Plant-associated fungi in the rhizosphere are incredibly diverse.

High plant diversity promotes fungal diversity and can suppress soil fungal pathogens.

Many mycorrhizal and endophytic fungi are effective biocontrol agents for plants.

Pathogen biocontrol is frequently associated with both fungal communities and individual microorganisms.

New diagnostic tools are revolutionising fungal pathogen detection in the soil and rhizosphere.

Plant-associated fungi are incredibly diverse, comprising over a million species of mycorrhiza, endophytes, saprophytes and pathogens worldwide. This diverse fungal community is highly important for plant health. Many fungi are effective biocontrol agents that can kill or suppress fungal pathogens, with pathogen biocontrol found for both individual microorganisms and plant-associated fungal consortia. Meanwhile, increased plant community diversity aboveground corresponds to an increase in below-ground fungal community diversity, which contributes in turn to improved rhizosphere soil health and pathogen suppression. In this review, we discuss the role of fungal diversity in soil health and plant disease suppression and the various mechanisms by which mycorrhizal and endophytic fungi combat plant pathogenic fungi. We also discuss the array of diagnostic tools, both well-established and newly developed, which are revolutionising fungal pathogen detection and rhizosphere community analysis.

© 2022 The Authors. Published by Elsevier Ltd.