AchMYC2 mediates ABA-induced suberin deposition by activating AchABCG6 during wound healing in harvested kiwifruit

Abscisic acid (ABA) is known to promote suberization, but its role in coordinating transmembrane transport processes has not been fully elucidated. In this study, wounded kiwifruit was treated with 0.5 mM ABA to investigate the regulatory mechanism underlying ABA-mediated suberin transport during wound healing. The results showed that ABA treatment significantly upregulated the expression of the AchMYC2 , AchABCG6-1 , AchABCG6-2 and increased ABCG transporter protein accumulation. Transient overexpression of AchMYC2 in kiwifruit significantly upregulated the transcription of AchABCGs and increased their protein abundance, concomitant with a marked enhancement of suberin deposition at wound sites. Subcellular localization analyses further revealed that AchABCG6-1 and AchABCG6-2 are predominantly localized to the plasma membrane. Consistently, transient overexpression of either AchABCG6-1 or AchABCG6-2 significantly promoted suberin accumulation, indicating that these transporters play essential roles in the transmembrane transport of suberin precursors and thereby facilitate wound-induced suberization. DNA affinity purification sequencing (DAP-seq) identified “CACGTG” as the conserved binding motif of AchMYC2, while yeast one-hybrid (Y1H), Dual-luciferase reporter (Dual-luc), and molecular docking (MD) further confirmed the direct binding of AchMYC2 to G-box motifs in the promoters of AchABCGs and the potential interaction of ABCG transporters with suberin monomers. Collectively, these results demonstrate that ABA activates an AchMYC2–ABCG regulatory module to enhance transmembrane transport of suberin monomers, thereby promoting suberin deposition and accelerating wound healing in kiwifruit.