Microbial diversity associated with the argan tree and its functional and biotechnological potential

Argania spinosa, a monotypic and endemic tree species native to Morocco, is far from an ordinary plant. It is a keystone species in semi-arid agroecosystems, valued for its ecological, socio-economic, and heritage importance. Its exceptional performance under adverse conditions suggests that the microorganisms associated with it are equally robust and functionally versatile. This review synthesizes current knowledge on bacteria, filamentous fungi, and yeasts associated with argan trees from both natural arganeraies and nursery-grown seedlings. These microorganisms enhance nutrient acquisition, stress tolerance, pathogen suppression, and seedling establishment. Bacterial communities, particularly plant-growth-promoting rhizobacteria, contribute to phosphate solubilization, hormone modulation, biocontrol, and the production of industrially relevant compounds such as polyhydroxybutyrate. Among the isolated genera, Streptomyces was the most frequently reported. Fungal communities are dominated by arbuscular mycorrhizal fungi, which support phosphorus uptake and drought resilience, while endophytic Ascomycota, selected Basidiomycota, and entomopathogenic fungi provide additional functional diversity and potential for biocontrol. Yeasts, although less studied, may possess unexplored metabolic traits with applications in agro-food and biotechnological processes. Microbial diversity is strongly influenced by both the isolation environment and the identification methods, from culture-based techniques to high-throughput sequencing and metagenomics. Understanding the ecology and functional potential of argan-associated microorganisms offers opportunities for sustainable argan forest restoration, climate-resilient agroecosystems, and innovative biotechnological applications. By linking the performance of this emblematic tree to the potential of its associated microbiome, this review highlights a largely untapped resource for advancing dryland agriculture and biotechnological innovation.