BZU2/ZmMUTE controls symmetrical division of guard mother cell and specifies neighbor cell fate in maize (OA) (PLOS Genetics)

Stomatal development has been studied thoroughly in the dicot model plant Arabidopsis thaliana, but stomatal development fundamentally differs between dicot and monocot for the subsidiary cells, a pair of dumbbell-shaped cells adjacent to the guard cell, formation. In this study, Wang et al., identified an EMS mutation, bzu2-1, in maize which lacks subsidiary cells and normal guard cells. Interestingly, they have found that ZmBZU2 is a basic helix-loop-helix (bHLH) transcription factor and an ortholog of AtMUTE in Arabidopsis. They show that subsidiary mother cells go through asymmetric cell division for subsidiary cell formation and they have observed the absence of SMC polarization in bzu2-1. Additionally, authors have demonstrated that ZmBZU2 moves from guard mother cell to subsidiary mother cell and regulates the expression of guard cell formation and subsidiary cell precursor initiation related genes. This work presented the role of ZmBZU2 for subsidiary mother cell polarization and the formation of guard cells in maize. (Summary by Arif Ashraf) PLOS Genetics: 10.1371/journal.pgen.1008377