Deciphering sYmbiotic Networks in cArob-based MedIterranean agro-eCosystems – DYNAMIC

Task 1 - Coordination, Networking and Dissemination The task 1 covers all the coordination activities and related project management: organization, planning and control of the workplan, contractual issues, project meetings, reports, and project outputs. Task 2 - Characterization and Selection of carob-based (agro)ecosystems The task 2 deals with the survey of carob-based (agro)ecosystems and the selection of study sites in seven different countries in Europe (Italy, France, Spain), Maghreb (Morocco, Tunisia) and Near East (Cyprus, Lebanon) Task 3 - Carob genetic diversity The task 3 deals with the evolutionary history, geographical genetic structure and genetic diversity of carob populations at the Mediterranean scale Task 4 - Symbiotic microbiome diversity The task 4 aims at characterizing the symbiotic microbiome diversity associated with carob populations across the Mediterranean countries by combining NGS technologies and traditional approaches Task 5 - Ecological and symbiotic networks The task 5 deals with the integration of genetic (plant, microbiome) and environmental data for network analyses Task 6 - Ecological engineering and artificial symbiotic networks The task 6 consists in the experimental evaluation of artificial symbiotic network performances on carob growth (controlled conditions)

In progress

Improve and develop innovative researches for an efficient resource management and adaptation to global change.

Publication in journal with reading commitee (4)
1. Baumel et al 2018. Plant Ecology and Evolution, 151(2): 185-193.
2. Di Guardo et al. 2019. Tree Genetics & Genomes 15: 41.
3. Manaut et al. 2015. Ecological Engineering, 79:113-119.
4. Viruel et al 2018. Applications in Plant Sciences, 6(12): e01201.

Publication in outreach journal (1)
1. Baumel et al. 2017. La Garance Voyageuse, 118:25-29.

Oral Communications (13)
1. Khassali et al. Printemps de Baillarguet, 3-4 juin 2019, Montpellier, France.
2. Sanguin et al. Third Jack R. Harlan International Symposium, 3-7 juin 2019, Montpellier, France.
3. Sanguin H. Animation scientifique GIS-BV Interactions biotiques « La symbiose et les interactions bénéfiques plantes-microorganismes; leurs utilisations dans les sytèmes de cultures«. 06 septembre 2018, Paris, France. (invité)
4. Baumel et al. II Joint Congress on Evolutionary Biology, 19-22 août 2018.
5. Khassali et al. 5èmes Journées Francophones des Mycorhizes, 27-29 juin 2018, Dunkerque, France.
6. Mahé et al. International Conference on Ecological Sciences, 22-25 octobre 2018, Rennes, France.
7. Médail et al. Selinunte International Symposium, 28-30 juin 2018, Selinunte, Sicily. (invité)
8. Baumel et al. XXIV MEDECOS, Human driven scenarios for evolutionary and ecological changes, 31st january to 4th february 2017, Seville, Spain.
9. Médail et al. Les Rencontres de Thuret - 3eme edition, 06-07 juillet 2017, Maison des associations d'Antibes. (invité)
10. Sanguin et al. MicrobiOccitanie 2017, 24-26 avril 2017, Hotel de Région, Toulouse, France.
11. Sanguin et al. International Conference on Ecological Sciences, SFecologie2016, 24-28 october 2016, Marseille, France.
12. Viruel et al. International Conference on Ecological Sciences, SFecologie2016, 24-28 october 2016, Marseille, France.
13. Sanguin et Baumel. Atelier Prospective Biodivmex, 29 octobre au 02 novembre 2015, Saint-Michel-l’Observatoire, France.

Mediterranean terrestrial ecosystems are facing increasing desertification because of the worsening of environmental pressures due to global change. The desertification processes lead to plant cover degradation, soil erosion, nutrient depletion and a decrease of microbial activity. The establishment of global political strategies aiming at a better management of terrestrial ecosystems is thus crucial for their conservation. In this context, Ceratonia siliqua L. (carob tree), a xerophilous tree adapted to Mediterranean climate, appears as a key model for afforestation/restoration programs because of its resistance and adaptation to extreme environmental conditions and its high socio-economic added value.

Carob is a non-nodulated legume highly dependent of arbuscular mycorrhizal (AM) symbiosis for its survival and productivity. Its biological nitrogen fixation status remains uncertain but AM fungi have been hypothesized as an "obligatory vector" of nitrogen-fixing endophytic bacteria into the carob intracellular compartment. The management of carob populations is therefore closely linked to a better understanding and use (ecological engineering strategies) of the symbiotic community associated with carob.

The main hypothesis of DYNAMIC is that infra-specific plant evolutionary differentiation is a determinant, but overlooked, driver of the diversity and structure of the symbiotic community, optimizing symbiotic efficiency. However, the evolutionary history and genetic diversity structure of carob is mostly unknown at the Mediterranean scale. Geographical isolation, long term vicariance and selection for agriculture are expected to have caused extensive genetic and physiological modifications in carob, conducing to potential changes/adaptations of its associated symbiotic microbiome. The overall objective of DYNAMIC is to decipher the symbiotic network in Mediterranean carob-based (agro)ecosytems to develop innovative ecological strategies based on efficient symbiotic interactions.

The project is tackling this issue by (i) revealing the evolutionary significant units and genetic structure of carob at the Mediterranean scale, (ii) characterizing the alpha and beta taxonomic and phylogenetic diversity of carob symbiotic microbiome, (iii) exploring the links between these genetic parameters and environmental data to determine symbiotic networks and their drivers (genetic x ecological) and finally by (iv) testing experimentally the results to optimize the host-symbiont efficiency in carob tree cultures. Field investigations will be done through the carob dissemination history (native and exotic areas) and in contrasting ecological contexts (shrublands, agroforestry systems, pure stands). The symbiotic networks will be characterized by combining high-throughput molecular approaches, bioinformatic analyses based on ecological network theory, and then applied to develop innovative ecological engineering strategies.

The perspectives are a better understanding of plant-microbiome genetic relationships driving ecosystem functioning and the identification of a core and an accessory "SymbiOme" in carob populations. More generally, DYNAMIC should give new insights on the ecological drivers governing host-symbiont specificity and efficiency and should propose new avenues for the development of efficient ecological engineering strategies applied to ecosystem restoration and ecological intensification of (agro)ecosystems.