay confirming that MdSPL14 and MdWRKY24 bind to the MdCKX5 promoter in vitro, respectively. F)MdARR6 promoter sequence analysis reveals the presence of GTAC and W-box-binding elements. G) EMSA assay showing that the addition of MdSPL14 and MdWRKY24 enhances binding to the biotin-labeled oligonucleotides of MdARR6, respectively. H) LUC assay showing that the coexpression of MdSPL14 and MdWRKY24 enhances inhibition of the MdARR6 promoter in apple calli, respectively.