Biology and applications of fungal endophytes in turfgrasses

Many grass species important to the turf industry are commonly infected by fungal endophytes belonging to the Ascomycete family Clavicipitaceae. The term endophyte refers to the characteristic distribution of hyphae in the intercellular spaces of above-ground plant parts, such as the leaf sheath, floral stems, and seeds. The genus Epichloe, with anamorphs in Neotyphodium, is the most frequently studied group of the clavicipitaceous grass endophytes. In some grass endophytes, the sexual cycle is completely reduced, and they develop a systemic and asymptomatic infection during the entire life cycle of the host. In this case, the fungal endophyte and seed disperses together (e.g., Neotyphodium spp. on tall fescue and perennial ryegrass). In other cases, the fungal endophyte may cause total or partial sterilization of the host, producing stromata on the developing inflorescence and aborting the seeds. Currently, turf breeding programs continue to incorporate beneficial endophytes into germplasm to improve turfgrasses.