Fig. 6

MdNAC1 binds the MdEXP-A1 promoter and promotes its transcriptional activity. A Location analysis of NAC-binding cis-acting elements in the MdEXP-A1 promoter sequence. B Yeast one-hybrid assay results showing showed that MdNAC1 can interact with the P-2 fragment of the MdEXP-A1 promoter, and the empty vector (AD) was used as a negative control. C The probe in the MdEXP-A1 promoter sequence, the binding probe, is a biotin-labeled fragment containing an [ACG] motif. The cold probe is an unlabeled competitive probe (50 times the concentration of the binding probe). The mutation probe contains seven or six nucleotide substitutions. D Electrophoretic mobility shift assays revealed that MdNAC1 binds to the specific motifs P1 and P2 of the MdEXP-A1 promoter. The ‘ + ’ and ‘-’ represent the presence and absence of the probe or protein, respectively. E Constructs used to test the role of MdNAC1 in MdEXP-A1 expression in transient expression assays. F and G LUC assay indicating that MdNAC1 positively promotes the activity of the MdEXP-A1 promoter. The values are the means ± SDs of three independent biological replicates; Asterisks indicate significant differences determined via a t test (**P < 0.01)