Low temperature-induced regulatory network rewiring via WRKY regulators during banana peel browning

Abstract

Banana (Musa spp.) fruits, as typical tropical fruits, are cold sensitive, and lower temperatures can disrupt cellular compartmentalization and lead to severe browning. How tropical fruits respond to low temperature compared to the cold response mechanisms of model plants remains unknown. Here, we systematically characterized the changes in chromatin accessibility, histone modifications, distal cis-regulatory elements, transcription factor binding, and gene expression levels in banana peels in response to low temperature. Dynamic patterns of cold-induced transcripts were generally accompanied by concordant chromatin accessibility and histone modification changes. These upregulated genes were enriched for WRKY binding sites in their promoters and/or active enhancers. Compared to banana peel at room temperature, large amounts of banana WRKYs were specifically induced by cold and mediated enhancer-promoter interactions regulating critical browning pathways, including phospholipid degradation, oxidation, and cold tolerance. This hypothesis was supported by DNA affinity purification sequencing, luciferase reporter assays and transient expression assay. Together, our findings highlight widespread transcriptional reprogramming via WRKYs during banana peel browning at low temperature and provide an extensive resource for studying gene regulation in tropical plants in response to cold stress, as well as potential targets for improving cold tolerance and shelf-life of tropical fruits.

The Role of MaWRKY70 in Regulating Lipoxygenase Gene Transcription during Chilling Injury Development in Banana Fruit

“…WRKY TFs could activate or inhibit the transcription of target genes by specifically recognizing the W-box binding elements in the downstream target gene promoter region, and they then participate in plant development and the stress response [ 42 ]. For example, FvWRKY50 promoted the expression of FvCHI and FvDFR by binding to their promoters in strawberry fruit [ 22 ].…”

Dissecting postharvest chilling injuries in pome and stone fruit through integrated omics

“…Other than CI detection, machine-learning approaches should be used to unravel the molecular mechanisms involved in CI development and alleviation. ChromHMM an unsupervised machine learning algorithm used to identify chromatin states, to annotate their occurrence across the genome, and facilitate their biological interpretation ( Ernst and Kellis, 2017 ) has been used for CI research in bananas ( Zhu et al., 2023 ). This study provided a multi-omics integrative approach to chromatin accessibility, histone modifications, distal cis-regulatory elements localization, transcription factor binding, and gene expression in cold-induced banana peel browning.…”