Transcriptional control of vascular proliferation

This project focusses on identifying novel factors downstream of the TMO5/LHW complex and understanding how the known players interact to control common or distinct downstream events. This is done using both forward and reverse genetics; bulk and single cell RNA sequencing approaches.

In a first instance, we are using transcriptomics approaches to identify novel players downstream of the TMO5/LHW-dependent cell proliferation. We analyzed the transcriptional responses upon simultaneous induction of both transcription factors. Using inferred network analysis, we identified DOF2.1 as a cytokinin-dependent downstream target gene. We further showed that DOF2.1 controls specific procambium cell divisions without inducing other cytokinin-dependent effects such as the inhibition of vascular differentiation. In summary, our results suggest that DOF2.1 and its closest homologs control vascular cell proliferation, thus leading to radial expansion of the root (Smet et al., (2019) Current Biology - accepted). Currently, we are investigating how other downstream factors impinge on the vascular proliferation and cell division orientation processes. Besides this approach, we have performed a forward genetics EMS screen to identify novel players in this pathway, and we are investigating the developmental specificity of the TMO5/LHW pathway.

Figure: Network generating zones of high auxin signaling in xylem cells and high cytokinin signaling in procambium cells. These also contribute to bilateral symmetry that extends to the surrounding pericycle and endodermal cells by controlling the specification of lateral root and passage cells (adapted from Wybouw and De Rybel (2018) Trends in Plant Sciences - PMID:30446307).

 

People involved in this project:

  • Brecht Wybouw (funded by FWO Odysseus type II grant)
  • Eliana Mor (funded by ERC starting grant)
  • Helena Arents (funded by PSB VIB/Ghent University)