Genome-Wide Identification of WUSCHEL-Related Homeobox Gene Family and their Expression Analysis During Somatic Embryogenesis in Oil Palm (Elaeis guineensis)

WUSCHEL-related homeobox (WOX) genes have been shown to play important roles in the regulation of gene transcription involved in the early phases of embryogenesis. In this study, a total of 15 EgWOXs were identified from the oil palm genome and their physicochemical properties were analyzed. Phylogenetic analysis divided 15 EgWOXs into three different clades i.e. modern, ancient, and intermediate. EgWOXs contain ten conserved motifs and two conserved domains. Further, cis-acting elements analysis identified the presence of light, stress, and phytohormone responsive elements in the promoter regions of EgWOXs. RNA-seq analysis of EgWOX genes in different embryogenesis stages of oil palm embryogenic callus (EC), non-embryogenic callus (NEC), and somatic embryo (SE), indicated the significant expression of EgWOXs in EC and SE stages. Real-time PCR analysis results showed the significant expression of EgWOX2, EgWOX7, EgWOX8, EgWOX9, and EgWOX12 genes in somatic embryogenesis stage, indicating their roles in regulating oil palm somatic embryogenesis.