Interaction of MaERF11 with the E3 ubiquitin ligase MaRFA1 is involved in the regulation of banana starch degradation during postharvest ripening

Abstract

Banana fruit ripening is a highly regulatory process involving various layers consisting of transcriptional regulation, epigenetic factor, and post-translational modification. Previously, we reported that MaERF11 cooperated with MaHDA1 to precisely regulate the transcription of ripening-associated genes via histone deacetylation. However, whether MaERF11 is subjected to post-translational modification during banana ripening is largely unknown. In this study, we found that MaERF11 targeted a subset of starch degradation-related genes using the DNA affinity purification sequence (DAP-Seq) approach. Electrophoresis mobility shift assay (EMSA) and dual-luciferase reporter assay (DLR) demonstrated that MaERF11 could specifically bind and repress the expression of the starch degradation-related genes MaAMY3, MaBAM2 and MaGWD1. Further analyses of yeast two-hybrid (Y2H), bimolecular fluorescence complementation (BiFC) and Luciferase complementation imaging (LCI) assays indicated that MaERF11 interacted with the ubiquitin E3 ligase MaRFA1, and this interaction weakened the MaERF11-mediated transcriptional repression capacity. Collectively, our results suggest an additional regulatory layer in which MaERF11 regulates banana fruit ripening and expands the regulatory network in fruit ripening at the post-translational modification level.