The peach NAC transcription factor SMB-LIKE1 (PpeSML1) integrates hormonal signaling to trigger senescence and chlorophyll degradation during fruit abortion.

Fruit abortion represents a significant challenge in horticulture, leading to reduced yields and compromised fruit quality. This study explored the mechanisms underlying fruit abortion in peach, with a particular focus on the role of the NAC transcription factor (TF) SMB-LIKE1 (PpeSML1). RNA-Seq analysis and functional assays revealed that PpeSML1 promotes senescence and inhibits growth by activating pathways related to chlorophyll degradation and stress responses. Overexpression of PpeSML1 in Arabidopsis, combined with transient overexpression assays in tobacco leaves and peach shoots, confirmed its role in growth inhibition and early senescence induction. Hormonal analysis demonstrated that abscisic acid (ABA) and indole-3-acetic acid (IAA) regulate the expression of PpeSML1 through PpeABR1 and PpeHB7, thereby linking hormonal signaling to fruit abortion. Furthermore, gene expression profiling and dual luciferase assays identified downstream targets of PpeSML1, including PpeNYE1 (involved in chlorophyll breakdown) and senescence-associated regulators PpeBFN1 and PpeBRN1. These findings reveal a novel molecular pathway involved in fruit abortion and provide potential targets for enhancing fruit retention in peach production.