The distribution and incidence of Neotyphodium endophytes in native grasses from Argentina and its association with environmental factors

Abstract

We examined the occurrence of Neotyphodium endophytes in native grasses from Argentina using both herbarium material and plants collected from the field. Neotyphodium endophytes were detected in 34 out of more than 150 host species examined throughout the country. The incidence of infection was highly variable within many of the species. We examined the relationship between incidence of endophyte and environmental conditions in four host species, Bromus setifolius from Santa Cruz, Phleum alpinum and Poa rigidifolia from Tierra del Fuego and Poa bonariensis from the Pampean region. The results suggest that each endophyte-host association seems to be affected in different ways by environmental factors. B. setifolius only contained endophyte in moist rather than dry regions, while in contrast, Ph. alpinum showed the highest endophyte incidence in the driest sites. Endophyte incidence in P. rigidifolia was highest where soil fertility was high, and P. bonariensis contained the most endophyte in high pH rather than low pH soils. Field observations suggest that in poor growing conditions, such as those of the extra-Andean Patagonia, or highly acidic soils, the association is not favoured leading to a decrease in the endophyte frequency of infection or even to the complete loss of the association. Keywords: Bromus setifolius, native grasses, Phleum alpinum, Poa bonariensis, Poa rigidifolia, South America