MaHDA6-MaNAC154 module regulates the transcription of cell wall modification genes during banana fruit ripening

Abstract

Fruit ripening and softening is a complex physiological process that is governed by the expression of a wide range of genes, and histone modification is a critical mechanism for precise gene expression. Although previous studies have indicated that NAC transcription factor (TF) and histone deacetylase individually play important roles in fruit ripening, the molecular connection between these two proteins within the regulatory system underlying banana fruit ripening is poorly understood. Here, we characterized a banana NAC MaNAC154 that was a negative regulator of banana fruit ripening. MaNAC154 was shown to localize in the nucleus, and it could target the promoters of MaEXP1/2, MaPL2, MaPG1/X3 and MaXTH5/23/28 to repress their transcription. Importantly, MaNAC154 was found to interact with a histone deacetylase MaHDA6, and their interaction significantly enhanced MaNAC154-mediated transcriptional repression capacity. Moreover, the acetylation levels of histones H3 and H4 of MaEXP1/2, MaPL2, MaPG1/X3 and MaXTH5/23/28 were elevated in the ripening stage. Overall, our data establish a coordinated mechanism underpinning histone deacetylation and TF-mediated gene repression for banana fruit ripening, providing a novel molecular basis for controlling mechanism of fruit ripening and softening.