Role of moss and Arabidopsis zinc-finger homeodomain transcription factors in regulating plant architecture

Zinc-finger homeodomain transcription factors (ZF-HD TFs) are relatively a small gene family in Arabidopsis involved in plant development and stress response. However, the biological functions of ZF-HD TFs remain largely undiscovered. Here, we aimed to elucidate the evolutionary history and functional role of ZF-HD TFs in other species, by performing phylogenic analysis and domain and motif identification studies in Arabidopsis, sorghum (Sorghum bicolor), and moss (Physcomitrella patens). Forty-two ZF-HD TF proteins were classified into two distinct subfamilies based on the conserved ZF Cys/His-rich dimerization and homeodomain (HD) domains. The phylogenetic tree of proteins was further divided into five groups based on the similarity of sequences, and three distinct motifs were defined in the amino acid sequences. Genetic analysis revealed that the moss PpZF-HD1, Pp3c1_15290, gene partially rescued the amiR zf-HD-79 mutant lines at phenotypic and molecular levels. Subcellular localization studies revealed that moss PpZF-HD1 was localized in the cytosol and nuclei. Phylogenetic analysis and genetic complementation revealed that ZF-HD TFs play functional roles in regulating plant architecture, which is conserved in Arabidopsis, sorghum, and moss. Although our study is only a preliminary exploration into ZF-HD TFs, it provides a novel perspective that will help future researchers better understand the biological role of ZF-HD proteins in plants.