AUTHOR=Duan Lian , Hou Zhihui , Zhang Wuhua , Liang Shuang , Huangfu Minge , Zhang Jinzhu , Yang Tao , Dong Jie , Che Daidi 

TITLE=Genome-wide analysis of the WOX gene family and function exploration of RhWOX331 in rose (R. ‘The Fairy’)

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1461322

DOI=10.3389/fpls.2024.1461322

ISSN=1664-462X

ABSTRACT=<p><italic>WOXs</italic> are a class of plant-specific transcription factors that play key roles in plant growth and stress responses. However, the mechanism by which <italic>WOXs</italic> influence adventitious root development in <italic>Rosa hybrida</italic> remains unclear. In this study, <italic>RcWOX</italic> gene family in rose was identified and phylogenetically analyzed using bioinformatics analysis. A total of 381 <italic>RcWOX</italic> gene members were localized on seven chromosomes except of nine members. The main <italic>cis</italic>-acting  elements involved in hormonal, light, developmental, and abiotic stress responses were identified in the promoters of <italic>RcWOX</italic> genes, suggesting their regulation by these signals. Nine <italic>RhWOX</italic> genes had significant different expression during rooting process of rose. <italic>RhWOX331</italic>, <italic>RhWOX308</italic>, <italic>RhWOX318</italic> were positive with the formation of rose roots. RhWOX331 was positively involved in the formation of adventitious root primordia, which gene coding a transcription factor localized in the nucleus. The HOX conserved domain in the protein contributed to the self-activating activity of RhWOX331. We obtained genetically modified Arabidopsis to validate the function of <italic>RhWOX331</italic>. Overexpression of <italic>RhWOX331</italic> gene alleviated the inhibition of root length of <italic>A. thaliana</italic> primary roots by high concentration of IBA and NPA, and significantly increased the number of lateral roots on the primary roots, as well as the height of <italic>A. thaliana</italic> plants. Additionally, <italic>RhWOX331</italic> promoted adventitious root formation in A. thaliana and mitigated hormonal inhibition by exogenous 6-BA, NPA, and GA<sub>3</sub>. The <italic>RhWOX331</italic> promoter contained cis-acting elements such as ABRE, Box 4 and CGTCA-motif et.al. GUS activity analysis showed that the gene acted at the cotyledon attachment site. Taken together, these studies identified a significant expansion of the <italic>RcWOX</italic> gene family, inferred roles of certain branch members in adventitious root formation, elucidated the function of <italic>RhWOX331</italic> in adventitious root initiation, and laid the foundation for further research on the function of <italic>WOX</italic> gene family in roses.</p>