Ethylene and abscisic acid (ABA) play crucial roles in the ripening and softening of persimmon fruit, and they can promote each other to accelerate the softening process. However, the underlying molecular mechanisms remain to be further elucidated. In this study, a transcription factor NAM ATAF1/2, CUC26 (DkNAC26) induced by ethylene was identified. It could increase the content of ABA in persimmon fruit by promoting the expression of ABA synthesis-related gene DkNCED2 + 3′, thereby reducing fruit firmness. On the other hand, ABA could induce the expression of transcription factor DkNAC28, which binds to the promoter region of the ethylene biosynthesis gene DkACS1, leading to an earlier ethylene burst and consequently accelerating fruit softening. This study elucidates the functional roles of two transcriptional activators, DkNAC26 and DkNAC28, in regulating the biosynthesis of ethylene and ABA and reveals a molecular mechanism through which these two hormones interact to promote fruit softening, providing a new perspective for hormone crosstalk that drives rapid softening in persimmon.

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