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.