Newly funded! ANR JC- SymbiLoss 2022-2026
The microbiota can play major roles mediating host adaptation. Plants rely on the ancestral Arbuscular Mycorrhizal (AM) symbiosis to supplement their phosphorus nutrition. However, recent findings indicate that the AM symbiosis is not essential. Indeed, there are at least three ‘non-mycorrhizal’ plant families for which the loss of the AM symbiosis was not compensated by any major nutritional innovation that we know of. Certain non-mycorrhizal Brassicaceae were discovered to associate with new types of root endophytic fungi capable of transferring phosphorus to the plant, suggesting the existence of yet-unknown nutritional associations between non-mycorrhizal plants and their microbiota. This project aims to uncover and describe these associations by developing a novel approach to follow phosphorus in rhizosphere microbial communities. We hypothesize that non-mycorrhizal plants adapted to the loss of the AM symbiosis by establishing new nutritional microbial partnerships promoting their phosphorus nutrition.
We will be recruiting a Post-doc and a Master student on this project so contact me if you are interested!
Reconstructing P fluxes in the rhizosphere
In terrestrial ecosystems phosphorus (P) availability is among the top factors limiting plant growth and productivity. Although P is highly abundant in most soils, only a very small fraction of it (0.1-1%) is readily available for plant nutrition. There is evidence that P forms not directly available to the plant can be mobilized by certain microorganisms (archaea, bacteria, fungi and other microeukaryotes) colonizing plant roots and the surrounding soil (rhizosphere), and composing the root microbiota. Yet, the contribution of the root microbiota to plant P nutrition has received limited attention (beyond the arbuscular mycorrhizal symbiosis). Indeed, as opposed to nitrogen and carbon, there is no technology allowing the tracking of P in complex microbial communities. In this project we are developping a P tracing system to follow P movements between rhizosphere microbes and the plant.
Collaborators: Marja Tiirola, University of Jyväskylä, Finland
Funding: CNRS MITI ISOTOP project RadioNano - Coord. Juliana Almario
Non-mycorhizal plants and their root microbiota
The large majority of land plants rely on AM fungi for P acquisition, raising the question of how ‘non-mycorrhizal’ plants adapted to the loss of this symbiosis. The discovery of so-called ‘mycorrhiza-like fungi’ capable of transferring P to non-mycorrhizal plants such as Brassicaceae, points to a major role of the root microbiota and suggests the existence of yet-unknown trophic associations between plants and microbes. To uncover these associations, we are analysing the root microbiota of over 42 mycorhizal and non-mycorhizal plant species growing under natural conditions including P-starved alpine soils.
Collaborators: Wilfried Thuillier, Amelie Saillard and the ORCHAMP consortium, LECA Grenoble, France
Funding: CNRS EC2CO project MicroPhos - Coord. Juliana Almario
Phyllosphere microbiota in Arabidopsis thaliana
The Phytobiome @ LSE (Scientific breakthrough, IDEX Université de Lyon, 2019-2021) combines microbiology, developmental plant biology and chemical ecology to identify molecular signals mediating plant-microbiota associations.
Collaborators: Teva Vernoux, RDP ENS Lyon - Sylvie Baudino, LBVPAM Université de Saint Etienne