The plant body is produced by two groups of stem cell, the root and shoot apical meristems. It remains largely unknown how these stem cell niches are first established in the early embryo. The proposed research will analyze the role of HAN, a predicted regulator of gene activity, in positioning the root stem cell niche. Preliminary work, largely by the methods of genetics and molecular biology, reveals that HAN determines the position of an instructive boundary between two different cell types, termed the "proembryo boundary". Signaling across this boundary, which is set up when the embryo has only eight cells, subsequently organizes the root stem cell niche. A comprehensive approach, including standard genetic and molecular biology techniques, genomics, microscopy, and biochemistry, will be followed with the aim to mechanistically understand how the proembryo boundary is established and regulated. Special emphasis will be placed on analyzing the role of HAN and closely related HAN-like factors this process. The expected results will make a significant and novel contribution to our fundamental understanding of patterning processes in plants and possibly inform targeted approaches for initiating root stem cell niches in culture. The project will lead to the training of a postdoctoral fellow and a graduate student in plant genetics, molecular biology, genomics, and advanced microscopy. Participation of high school and undergraduate students is an integral part of the research plan. Students will be recruited through programs of the Plant Biology Department, as well the University's Summer Undergraduate Research Program (SURP) and the NSF-sponsored Peach State Louis Stokes Alliance for Minority Participation (PSLSAMP).
