Genome-Wide Identification and Expression Profile Analysis of the WUSCHEL-Related Homeobox (WOX) Genes in Woodland Strawberry (Fragaria vesca)

The WUSCHEL-related homeobox (WOX) is a unique transcription factor family belonging to plants. Its members play important roles in regulation of plant stem cell division and differentiation or dynamic balance of the organ development. In this study, 16 Fragaria vesca WOX members (FvWOXs) were identified in the woodland strawberry (Fragaria vesca) genome. According to the phylogenetic analysis, FvWOX proteins can be classified into three clades: the ancient clade, the WUS clade and the intermediate clade. The gene structure and protein motif analysis showed that FvWOXs are highly conserved to each other in their respective clades. Chromosome location analysis revealed that FvWOXs are unevenly distributed in the Fragaria vesca chromosomes. Expression analysis showed that FvWOX genes are widely expressed in various tissues of Fragaria vesca. Moreover, when treated with 6-benzylaminopurine (6-BA) or gibberellin (GA(3)), expression level changes of the genes highly expressed in crowns were detected at 48 h after treatment. The subcellular localization of FvWUSb was determined in tobacco leaves, indicating that the protein is located in the nucleus. This study enlarged our recognition about the WUSCHEL-related homeobox genes in Fragaria vesca, and laid a foundation for further researches about this gene family in strawberry.