Leaf Initiation, Patterning, Organ Separation from the Meristem

Plant architecture is regulated by the activity of meristems. Lateral organs initiate from the flanks of the shoot apical meristem, a self-renewing structure at the growing shoot tip. Lateral organ boundaries, which form between the meristem and initiating lateral organs, play an essential role in organ separation and meristem maintenance. The boundary is a distinct region of limited growth; boundary cells are characterized by their small size and low rate of cell division. A number of transcription factors are expressed specifically in lateral organ boundaries. Functions of these transcription factors are not well understood. LATERAL ORGAN BOUNDARIES (LOB) encodes a conserved, plant specific transcription factor that is expressed specifically in organ boundaries. Transcriptome studies reveal that LOB regulates a diverse suite of genes. Progress toward understanding LOB function will be presented.