Project Summary How cell to cell signaling networks control stem cell maintenance and development is a fundamental question in biology. Cell to cell communication and stem cell maintenance are critical for human development and both contribute to disease states when disrupted. The ability to manipulate cell signaling pathways or utilize stem cells to treat human disease remain outstanding goals. As such, understanding how cell to cell signaling networks function is critical for diverse public health challenges. My lab uses the well-established and tractable model plant system, Arabidopsis, to take a multi-level approach to dissect the receptor kinase pathways that control development and stem cell proliferation. Arabidopsis offers many technical benefits which make the dissection of such signaling networks feasible. In addition, stem cell niches and other developing tissues can be monitored live in whole organisms and are easily accessible and amenable to experimental manipulation in a manner not feasible for many models. The proposal will support a series of projects that collectively aim to understand the function of peptide receptor kinase signaling in stem cell regulation and development. The projects will identify downstream components in receptor signaling pathways, examine how these pathways control cell division across diverse tissues, characterize different classes of proposed transcriptional regulators in these pathways, identify the target genes these regulators control, and examine how these pathways integrate with hormone and temperature signaling inputs. The projects will compare diverse stem cell niches and developmental processes to gain insight into how peptide signaling pathways shape divergent cellular behavior in different contexts. The proposal will train scientists at the post-doctoral, graduate, and undergraduate levels. This work will benefit from collaboration with expert groups, including a group that works on peptide receptors which function in pathogen peptide detection during immune responses, thus allowing us to compare receptor kinase signaling mechanisms across development and immunity. Ultimately, the project aims to understand these pathways at a level that will allows us to engineer novel synthetic pathway components which could be used to reprogram plant growth and even be deployed in heterologous animal systems, potentially leading to future human therapeutic applications.