Regulates Lateral Branch and Leaf Development in Barley.

The shoot apical and axillary meristems control shoot development, effectively influencing lateral branch and leaf formation. The barley () () mutation blocks axillary meristem development, and mutant plants lack lateral branches (tillers) that normally develop from the crown. A genetic screen for suppressors recovered two recessive alleles of () that partially rescued the tillering phenotype. Mutations in produce shorter plants with fewer tillers and disrupt the leaf blade-sheath boundary, producing liguleless leaves and reduced secondary cell wall development in stems and leaves. is predicted to encode an unannotated protein containing an RNaseH-like domain that is conserved in land plants. transcripts accumulate at the preligule boundary, the developing ligule, leaf margins, cells destined to develop secondary cell walls, and cells surrounding leaf vascular bundles. Recent studies have identified regulatory similarities between boundary development in leaves and lateral organs. Interestingly, we observed transcripts at the preligule boundary, suggesting that contributes to boundary formation between the blade and sheath. However, we did not observe transcripts at the axillary meristem boundary in leaf axils, suggesting that is not involved in boundary development for axillary meristem development. Our results show that contributes to leaf and lateral branch development by acting as a boundary gene during ligule development but not during lateral branch development.