MdMYB88 and MdMYB124 regulate MdMYB46 and MdVND6 expression by directly targeting their promoters. A and B, Expression level of MdVND6 and MdMYB46 in roots of GL-3, MdMYB88 or MdMYB124 overexpression plants, and MdMYB88/124 RNAi plants in response to drought stress. Plants were subjected to 20% PEG8000 for 0 or 6 h. Data are means ± sd (n = 3). C and D, Yeast one-hybrid analysis of interaction between MdMYB88 and MdVND6 (C) and MdMYB46 (D) promoters. AbA concentration is 500 ng/mL. E and F, ChIP-qPCR analysis of MdVND6 (E) and MdMYB46 (F) binding by MdMYB88 and MdMYB124. MDH is the negative control, also serves as the reference gene. Fragments MdVND6-a and MdMYB46-a serve as negative controls in E and F, respectively. Fragments MdVND6-b and MdMYB46-b both contain cis-element of AACCG. Data are means ± sd (n = 3). G and H, EMSA analysis of MdMYB88-His binding to the promoter region of MdVND6 (G) and MdMYB46 (H). Arrowheads indicate protein-DNA complex or free probe.