Epigenetic regulation for delaying tomato fruit ripening through histone modification by specific sound wave treatment

Controlling fruit ripening is crucial for maintaining its quality during delivery. A specific sound wave treatment to delay fruit ripening without genetic modifications has been identified as an effective method in tomatoes. However, the molecular mechanisms of the sound wave-triggered suppression of fruit ripening remain largely unknown. In this study, we demonstrated that sound waves influence histone modifications, particularly at ethylene biosynthesis-related genetic loci, inhibiting transcription. Sound waves reduced histone modifications involved in transcriptional activation but increased repressive histone modifications at the RIN, NOR, and TAGL1 genes, which are positive regulators of fruit ripening. Similar epigenetic events have also been observed in genes encoding ethylene biosynthesis enzymes. Sound wave treatment upregulated the expression of histone modifi-cation enzyme genes involved in H3 methylation and deacetylation but downregulated those involved in H3 demethylation and acetylation. In addition, histone-modifying enzymes may directly associate with promoters of RIN, NOR, and TAGL1 genes and indirectly associate with promoters of ethylene biosynthesis enzyme genes through physical interactions with transcription factors. Our findings provide the basis for the practical use of sound waves to delay fruit ripening.