Anne Sylvester, Univ of Wyoming, Cells at the Surface: Balancing cell division and expansion during differentiation of the maize leaf epidermis

Maize leaves emerge sequentially from stem cells around the base of the shoot apical meristem. As leaf primordia grow by cell division and expansion, a proximal-distal (P/D) developmental gradient is established along the blade to sheath axis. Epidermal cells that differentiate up the P/D gradient include the ligule and auricle, bulliform cells, stomatal complexes, and trichomes. These cell types are important physiologically because they support the primary function of photosynthesis and contribute to water use efficiency. We use the orthogonal alignment of epidermal cells as a platform for discovering gene networks required to maintain the P/D gradient and for studying mechanisms of cell expansion and leaf morphogenesis. I will present signaling pathways that we have identified to date, including a receptor-like Tyr/dual specificity kinase pathway that regulates epidermal patterning and other candidates identified through genomic approaches. Cellular and tissue parameters that contribute to leaf morphogenesis will be discussed.