Molecular Mechanisms Driving Switch Behavior in Xylem Cell Differentiation
Gina M. Turco,
Joel Rodriguez-Medina,
Stefan Siebert,
Diane Han,
Miguel Á. Valderrama-Gómez,
Hannah Vahldick,
Christine N. Shulse,
Benjamin J. Cole,
Celina E. Juliano,
Diane E. Dickel,
Michael A. Savageau,
Siobhan M. Brady
Affiliations
Gina M. Turco
Department of Plant Biology and Genome Center, University of California, Davis, Davis, CA 95616, USA
Joel Rodriguez-Medina
Department of Plant Biology and Genome Center, University of California, Davis, Davis, CA 95616, USA
Stefan Siebert
Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
Diane Han
Department of Plant Biology and Genome Center, University of California, Davis, Davis, CA 95616, USA
Miguel Á. Valderrama-Gómez
Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
Hannah Vahldick
Department of Plant Biology and Genome Center, University of California, Davis, Davis, CA 95616, USA
Christine N. Shulse
Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
Benjamin J. Cole
Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
Celina E. Juliano
Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
Diane E. Dickel
Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
Michael A. Savageau
Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA 95616, USA; Department of Biomedical Engineering, University of California, Davis, Davis, CA 95616, USA
Siobhan M. Brady
Department of Plant Biology and Genome Center, University of California, Davis, Davis, CA 95616, USA; Corresponding author
Summary: Plant xylem cells conduct water and mineral nutrients. Although most plant cells are totipotent, xylem cells are unusual and undergo terminal differentiation. Many genes regulating this process are well characterized, including the Vascular-related NAC Domain 7 (VND7), MYB46, and MYB83 transcription factors, which are proposed to act in interconnected feedforward loops (FFLs). Less is known regarding the molecular mechanisms underlying the terminal transition to xylem cell differentiation. Here, we generate whole-root and single-cell data, which demonstrate that VND7 initiates sharp switching of root cells to xylem cell identity. Based on these data, we identified 4 candidate VND7 downstream target genes capable of generating this switch. Although MYB46 responds to VND7 induction, it is not among these targets. This system provides an important model to study the emergent properties that may give rise to totipotency relative to terminal differentiation and reveals xylem cell subtypes. : Turco et al. demonstrate that VND7 initiates sharp switching of root cells to xylem cell identity. The authors identify four candidate VND7 downstream target genes capable of generating this switch. This work provides a framework for models that give rise to totipotency relative to terminal differentiation. Keywords: xylem, single cell, totipotent, differentiation, switch, single cell
