AMF play a pivotal role in enhancing plant nutrient uptake and fostering sustainable agriculture. However, their widespread application has been hindered by the reliance on host plants for propagation, limiting their availability. The OPT4AMF (Optimization of microbial production biostimulants with innovative additives and mycorrhizal helper bacteria) research project, in collaboration with Inoq GmbH, aims to revolutionize AMF production by pioneering plant-free cultivation techniques, thus ensuring year-round availability of AMF inoculum to support sustainable agriculture worldwide.

The primary strategy involves harnessing mycorrhizal helper bacteria (MHB) from the plant growth-promoting rhizobacteria (PGPR) genera, Azotobacter and Azospirillum, isolated from grass rhizosphere (Jena Experiment) and roots using selective media. The Azotobacter and Azospirillum genera are selected as PGPR for this study due to their ability to fix atmospheric nitrogen, enhance nutrient uptake, and stimulate plant growth through hormone production and root colonization. MHB's ability to form biofilms on AMF surfaces protects them from mycophagous bacteria and enhances their vitality. MHB strains capable of biofilm production will be evaluated for their impact on AMF spore production by testing the bacterial-fungal interaction on root organ culture (ROC) and in the absence of a plant partner.

Plant-free AMF production could revolutionize sustainable agriculture, enabling scalable inoculum production and year-round availability of these beneficial fungi. This approach supports environmentally-friendly practices by reducing reliance on synthetic fertilizers and in consequence enhancing global food security.