Abstracts |
One of the main challenge for humanity in the years to come is represented by the production of enough food for a growing global population, while reducing the use of pesticides and chemical fertilizers and maintaining environmental quality and natural resources for future generations. The new paradigm in agriculture—sustainable intensification—may be implemented by the efficient use of practices enhancing the activity of beneficial soil microorganisms, essential elements of soil nutrient flows, at the basis of long-term soil productivity and health. Among beneficial microorganisms, arbuscular mycorrhizal (AM) fungi (AMF) have been long known for their positive impact on plant growth and health. A number of multimodal investigations showed the occurrence of diverse assemblages of bacterial communities living strictly associated with AMF spores, extraradical mycelium and mycorrhizal roots, in the mycorrhizosphere. Molecular studies confirmed the occurrence of either Mollicutes-related and unculturable endosymbionts or bacteria strictly associated with the spores of different AMF taxa, affiliated with Cellvibrio, Chondromyces, Flexibacter, Lysobacter, and Pseudomonas, Proteobacteria and Actinobacteria, and Actinomycetales, Bacillales, Rhizobiales, Pseudomonadales, Burkholderiales, including Arthrobacter, Streptomyces, Bacillus, Paenibacillus, Pseudomonas, Herbaspirillum, Massilia, Rhizobium, and Sinorhizobium. Overall, the ultrastructural and molecular studies revealed the complexity and diversity of bacterial communities living associated with AMF, suggesting putative important functional roles as plant growth promoting (PGP) bacteria and mycorrhiza helper bacteria (MHB), able to promote AMF activity and development. |