Evolution of

Plant - Microbe


Plants interact with a huge diversity of microorganisms in associations ranging from parasitic to mutualistic, with either bacteria or filamentous fungi or oomycetes.

Since plants colonized lands 450 million years ago, these associations have evolved in opposite directions. Mutualism has been maintained for hundreds of million years whereas the interactions with parasites are fast evolving.

Studying the interactions between plant lineages spanning 500 milion years of diversification and multiple microorganisms, our goals are to discover the plant molecular mechanisms behind mutualistic and parasitic interactions with microorganisms and to understand how they evolved.


Mutualism between plants and microorganisms has been essential for the evolution of terrestrial ecosystems for millions of years. It has been proposed that even the colonization of lands by plants was facilitated by a mutualistic symbiosis formed with arbuscular mycorrhizal fungi. This symbiosis, by far the most widespread in land plants, results in the accommodation of the symbiotic fungus inside the plant cells. Following this initial symbiosis, multiple other intracellular symbioses have evolved in plants as diverse as orchids, Ericaceae such as cranberry, legumes or the Jungermanniales, a group of bryophytes. Other symbiotic associations have evolved with extracellular symbionts, such as lichens in green algae and ectomycorrhizae in multiple vascular plants lineages. These symbioses provide numerous benefits, improving plant nutrient acquisition and fitness. Despite their absolute importance in terrestrial ecosystems, the molecular mechanisms underlying the origin and subsequent evolution of intracellular symbioses in plants remain poorly understood.

Our research aims at understanding how these symbiotic associations evolved. Using combinations of phylogenomics, biochemistry and genetics in multiple plants we try to determine the molecular bases of the origin, conservation and diversification of these associations.


In their constantly changing environment, plants face a large diversity of potentially pathogenic microorganisms. The ability to limit the infection by these parasites varies from species to species and, even, between accessions of a given species.

The molecular mechanisms mediating resistance have been widely studied in flowering plants. By contrast, how non-vascular plants such as liverworts defend themselves from pathogens and the genetics behind remains poorly characterized.

We aim at understanding immunity and resistance mechanisms in liverworts, by combining inter-species comparisons, reverse-genetics and Genome Wide Association Studies. We ambition to discover novel resistance mechanisms in plants.


The "Evolution of Plant - Microbe Interaction" team is located in the Plant Science Research laboratory (LRSV - www.lrsv.ups-tlse.fr), a joint unit between the CNRS and the University Toulouse III - Paul Sabatier, in Toulouse, France.