Genome-Wide Analysis of the WOX Family and Its Expression Pattern in Root Development of .

Tree peony ( Andr.) is a woody plant with high ornamental, medicinal, and oil values. However, its low rooting rate and poor rooting quality are bottleneck issues in the micropropagation of . The WUSCHEL-related homeobox (WOX) family plays a crucial role in root development. In this study, based on the screening of the genome and root transcriptome database, we identified ten WOX members in . Phylogenetic analysis revealed that the ten PoWOX proteins clustered into three major clades, the WUS, intermediate, and ancient clade, respectively. The conserved motifs and tertiary structures of PoWOX proteins located in the same clade exhibited higher similarity. The analysis of -regulatory elements in the promoter indicated that genes are involved in plant growth and development, phytohormones, and stress responses. The expression analysis revealed that genes are expressed in distinct tissues. , , , and are preferentially expressed in roots at the early stage of root primordium formation, suggesting their role in the initiation and development of roots. These results will provide a comprehensive reference for the evolution and potential function of the WOX family and offer guidance for further study on the root development of tree peony.