The banana (Musa spp.) peel undergoes rapid softening during ripening, leading to finger drop and a shortened shelf life. The regulatory mechanism behind this process remains to be elucidated. In this study, we confirmed the role of peel softening in banana finger drop and uncovered the underlying transcriptional regulatory network. Cell wall-related (CWR) genes were substantially upregulated in both the peel and finger drop zone during ethylene-induced ripening. Transcriptome analysis and genome-wide profiling of chromatin accessibility and transcription factor (TF) binding revealed that two key regulators of fruit ripening, Musa acuminata NAC-like, Activated by apetala3/Pistillata1 (MaNAP1) and MaMADS1, regulate CWR genes by directly binding to their promoters or by targeting other ripening-related TFs to form a hierarchical regulatory network. Notably, MaNAP1 and MaMADS1 were directly targeted by ETHYLENE INSENSITIVE3 (MaEIN3), and MaNAP1 and MaMADS1 associated with tissue-specific histone modifications, enabling them to integrate MaEIN3-mediated ethylene signaling and undergo epigenetic regulation. Overexpression of MaNAP1, MaMADS1 or other identified regulatory TFs upregulated CWR genes and promoted peel softening. Our findings unveil a MaNAP1-MaMADS1-centered regulatory cascade governing banana peel softening and finger drop, offering potential targets for enhancing banana texture and shelf life.

Bananas (Musa spp.) are among the most important fruit and staple food crops globally, holding a significant strategic position in food security in tropical and subtropical regions. However, the industry is grappling with a significant threat from Fusarium wilt, a disease incited by Fusarium oxysporum f. sp. cubense (Foc). In this study, we explored the potential of Piriformospora indica (Pi), a mycorrhizal fungus renowned for bolstering plant resilience and nutrient assimilation, to fortify bananas against this devastating disease. Through a meticulous comparative analysis of mRNA and miRNA expression in control, Foc-inoculated, Pi-colonized, and Pi-colonized followed by Foc-inoculated plants via transcriptome and sRNAome, we uncovered a significant enrichment of differentially expressed genes (DEGs) and DE miRNAs in pathways associated with plant growth and development, glutathione metabolism, and stress response. Our findings suggest that P. indica plays a pivotal role in bolstering banana resistance to Foc. We propose that P. indica modulates the expression of key genes, such as glutathione S-transferase (GST), and transcription factors (TFs), including TCP, through miRNAs, thus augmenting the plant’s defensive capabilities. This study offers novel perspectives on harnessing P. indica for the management of banana wilt disease.

Banana (Musa spp.) fruit peel browning during cold storage results in significant postharvest losses; however, the molecular mechanisms linking antioxidant metabolism and transcriptional regulation remain unclear. Here, we demonstrate that exogenous ascorbic acid alleviates chilling-induced browning by suppressing the WRKY-AAO regulatory module through histone H3K18 lactylation (H3K18la)-mediated chromatin remodeling. DNase-seq analyses revealed that cold stress induces chromatin accessibility at the promoters of WRKY transcription factor genes (MaWRKY11/18/40/50/60). DNA affinity purification sequencing (DAP-seq) and yeast one-hybrid confirmed these WRKYs can bind to W-box motifs in the ascorbate oxidase (MaAAO1) promoter. This activation triggered ascorbic acid depletion and reactive oxygen species accumulation, accelerating peel browning. Conversely, ascorbic acid treatment reduced H3K18la levels at MaWRKY genes, diminishing their accessibility and lowering the expression of MaWRKY target genes. Transient overexpression assays confirmed that MaAAO1 drives peel browning, while ascorbic acid disrupts this cascade by coupling redox signaling to lactylation-dependent chromatin silencing. Our study unveils a redox-sensitive epigenetic switch wherein exogenous ascorbic acid mitigates chilling injury by repressing oxidative pathways via histone lactylation, offering strategies for preserving tropical fruit quality.