The roles and performance of arbuscular mycorrhizal fungi in intercropping systems

Intercropping, which gains productivity and ecological benefits through plant facilitative interactions, is a practice often associated with sustainable agriculture. In such systems, arbuscular mycorrhizal (AM) fungi and the hyphal networks play key roles in plant facilitation by promoting connectivity, mediating interplant transfer of metabolic resources, and managing weeds, pathogens, and contaminants. This review states that the symmetrically or unsymmetrically delivered resources via AM fungi are imperative to maintain facilitative interactions between intercrops. In addition, the responses of AM fungi to intercropping are also discussed, including changes in abundance, diversity, community composition and colonization level. Although general proliferations in AM fungi via intercropping have been shown, the plant hosts and neighbors may exert different influences on AM fungi. Therefore, further research is needed in quantifying the mediating role of AM fungi on outputs of intercropping systems, clarifying the driving forces, and exploring the causation between these processes and the changes in AM fungi themselves. To conclude, the integration with AM fungi extends the understanding of key soil biological processes driving plant facilitation and will guide efforts to optimizing intercropping systems.