Rhizogenesis Lab - Projects ................................
Modelisation of auxin transport and root branching in Arabidopsis
Dr. Christian Jay-Allemand - Mikaël Lucas
In this work, our aim is to understand the genetic and physiological determinants of axillary root initiation in Arabidopsis thaliana.
As in the case of primordia initiation of the shoot apical meristem,
auxin plays a crucial role in root initiation. Organ initiation is
correlated to high concentrations of auxin. However, in both systems,
organ initiation is very different. In particular, in the root
development, lateral organs initiation is observed at a long distance
from the root meristem, with no apparent spatial or temporal structure.
Our main assumption is that this system is governed by a mechanism of competition for auxin while the root system is developing.
To understand this complex dynamic interaction, we develop a sink-source dynamic model
of the root system development in which the transport of auxin is
controlled by active carriers of the PIN family (a first prototype has
been developed using L-Systems). First experimental protocols were carried out on Arabidopsis thaliana, with accuracy ranging from macroscopic to cellular levels.
We obtained complete data about the developmental sequence
in the primary root and its laterals. This extensive database is
explored using tools for sequence analysis (distance between sequences,
different types of Markovian models). First results show structures and
correlations between positions and stages of development of lateral
organs which can now be exploited for the design of the dynamic model.
This work is done in collaboration with Virtual Plants.