The Mycorrhizae and Mediterranean Ecosystems Group (MYCOMED), the African Network on Mycorrhiza (AFRINOM) and the French Mycorrhizologist Network (RAMYF) co-organized an International Congress on "Mycorrhizal Symbiosis a Key Factor for Improving Plant Productivity and Ecosystems Restoration" in Marrakech, Morocco, October 15-17, 2014. Three hundred participants from 45 different countries attended the congress, which included 65 oral presentations and 100 posters. Abstracts of all talks and posters can be found at the website (http://icmycorrhizae2014. uca.ma) of Cadi Ayyad University. The congress was an international forum for exchange of knowledge and expertise between scientists developing fundamental and applied mycorrhizal research as well as companies commercialising mycorrhizal inoculum. The objectives were to update scientific and technical knowledge on mycorrhizal fungi as providers of key ecological services, to valorize the mycorrhizal symbiosis in practices in the socio-economic environment of Mediterranean and tropical areas, and to share the experiences of scientists with young researchers, policy makers and end-users. The contents addressed included three topics: (i) biology, ecology and diversity of mycorrhizal fungi in tropical and Mediterranean environments, (ii) mycorrhizal symbiosis and plant tolerance to biotic and abiotic stresses, (iii) valorization and transfer of mycorrhizal biotechnologies in agro-ecological engineering strategies and the socio-economic environment of tropical and Mediterranean areas.