Epichloe festucae and related mutualistic symbionts of grasses

Epichloe and Neotyphodium species (Ascomycota) are mutualistic symbionts (e ndophytes) of temperate grasses, to which they impart numerous and profound fitness benefits. Epichloe festucae, a common symbiont of Festuca, Lolium, and Koeleria spp., is a model for endophyte research that is amenable to M endelian and molecular genetic analysis. Characteristics of E. festucae inc lude: (i) production of the anti-insect alkaloids peramine and lolines, (ii ) production of the anti-vertebrate alkaloids lolitrem B and ergovaline, (i ii) efficient vertical transmission via host seeds, (iv) a mildly pathogeni c state associated with the E. festucae sexual cycle, and (v) a clear role in enhancing survival of host plants. Genetic analysis of alkaloid producti on has recently begun. Also, physiological and ultrastructural studies sugg est that signals communicated between E. festucae and host plants ensure an exquisitely balanced interaction to the mutual benefit of both partners. S everal mutualistic Neotyphodium species are hybrids between E. festucae and other endophyte species. (C) 2001 Academic Press.