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Study of the diversity of Frankia symbionts and the nitrogen cycle associated with alder trees in the wetlands of 'Dombes'  in a context of climate change.

Funding: E2M2 Gwennaëlle HENRY ministerial grant (2023-2026), supervisors: Sandra KIM TIAM ; Amélie CANTAREL ; Aude HERRERA-BELAROUSSI. Partner: Fondation Pierre Vérots (https://www.fondation-pierre-verots.fr/)

This project focuses on the impact of global change on the diversity of microbial players in the nitrogen cycle associated with alder trees in the wetlands of 'Dombes'. More specifically, it aims to (i) describe the effect of host (A. glutinosa versus A. cordata) on the diversity of associated Frankia populations, rhizospheric microbial communities and their functions in relation to the nitrogen cycle, (ii) understand how alder trees can influence the microbial players involved in the nitrogen cycle, and (iii) assess the capacity of A. cordata to fulfill the ecological function of nitrogen fixer under conditions of soil drying.

Immune system of alder trees in symbiosis with Frankia, against the pathogen Phytophtora.

Funding: E2M2 Mathilde VINCENT ministerial grant (2020-2023), supervisors: Aude HERRERA-BELAROUSSI, Anne-Emmanuelle HAY, Hasna BOUBAKRI ; EC2CO IMMUNOD project (CEA-Marcoule collaboration)

• Assessment of Frankia's impact on the alder's immune response and hence on plant/pathogen interactions.
• Would the plant's defense system be kept active following nodulation by Frankia, thus strengthening its immune response and enabling it to better protect itself against pathogens?

Host compatibility/incompatibility during the Alnus/Frankia symbiosis: metabolomic responses of Frankia to the alder secretome.

Funding: Bonus Qualité Recherche Accueil EC 2021 and EC 2022 projects (Sandra KIM TIAM)

This project aims to study host compatibility/incompatibility relationships during the Alnus/Frankia symbiosis through (i) the in silico identification of characteristic genes of infective and non-infective Frankia strains of A. glutinosa via a comparative genomics approach and (ii) the in vivo characterization of the effect of the A. glutinosa root secretome on an infective strain and a non-infective strain via an untargeted metabolomics approach.

Functions of antimicrobial peptides (AMPs) in the Alnus/Frankia symbiosis.

Funding: E2M2 Mélanie GASSER ministerial grant (2018-2021), supervisor: Hasna BOUBAKRI; EC2CO DiFoPep program (Hasna BOUBAKRI, Petar PUJIC, Philippe NORMAND, Biopark Archamps collaborations).

AMPs are known to be involved in the defense mechanisms of eukaryotes against pathogens. Here, we focus on the roles of AMPs in Alnus in symbiosis with Frankia.

• Global repertoire of AMPs: from Alnus genome, hundreds of peptides belonging to around ten classes (LTP, defensins, etc.) have been identified, some of which are overexpressed in alder cells after 64h of contact with Frankia (first contact). The aim is to characterize these peptides and their expression using various omics approaches (bioinformatics, transcriptomics, proteomics...).
• Targeted study: by targeting "defensin-like" and "Lpid Transfer Protein" peptides, investigations are being carried out to identify their physiological functions.