Molecular Systematics of Clavicipitaceae Supporting Monophyly of Genus Epichloe and Form Genus Ephelis

Abstract

The family Clavicipitaceae (Ascomycota) is comprised of fungi with perithecia borne on stro- mata, unitunicate asci, and filamentous, multiseptate ascospores. All are biotrophic symbionts, either mu- tualistic with plant hosts or pathogenic to plants, in- vertebrate animals or other fungi. Genera of plant- associated Clavicipitaceae (tribes Balansieae and Clavicipieae) are distinguished, in part, by stromal and ascus morphology, ascospore germination pat- terns, whether sclerotia are formed, and host inter- actions. Their anamorphs include enteroblastic mi- croconidial states, classified in anamorphic genera Neotyphodium and Sphacelia (for teleomorphs Atkin- sonella, Claviceps, Echinodothis, and Epichloe), and ho- loblastic macroconidia, classified in the anamorphic genus Ephelis (teleomorphs Atkinsonella, Balansia, and Myriogenospora). Epichloe' species often are mu- tualistic with grass hosts, and are ancestral to asexual, seed transmitted endophytes symbiotic with many cool-season grasses. Partial 28S nuclear rDNA se- quences were determined from isolates of five species and two undescribed mating populations of Epichloe, one asexual Epichloe hybrid (Neotyphodium coeno- phialum), and representatives of six other genera in the family. Results from phylogenetic analysis of the sequences supported monophyly of plant-associated Clavicipitaceae, with insect-pathogenic Cordyceps spe- cies more deeply rooted. Four clades were distin-