family genes in wheat ( L.): Evolutionary conservatism, functional diversification, and active expression in abiotic stress.

Plant homeodomain (PHD) transcription factors (TFs) are a class of proteins with conserved Cys4-His-Cys3 domains that play important roles in plant growth and development and in response to abiotic stresses. Although characterization of has been performed in plants, little is known about their function in wheat ( L.), especially under stress conditions. In the present study, 244 TaPHDs were identified in wheat using comparative genomics. We renamed them based on their chromosomal distribution, and almost all PHD proteins were predicted to be located in the nucleus. According to the unrooted neighbor-joining phylogenetic tree, gene structure, and motif analyses, genes were divided into four clades. A total of 149 genes were assigned to arise from duplication events. Furthermore, 230 gene pairs came from wheat itself, and 119, 186, 168, 7, 2, and 6 gene pairs came from six other species (, , , , and , respectively). A total of 548 interacting protein branches were identified to be involved in the protein interaction network. Tissue-specific expression pattern analysis showed that were highly expressed in the stigma and ovary during flowering, suggesting that the gene plays an active role in the reproductive growth of wheat. In addition, the qRT-PCR results further confirmed that these genes are involved in the abiotic stress response of wheat. In conclusion, our study provides a theoretical basis for deciphering the molecular functions of , particularly in response to abiotic stress.