site-cnrs sps-cnrs
Group leader: Denis Faurefr

Rhizosphere Ecology


General context: Ecology of a complex environment, the rhizosphere

We are investigating the dynamics of biological associations (bacteria-plants and bacteria-bacteria) in the complex environments that rhizosphere and soil are, as well as the impact of human activities and technologies (ex. ecological engineering, genetically modified organisms-GMOs) on the plant environment mostly in terms of bacterial diversity and activity, and resilience in soil and rhizosphere.


Figure 1: Rhizosphere of greenhouse-cultivated tobacco plants
Picture C. D’Angelo-Picard, ISV-CNRS

In the rhizosphere, communication between plant and bacteria, and between bacterial populations, often rely upon the synthesis and perception of numerous biochemical signals. Moreover, the elaborated carbon molecules released by the plant roots (the exudates) are essential to sustain the growth of bacterial populations that reach high densities in this soil compartment. This feature creates conditions for an intense communication between bacterial populations at infra- and inter-species level. Quorum-sensing (QS) is one of the cell-cell communication processes that modulate and synchronize gene expression in bacterial populations. Commonly, QS modulates bacterial functions relative to the response to the environment, the fitness of bacteria in soil and rhizosphere and their interactions with host or non-host plants.


Our project is organized along three synergic axes :

  1. The dialog between Agrobacterium tumefaciens and its host plants
    Investigations aim at analyzing the nature and role of signals, including QS signals, in the model interaction that involves A. tumefaciens and its host plants.
  2. Plants-driven modulation of bacterial interactions
    Studies undertaken in this axe deal with plants as key determinants of the structure of bacterial populations and QS-regulated functions within these bacterial populations.
  3. Ecological engineering: development and impact studies
    Investigations aim at developing and evaluating eco-technologies that target QS regulation, especially in plant pathogenic bacteria, and analyze their environmental impact.