Genome-wide identification, expression analyses of Wuschel-related homeobox (WOX) genes in Brachypodium distachyon and functional characterization of BdWOX12

As one kind of plant-specific transcription factors (TFs), WOX (Wuschel-related homeobox) plays an essential role in plant growth and development. In this study, 21 WOX TFs were identified in Brachypodium distachyon. They were divided into ancient, intermediate, and WUS clades based on phylogenetic analysis. These 21 BdWOX genes are mapped on 5 chromosomes unevenly. In the promoters, the most abundant cis-elements are ABRE, TGACG-motif, and G-box. qRT-PCR results showed that most BdWOX genes are expressed in vegetative and reproductive organs. Meanwhile, the expression of 14, 12, and 15 BdWOX genes are up-regulated by exogenous 6-BA, NAA, and GA, respectively. These results indicated that BdWOX genes participate in hormone signaling and regulate plant growth and development. Overexpression of BdWOX12 in Arabidopsis improved the root system, further indicating the functions of BdWOX genes in growth and development. This study provided a basis for the functional elucidation of BdWOX genes.