Welcome Bienvenu - Current research

A MOPGA (Make Our Planet Great Again) fellowship for the post-doc project of Lauren Gillespie! 2023-2024

'Mycorrhizal-like' fungi and plant nutrition: a greener way of getting required nutrients to plants

It is imperative to decrease mineral fertilizer use to reduce global warming and pollution and confront current fertilizer shortages. A promising leverage is microbial inoculants (biofertilizers) that improve plant nutrition via direct nutrient delivery from soil to roots, reducing the need for excessive mineral fertilization. Most land plants rely on arbuscular mycorrhizal (AM) symbiosis to fulfill their phosphorus (P) and nitrogen (N) nutrition, but using AM fungi as biofertilizers is challenging as they cannot be cultivated in pure cultures for large-scale inoculum production and their effectiveness can be inconsistent. Some plants have evolved new nutrient-acquisition strategies that do not rely on AM-fungi. By studying the root microbiota of one of these non-mycorrhizal (NM) plants, we discovered it can associate with culturable "mycorrhizal-like" fungi capable of providing it with enough nutrients to grow on nutrient-poor soil. Building on this, we propose to tap into the undescribed diversity of the root microbiota of NM plants living in nutrient-poor environments to uncover new mycorrhizal-like fungi and assess their potential as novel biofertilizers.

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