Identification and characterization of WUSCHEL-related homeobox (WOX) gene family in economically important orchid species Phalaenopsis equestris and Dendrobium catenatum

Orchids are diverse and economically important ornamental plants with mesmerising floral morphology and extended flower longevity. Recent whole genome sequencing of the selected orchids enabled genome-wide characterization of various gene families with economic importance. WUSCHEL-related homeobox (WOX) transcription factors are plant specific homeobox proteins, which participate in multiple developmental activities, especially during embryogenesis, organogenesis and florogenesis. In the present study, a total of 14 WOX genes were identified in Phalaenopsis equestris and 10 from Dendrobium catenatum. The phylogenetic analysis and protein characterization revealed the conserved nature of WOX proteins in both the species. However, PeWOX and DcWOX genes differed in their exon-intron organization. Three gene duplication events were predicted in P. equestris whereas no such event was found in D. catenatum. Majority of WOX genes were tissue specific, while certain genes showed expression in all developmental stages. It was also observed that the expression of WOX genes was comparable among orthologs. The expression pattern matched the cis-regulatory promoter elements predicted in the upstream region. The present study unfurls the potential for functional characterization of selected WOX genes in heterologous system and in planta.