PsWRKY71 acts as a GA signaling component to promote bud break in tree peony (Paeonia suffruticosa).

Tree peony (Paeonia suffruticosa) is an important garden plant with high ornamental and economic value. Bud endodormancy release is prerequisite for bud break, which affects its flowering time and quality, and activating gibberellin (GA) signaling is a key factor in this process. The DELLA protein PsRGL1 negatively regulates bud break, but its interacting transcription factors and their roles remain largely unexplored. Here, we identified a direct interacting partner of PsRGL1, PsWRKY71, using yeast two-hybrid, pull-down, and luciferase complementation assays. PsWRKY71 was significantly induced by both chilling and exogenous GA3 treatments. Functional studies showed that PsWRKY71 promoted bud break and upregulated the expression of bud-break-related genes. RNA-seq and subsequent analyses revealed that PsWRKY71 directly bound W-box elements of the PsCYCD6.1 promoter to activate its expression. Notably, PsRGL1 inhibited the DNA-binding ability and transactivation activity of PsWRKY71. Furthermore, overexpression of PsCYCD6.1 increased the proportion of S-phase cells and subsequently accelerated bud burst. Our results demonstrated that PsWRKY71 acts as a positive regulator of bud break by accelerating cell proliferation and integrating it into the GA signaling pathway by interacting with PsRGL1. These findings elucidate a GA pathway, PsRGL1-PsWRKY71-PsCYCD6.1, which enriches the mechanism of bud break in tree peony.