“Living together” with Epichloë – Exploring the significance of non-plant partners in the fungal symbiotic network

The relationships between grasses and Epichloë fungi are complex and multifaceted. Moreover, additional symbiotic partners are involved in these interactions and can influence grass-fungi associations. In this article, the symbiotic partners of Epichloë are reviewed, with the mycoparasitic fungus Clonostachys epichloë analyzed as a novel, previously unconsidered element of the symbiotic network. Clonostachys epichloë fungus was first recognized as a mycoparasite of Epichloë. Further studies revealed that, in addition to its mycoparasitic activity, it also has entomopathogenic activity toward Botanophila flies involved in the sexual cycle of the Epichloë and can colonize the surface of grass seeds infected with the Epichloë endophyte, further modulating the grass- Epichloë interaction. The holistic approach to analyzing interaction networks is crucial because the natural mycoparasite C. epichloë may be used to limit choke disease in grasses caused by Epichloë fungi. By examining the effects of C. epichloë on all elements of the interaction, as well as its impact on the relationships among these elements, we can effectively assess its usefulness as biocontrol agent of Epichloë.