Influence of fungal endophyte infection on nutrient element content of tall fescue

Fungal endophytes infect several grass species. The fungus Can alter the growth, and physiological and morphological characteristics of the infected plant. A greenhouse experiment was designed to determine the effect of the fungal endophyte Neotyphodium coenophialum on the nutrient element content of a selected ecotype of tall fescue (Festuca arundinacea), when growing at two nutrient element supply levels. Stem dry matter, averaged over all harvests and nutrient element supply treatments, was higher in non-infected (E-) than in endophyte infected (E+) plants. We found a significant interaction between endophyte infection and nutrient element supply level and/or harvest date on the nitrogen (N), phosphorus (P), calcium (Ca), and magnesium (Mg) plant tissue concentrations. Only for Ca leaf concentrations the effect of infection status was not influenced by harvest date or nutrient element supply treatment and Ca concentration was higher in E- than in E+ plants. Differences between E+ and E- plants in P concentration were significant at the beginning of the experiment, and for N and Mg were observed at the end of the experiment (16 to 18 weeks). Endophyte-infected plants had higher stem N and leaf Mg concentrations in the high nutrient element supply, but significantly lower concentrations at the low nutrient element supply treatment. Phosphorus concentration in leaf and aboveground plant tissue was significantly higher in E- than in E+ plants at the high nutrient element fertility treatment at week 12, but in the low fertility treatment differences were not significant. Differences in potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) concentration between infected and non-infected plants were not statistically significant. Our results suggest that endophyte infection of tall fescue appears to increase the content of nutrient elements related to protein synthesis processes (N and Mg).

This work was supported by the Spanish Interministerial Commission of Science and Technology (CICYT) AGF96-0423. B.R. Vazquez de Aldana was supported by a research contract from the Spanish Ministry of Education and Culture and I. Zabalgogeazcoa by a postdoctoral fellowship from the lNIA.