Epichloë

Epichloë is a genus of endophytic fungi in the family Clavicipitaceae that form symbiotic associations with a wide range of grasses (Poaceae). Many species are systemic, seed-transmitted endophytes that inhabit the intercellular spaces of aerial tissues and can be passed to the next plant generation via infected seeds. They are commonly found in cool-season grasses and can influence host ecology, physiology, and interactions with herbivores.

Life cycle and transmission are variable within the genus. Some Epichloë species reproduce sexually, producing stromata on the inflorescences that can sterilize the flowers and thus choke seed production, while completing the fungal life cycle. Asexual forms, historically placed in Neotyphodium, colonize hosts without sexual structures and rely on vertical transmission through seeds. This split has blurred taxonomic boundaries, and many endophyte strains are now treated as Epichloë species regardless of their reproductive mode.

Ecology and chemistry are central to their significance. Epichloë endophytes synthesize a range of alkaloids that deter or inhibit herbivores, including ergot-like alkaloids such as ergovaline, as well as insect-deterring lolines and peramine. These compounds can enhance plant persistence and forage performance under stress and attack, but some strains also pose risks to grazing animals, causing toxicoses in livestock if contaminated forage is consumed.

Economic and agricultural aspects are notable. In pasture management, carefully selected Epichloë-endophyte associations can improve drought tolerance, disease resistance, and biomass in grasses used for forage. Conversely, the presence of toxic alkaloids in certain endophyte strains necessitates careful strain selection and monitoring to balance benefits with livestock safety. Taxonomically, Epichloë is placed in Ascomycota, Sordariomycetes, Hypocreales, Clavicipitaceae, with historical separation of Neotyphodium as an anamorphic lineage now commonly integrated under Epichloë.