Abstract

Anthocyanins are vital secondary metabolites in plants, playing key roles in defending against diverse biotic and abiotic stresses. WRKY transcription factors are known to participate in stress-induced anthocyanin accumulation; however, the mechanism by which WRKY transcription factors regulate anthocyanin biosynthesis in rose (Rosa chinensis) remains unreported. In this study, we identified RcWRKY71, a Group IIc WRKY transcription factor containing the conserved WRKYGQK heptapeptide and a C2H2-type zinc finger motif. Subcellular localization analysis revealed that RcWRKY71 is localized in the nucleus and possesses transcriptional activation activity. Functional characterization demonstrated that RcWRKY71 promotes anthocyanin accumulation in rose petals and enhances drought tolerance. Further mechanistic studies showed that RcWRKY71 activates anthocyanin biosynthesis by directly binding to the promoters of three R2R3-MYB transcription factors: RcMYB1, RcMYB113c, and RcMYB114a. Additionally, RcWRKY71 forms homodimers via its leucine (Leu) zipper domain, which is essential for its functional enhancement. Our findings reveal a novel regulatory mechanism by which WRKY transcription factors modulate anthocyanin accumulation and confer drought resistance in rose, highlighting the role of Leu zipper-mediated homodimerization in enhancing transcriptional activity.