The role of WOX1 genes in blade development and beyond

WOX1 genes have been identified in several eudicot species as important regulators of lateral organ development, and were found to control outgrowth of the blade along the mediolateral axis. However, the role of WOX1 genes in species that have compound leaves remained to be further investigated. Using a reverse genetics approach, Wang et al. (2021) analyzed WOX1 function in tomato and found that SlLAM1 loss-of-function mutants exhibit defects in leaflet development and leaf complexity. This reveals that SlLAM1 also plays a critical role in the initiation and growth of leaflets, in addition to its conserved role in blade outgrowth. Interestingly, SlLAM1 function appears also to be critical for fruit size.