Systematic analysis of WOX transcription factor family in the biodiesel tree Lindera glauca and functional characterization of LgWOX24 in root development

The WUSCHEL-related homeobox (WOX) gene family is vital for plant growth and development. Despite its importance, more research is needed on the WOXs in economically significant species like Lindera glauca, a tree with oil-rich fruits and potential as a biodiesel feedstock. Understanding the WOX family in L. glauca could enhance its economic value, yet a comprehensive analysis is needed, leaving a gap in our knowledge of these genes' roles. Here, we performed a genome-wide analysis to identify and characterize the WOX family in L. glauca. We identified 30 LgWOXs, categorized into three clades. Sequence alignment confirmed that these LgWOX proteins have a conserved structure, suggesting similar functions. Synteny and chromosomal distribution analyses indicated that both whole-gene and segmental duplications contributed to the expansion of the LgWOX family. Expression pattern analysis revealed that LgWOX3 and LgWOX24 are predominantly expressed in L. glauca roots, indicating a role in root development. Transient overexpression of LgWOX24 resulted in reduced expression of genes related to hormone polar transport and increased levels of abscisic acid regulators, suggesting that LgWOX24 negatively regulates root growth. These findings provide insights into the roles of WOXs in L. glauca, particularly in root development. By elucidating the function of LgWOX24, this study lays the groundwork for future bioengineering efforts to optimize root growth, potentially enhancing L. glauca's utility as a biodiesel feedstock and its broader agricultural applications.