Fig. 6

MdNAC4 activates the expression of MdSAG39. a Diagram of the MdSAG39 gene promoter region. P1 and P2 represent the potential sites to which MdNAC4 might bind. b The electrophoretic mobility shift assay (EMSA) showed that the MdNAC4-GST fusion protein bound to the MdSAG39 promoter. 5x, 50x and 100x represent the competitor concentrations. Unlabeled probes were used as competitors, with “Mut” representing the mutated probe in which the 5′-ACGTG-3′ motif was replaced by 5′-CCGTC − 3′. c A yeast one-hybrid (Y1H) assay revealed the interaction between MdNAC4 and the MdSAG39 promoter. The cotransformed yeast strains were grown on SD/−L-U and SD/−L-U + 100 mM AbA medium for 3 days. d Dual luciferase assays of tobacco leaves showed that MdNAC4 activated the expression of MdSAG39. e Relative LUC/REN activity analysis verified that MdNAC4 activated the expression of MdNCED2. Tobacco injected with the empty vector was used as the control. Error bars indicate the SDs of the three technical replicates and three biological replicates. Different letters above the bars indicate significant differences according to one-way ANOVA (P < 0.05)