Genome-wide identification and expression profiling of WUSCHEL-related homeobox (WOX) genes during adventitious shoot regeneration of watermelon (Citrullus lanatus)

The WUSCHEL-related homeobox (WOX) gene family is a hotspot for diverse functions in development biology. Recently available whole-genome sequences allowed a more comprehensive analysis of WOX genes in watermelon (Citrullus lanatus). The results of this study provide a genomic framework for further research of watermelon WOX genes and contribute to understanding of the evolutionary mode of WOX genes in Cucurbitaceae crops. The qRT-PCR analysis demonstrated active expression of 11 WOX genes in watermelon tissues, which brings new evidence for WOX genes acting as conserved factors during watermelon development. Moreover, the distinct expression profiles of WOX genes during shoot initiation might lead to different shoot regeneration abilities. This work gives an overview of the differentially expressed WOX genes during shoot regeneration in watermelon. The interrelations of WOX genes, phytohormones and other transcription factors during the process will be the focus of future studies.