The art of interdigitation: Current views on pavement cell shape acquisition

Cell shape acquisition is a central feature of morphogenesis, governing tissue organization, organ development, and organismal architecture. In vascular plants, leaf epidermal cells often adopt wavy, interlocking geometries, creating intricate jigsaw puzzle-like patterns. These complex shapes, which develop from simple polyhedral progenitors, provide an excellent model for investigating the mechanisms driving cell shape acquisition. Lobed, interdigitated pavement cells contribute to planar leaf expansion and mechanical stability. Recent advances reveal that the coordination of cell wall remodeling, cytoskeletal organization, and mechanical forces underlies the emergence of lobes (outgrowths) and necks (indentations) that stabilize the tissue and support organ growth. Biomechanical models further demonstrate how spatial modulation of wall stiffness and cytoskeletal dynamics drive interdigitated growth, while phytohormone signaling and communication among neighboring cells fine-tune patterning across the epidermal layer. Here, we bring together current insights into the mechanical, molecular and signaling frameworks that shape pavement cell morphogenesis and highlight key knowledge gaps and future research directions.