the centre for plant integrative biology

a centre for integrative systems biology funded by the BBSRC and EPSRC

Benjamin Péret

background | publications

Marie Curie Research Fellow (Intra European Fellowship)

Lateral Root Emergence

Lateral root (LR) formation is a major determinant of root systems architecture. LRs originate deep within the parental root from a small number of founder cells at the periphery of vascular tissues (Péret et al, 2009a) and must emerge through intervening layers of tissues. This process has been defined as “Lateral Root Emergence” (Péret et al, 2009b).

A schematic cross-section of the Arabidopsis root
A schematic cross-section of the Arabidopsis root

The Auxin Influx Transporter LAX3 Regulates LR Emergence

The hormone auxin, which originates from the developing lateral root, acts as a local inductive signal which re-programmes adjacent cells. Auxin induces the expression of the auxin influx carrier LAX3 in cortical and epidermal cells directly overlaying new primordia. Increased LAX3 activity reinforces the auxin-dependent induction of a selection of cell-wall-remodelling enzymes, which are likely to promote cell separation in advance of developing lateral root primordia (Swarup et al. (2008)).

A schematic of the lateral root emergence network model
A schematic of the lateral root emergence network model

A confocal microscope image of the lateral root primordia
A confocal microscope image of the lateral root primordia

Building a Regulatory Network for Lateral Root Emergence

As a Marie Curie Fellow, I interacted with CPIB modellers to build a regulatory network of lateral root emergence. This included: – developing tools to induce LR emergence and study gene expression – identifying new components of the LR emergence pathway – producing quantitative data to feed mathematical models – engineering auxin content in planta to study the spatial regulation of LR emergence – using chemical genetics to decipher LR emergence (Antoine Larrieu) – identifying important transcription factors (Wei Hseng Chan, PhD Student). As part of Strand 3, I collaborated with other aspects of LR formation such as LR patterning (Ute Voß and Mikaël Lucas).

Collaborations

  • auxin synthesis and homeostasis (Karin Ljung, Umea, Sweden)
  • nutrient regulation (Philippe Nacry, INRA Montpellier, France and Laurent Nussaume, CEA Cadarache, France)
  • biomechanical aspects (Christophe Maurel, INRA Montpellier, France and Anton Schaffner, Muenchen, Germany)
  • LR initiation (Tom Beeckman and Bert de Rybel, Ghent, Belgium)
  • LR formation (Reidunn Aalen and Robert Kumpf, University of Oslo, Norway)
  • root vascular patterning (Yka Helariutta, University of Helsinki, Finland)
  • auxin perception (Mark Estelle, University of California San Diego, USA)

Acknowledgements

This work was funded by a Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme (PIEF-GA-2008-220506).

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