Basic helix-loop-helix (bHLH) transcription factors are involved in mediating plant responses to environmental stresses. However, its role in the stress response in banana is largely unknown. In this manuscript, a comprehensive analysis was conducted to reveal the involvement of MabHLHs and their significance in banana cold stress responses. A total of 366 putative MabHLH transcription factors were identified. These MabHLHs were named according to their chromosomal locations and grouped into 12 subfamilies, with segmental duplication events significantly contributing to the expansion of this family. Transcriptomic analysis based on WGCNA identified 37 in co-expression networks under cold stress conditions. Among these MabHLHs, MabHLH355 in the magenta module, belonging to the IIIe subfamily, was downregulated under cold stress and significantly correlated with phenotypic indices, including HO, MDA and O content. Dual-luciferase transient expression analysis and electrophoretic mobility shift assays showed that MabHLH355 activated the expression of and . Notably, transient overexpression of in banana fruit improved cold tolerance. In conclusion, low temperatures repressed the expression of MabHLH355, which decreased the expression of and , thereby contributing to the occurrence of chilling injuries in banana.

中文翻译：

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低温下调 MabHLH355 及其相关靶基因，负责在冷胁迫下清除香蕉皮中的 ROS

碱性螺旋-环-螺旋（bHLH）转录因子参与介导植物对环境胁迫的反应。然而，它在香蕉应激反应中的作用很大程度上未知。在这篇手稿中，进行了全面的分析，以揭示 MabHLH 的参与及其在香蕉冷应激反应中的重要性。总共鉴定了 366 个假定的 MabHLH 转录因子。这些 MabHLH 根据其染色体位置进行命名，并分为 12 个亚家族，片段重复事件对该家族的扩张做出了显着贡献。基于 WGCNA 的转录组分析在冷应激条件下鉴定出 37 个共表达网络。在这些 MabHLH 中，洋红色模块中的 MabHLH355 属于 IIIe 亚家族，在冷胁迫下表达下调，并且与表型指标（包括 HO、MDA 和 O 含量）显着相关。双荧光素酶瞬时表达分析和电泳迁移率变动分析表明 MabHLH355 激活 和 的表达。值得注意的是，香蕉果实中短暂过度表达可提高耐冷性。综上所述，低温抑制了MabHLH355的表达，从而降低了和的表达，从而导致了香蕉冷害的发生。