Axial Patterning of the Maize Leaf

Abstract

The characteristic morphology and anatomy of the maize leaf reflects the outcome of developmental patterning along three axes, proximodistal, mediolateral, and adaxial-abaxial, which are specified relative to the main axis of the plant. The past decade has seen a dramatic increase in our understanding of the genetic control of leaf development. Gene regulatory networks involved in the specification of organ polarity are beginning to emerge. These are distinguished by contributions of highly conserved, often redundant transcription factor families whose expression or activity are modulated to give rise to the distinctive maize leaf. Small regulatory RNAs, hormones, as well as proteins that selectively trafficking between cells have emerged as candidate signals conveying positional information within the shoot to the newly initiated leaf. This chapter outlines findings of both classical genetic and recent molecular studies that have led to a framework for axial patterning of the maize leaf.