Neotyphodium in Native Populations of Arizona Fescue

Abstract

The discovery of the anti-herbivore properties of Neotyphodium endophytes, most of the available literature suggests that these endophytic fungi are plant defensive mutualists, and ecologists have readily extrapolated it to all endophyte-plant interactions (Breen 1994, Clay 1990). The current understanding of the mutualistic nature of endophytes is, however, dominated by studies of a few cultivars of two introduced and selectively bred agricultural grass species, tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) using non-native vertebrate grazers or herbivorous insects. Many other grass species harboring the Neotyphodium endophytes are shown either not to produce mycotoxins or composition of produced mycotoxins varies (Siegel et al., 1990). Thus we propose that plant-endophyte interactions might be much more complex in native grasses under natural conditions than in the agricultural arena of selectively-bred, non-native pasture grasses described in past studies.