Plant-Growth Promoting Bacteria and Arbuscular Mycorrhizal Fungi from North Africa for Applications in Arid and Semi-arid agroecosystems

Anthropogenic activities negatively impact soil fertility, biodiversity, and ecosystem services. Beneficial soil microorganisms, notably plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF), represent a sustainable strategy to strengthen soil resilience, plant growth, and productivity. This thesis, within the PRIMA project ProSmallAgriMed, aims to support sustainable farming in arid and semi-arid regions by improving water-use efficiency, conserving soil, and enhancing fertility. The approach combines beneficial microbiota with intercropping of Opuntia ficus-indica and Sorghum bicolor, promoting conservation agriculture for smallholders under extreme conditions.Root samples of Opuntia were collected in Morocco across humid, semi-arid, and arid sites. From rhizospheric soil, 77 bacterial strains were isolated and screened for plant growth-promoting traits (phosphate solubilization, nitrogen fixation, indole acetic acid, siderophore and ammonia production, antifungal activity, and water stress tolerance). Promising strains were further characterized through 16S rRNA sequencing, ACC deaminase activity, and antibiotic susceptibility testing. AMF spores were isolated from Algeria and Tunisia, identified using LSU rDNA sequencing, and propagated for inoculum preparation. Additional tests used Italian AMF on Opuntia, assessing biomass and early development. PGPB isolates were also evaluated on Sorghum through germination assays, root growth, and biomass production, alongside compatibility tests to design microbial consortia. The study highlights the complementary roles of PGPB and AMF in enhancing plant resilience, biomass, and productivity, offering a foundation for sustainable agriculture in arid and semi-arid regions.