Abstract

Background Prunus mume is an important woody ornamental and fruit tree of Rosaceae. Elucidating the molecular regulatory network of its flowering is of great significance for genetic improvement. The basic helix–loop–helix (bHLH) and INDETERMINATE DOMAIN (IDD) transcription factors play vital roles in plant development processes, while their regulatory cascades in Prunus mume remain largely unclear. Results This study reports a bHLH transcription factor PmbHLH130 in Prunus mume , whose transcription level responds to photoperiod, and which is predominantly expressed in leaves. Subcellular localization and transcriptional activity assays revealed that PmbHLH130 is a nuclear-localized transcriptional activator. Overexpressed PmbHLH130 significantly promotes flowering in transgenic Arabidopsis. PmbHLH130 acts downstream of several central oscillator proteins and PmIDD5, and directly activates the expression of PmCOL5 . Conclusion This study reveals that PmIDD5–PmbHLH130–PmCOL5 transcriptional cascade provides a molecular basis for understanding flowering regulation. These findings provide new insights into the molecular mechanisms of flowering control in woody plants and offer a potential framework for molecular breeding of Prunus mume .