Evidence supporting the occurrence of a new species of endophyte in some South American grasses

Endophytes of several South American grasses were examined. The taxonomic s tatus of endophytes in Festuca argentina, F. hieronymi, Poa huecu, and an u nidentified species of Poa is evaluated. On the basis of morphological feat ures, and rDNA and protease gene sequence data, it is proposed that this en dophyte is different from several other endophytes examined from North Amer ican, South American, and European species of Festuca and Pen. These endoph ytes, believed responsible for causing the 'tembladera' or 'huecu' toxicosi s in animals, have also been reported to produce unique toxins. Isozyme ana lysis supports the distinctness of these endophytes but also demonstrates v ariability in populations with respect to gene polymorphisms. Taking all th e data into consideration, we propose to establish a new endophyte species Neotyphodium tembladerae which includes endophytes found in multiple grass species. We suggest the use of a phylogenetic species concept to define spe cies of Neotyphodium.