Abstract

Introduction The banana industry faces challenges in maintaining sweetness during postharvest handling, as conventional ethylene ripening often compromises starch-to-sugar conversion. Current technologies lack modulation of this metabolic pathway. Emerging epigenetic tools offer promise for sugar enhancement. Objectives This study investigates how the DNA demethylating agent 5-azacytidine (AZ) epigenetically reprograms the starch-to-sugar conversion in banana pulp under ethylene. The further goal is to advance the understanding of fruit epigenetic regulation, inspiring a molecular-level strategy to optimize postharvest fruit traits. Methods Bananas underwent optimized vacuum infiltration with 1 mmol/L AZ or control solution (−0.08 MPa, 30 min), followed by ethylene-induced ripening. Assays included biochemical measurements (Spectrophotometry), key gene expression (qRT-PCR), promoter-specific DNA methylation (McrBC-PCR), and translational regulation (polysome profiling). At least 3 biological replicates were used and significance ( p  < 0.05) was analyzed by two‑way ANOVA or t‑tests with Bonferroni/FDR correction. Results Only combined with ethylene fumigation, AZ significantly elevated total soluble solids and soluble sugars (sucrose, glucose, fructose) with up to a 2.1-fold increase over the control (ethylene only), correlating with accelerated starch degradation. The activation of 70.27% (26/37) starch-degrading genes and increased enzyme activity (α-amylase, β-amylase, debranching enzymes) were observed. On one hand, AZ induced global DNA demethylation and promoter hypomethylation for key starch-degrading genes (e.g., MaGWD1 , MaBAM11 , MaAMY3 ). This DNA hypomethylation-dependent mechanism strongly correlated with gene activation ( p ＜0.001). On the other hand, polysome profiling demonstrated that AZ directly enhanced the total translation efficiency and specific translation efficiency of key starch-degrading transcripts such as MaBAM3 , MaBAM11 , and MaI