Genome-Wide Analysis of WUSCHEL-Related Homeobox Gene Family in Sacred Lotus ( Nelumbo nucifera ).

WUSCHEL-related homeobox (WOX) is a plant-specific transcription factor (TF), which plays an essential role in the regulation of plant growth, development, and abiotic stress responses. However, little information is available on the specific roles of WOX TFs in sacred lotus ( Nelumbo nucifera ), which is a perennial aquatic plant with important edible, ornamental, and medicinal values. We identified 15 WOX TFs distributing on six chromosomes in the genome of N. nucifera . A total of 72 WOX genes from five species were divided into three clades and nine subclades based on the phylogenetic tree. NnWOXs in the same subclades had similar gene structures and conserved motifs. Cis-acting element analysis of the promoter regions of NnWOXs found many elements enriched in hormone induction, stress responses, and light responses, indicating their roles in growth and development. The Ka/Ks analysis showed that the WOX gene family had been intensely purified and selected in N. nucifera . The expression pattern analysis suggested that NnWOXs were involved in organ development and differentiation of N. nucifera . Furthermore, the protein-protein interaction analysis showed that NnWOXs might participate in the growth, development, and metabolic regulation of N. nucifera . Taken together, these findings laid a foundation for further analysis of NnWOX functions.