Insights into the Biotic Factors Shaping Ectomycorrhizal Associations

Abstract

Ectomycorrhizal (EM) associations are essential symbiotic relationships that contribute significantly to the health and functioning of forest ecosystems. This review examines the biotic factors that influence EM associations, focusing on plant and fungal diversity, host specificity, and microbial interactions. Firstly, the diversity of host plants and ectomycorrhizal fungi (EMF) is discussed, highlighting how the richness of these organisms affects the formation and success of EM symbioses. Next, host specificity is explored, with a focus on the complex relationships between EMF and their host plants. Microbial interactions are examined in depth, with sections on both positive and negative influences of bacteria and different fungal groups on EM formation. Overall, this review provides a comprehensive overview of the biotic factors that shape EM associations, offering insights into the mechanisms that underpin these critical ecological interactions and their broader implications for ecosystem management and restoration.

Keywords: ectomycorrhizal; host plants; microbial interactions; plant and fungal diversity; symbioses.

Figure 1

Cross-section and diagram of a cedar root colonized by an ectomycorrhizal fungus. (a) Hartig network, (b) plant cell, (c) fungal mantle, (d) extraradical hyphae.

Figure 2

Illustration of the beneficial effects of bacteria and fungi on EM formation. EMF: ectomycorrhizal fungi; Sap-F: saprotrophic fungi; AMF: arbuscular mycorrhizal fungi.

Figure 3

Illustration of the negative effects of bacteria and fungi on EM formation. Sap-F: saprotrophic fungi; Pat-F: pathogenic fungi; AMF: arbuscular mycorrhizal fungi.