Vascular Pattern Formation in Leaves of Arabidopsis

Yale University, New Haven CT

Investigators

Abstract

Timothy M. Nelson IOS-1021188 Vascular pattern formation in leaves of Arabidopsis This project seeks to understand the patterning and activities of provascular (PV) cells and procambial cell (PC) files, which are successive stages in the formation of leaf vein networks. A spatial patterning role for auxin signaling and polar auxin transport (PAT) has been demonstrated recently in many developmental processes, such as the initiation of leaves and the patterning of veins. However, each case of auxin patterning relies on a distinct context - certain cells and certain pathways within them are made auxin-responsive in a manner unique to that process, at the right time and place in development. That is, there are process-specific features both upstream and downstream of auxin's role. Prior results from this project suggest that specific sterols regulate pattern formation for leaf veins. This project will use genetics, cell biology and biochemistry to test the hypothesis that specific sterol molecules provide a connection between cellular spatial information in developing leaf tissue and the PAT machinery that facilitates vein patterns. The results would reveal (1) the regulation of the PAT process by specific sterol molecules, (2) the regulation of genes for sterols and sterol-binding proteins in vein-forming regions, and (3) the identity of vein patterning genes that are affected by specific sterols. As understanding of vein patterning and differentiation increases, it will provide a means of influencing development, pathogenesis defense, and physiology (e.g., C4 photosynthesis, resource allocation, nutrient uptake, drought tolerance, etc.), all of which depend on leaf veins. This project serves as a training vehicle for students, postdoctoral scientists, and minority summer research interns. The project is a source of illustrations for the PI's teaching of biology to non-science undergraduates, many of whom have interest in working on science policy and science & society issues.