Genome wide characterization of WUSCHEL-related homeobox (WOX) gene family in Apostasia shenzhenica, a primeval orchid

Abstract

In the present study, we report identification and characterization of the plant-specific WUSCHEL-related homeobox (WOX) gene family in Apostasia shenzhenica, a primeval orchid. WOX proteins are DNA-binding WUSCHEL-related homeobox (WOX) encoding transcription factors that play critical role in zygote patterning, embryo development, organogenesis, florigenesis, stress responses etc. Ten putative AsWOX genes were predicted in the A. shenzhenica genome and were characterized by the presence of DNA-binding helix-loop-helix-turn-helix motif. AsWOX proteins were grouped into three clades, ancient, intermediate and WUS on the basis of sequence homology with Arabidopsis thaliana (AtWOX), Oryza sativa (OsWOX), Phalaenopsis equestris (PeWOX) and Dendrobium catenatum (DcWOX) and their phylogenetic relationship was established. Gene structure analysis revealed that three AsWOX genes had two introns, six genes had a single intron, and one gene was intron-less. Expression profiling in a variety of tissue (tubers, seeds and pollens) was analysed in light of the presence of specific cis-regulatory elements in the promoter region and their role in various developmental processes was discussed. Three dimensional structures were predicted for three selected AsWOX proteins representing the three clades. The present study provides insights to the role of AsWOX gene family in various vital developmental processes, establishes phylogenetic relationships with related plant species and provides a platform for functional validation of specific AsWOX genes.