MaWRKY147-MaMADS68 transcriptional cascade module regulates low-temperature-affected banana fruit ripening

Fleshy fruit undergoes a complex ripening process accompanied with changes in aroma, color, flavor, and texture, which is regulated by hormonal, genetic, and environmental factors. However, the transcriptional cascade mechanism underlying fruit ripening regulation remains obscure. Here, we characterized a transcriptional repressor, MaMADS68, screened from transcriptomic data related to low-temperature-affected ripening. In vitro and in vivo assays revealed that MaMADS68 binds directly to the promoters of a subset of fruit ripeningrelated genes, including MaAAT1, MaEXP2, MaEXP15L, MaXTH23L, MaXTH25L, MaACS1, along with a MaWRKY49 that activates MaACS1 expression, to repress their transcription. Notably, yeast one-hybrid screening assay revealed that MaWRKY147, another ripening-induced transcriptional repressor, directly binds to and represses the promoter of MaMADS68, weakening MaMADS68 ' s repressive activity on ripening-related target genes owing to their expression and thus resulting in fruit ripening delay. Collectively, the results of this study illustrate the molecular basis of the transcriptional cascade MaWRKY147-MaMADS68 in modulating low-temperature-affected banana fruit ripening, advancing our understanding of the transcriptional regulatory mechanisms underlying fruit ripening.