Plant and Soil

, Volume 267, Issue 1, pp 1–12

Evidence for copper binding by extracellular root exudates of tall fescue but not perennial ryegrass infected withNeotyphodium spp. endophytes


    • Texas Agricultural Experiment StationTexas A&M University
  • H. Zuo
    • Texas Agricultural Experiment StationTexas A&M University
  • D. P. Belesky
    • United States Department of Agriculture, Agricultural Research ServiceAppalachian Farming Systems Research Center
  • G. A. Alloush
    • Department of Soil Science and Plant NutritionTishreen University

DOI: 10.1007/s11104-005-2575-y

Cite this article as:
Malinowski, D.P., Zuo, H., Belesky, D.P. et al. Plant Soil (2004) 267: 1. doi:10.1007/s11104-005-2575-y


Infection of tall fescue (Festuca arundinacea Schreb.) with its endemicNeotyphodium coenophialum-endophyte (Morgan-Jones and Gams) Glenn, Bacon and Hanlin appears to reduce copper (Cu) concentrations in forage and serum of grazing animals, contributing to a range of immune-related disorders. A greenhouse experiment was conducted to identify effects of novel endophyte strains on Cu acquisition by tall fescue (Festuca arundinacea Schreb.) varieties Grasslands Flecha and Jesup infected with a novel, non ergot producing endophyte strain AR542, and two perennial ryegrass (Lolium perenne L.) varieties Aries and Quartet infected with a novel, non lolitrem B producing strain AR1, and their noninfected (E−) forms. Individual endophyte/grass associations were cultivated in nutrient solutions at 1.0 (P+) and 0.0 mM (P−) phosphorus concentrations. The Cu2+-binding activity of extracellular root exudates, and concentrations of Cu and other heavy metals in roots and shoots were measured. Extracellular root exudates of AR542-infected vs. E− tall fescue had higher Cu2+-binding activity only in P− nutrient solution as shown by lower concentration of free Cu2+ (0.096 vs. 0.188 mmol Cu2+ g−1 root DM, respectively). The Cu2+-binding activity by root exudates of perennial ryegrass was not affected by endophyte infection, but was higher (i.e., lower concentration of free Cu2+) in P− vs. P+ nutrient solution (0.068 vs. 0.114 mmol Cu2+ g−1 root DM). In this hydroponic experiment, Cu concentrations in shoots of both grasses were not a function of Cu2+-binding activity and endophyte effects on heavy metal concentrations in shoots and roots were specific for each variety. The Cu2+-binding activity of extracellular root exudates may affect Cu accumulation by field-grown, endophyte-infected tall fescue under P-limiting growth conditions and warrants verification by more specific methods.

Key words

copperFestuca arundinaceaLolium perenneNeotyphodiumnovel endophytes
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© Kluwer Academic Publishers 2004