Fungal Endophyte Improves Survival of Lolium perenne in Low Fertility Soils by Increasing Root Growth, Metabolic Activity and Absorption of Nutrients

Background and aims: Low nutrient soil is a major limiting factor for normal growth and high yield of plants. Epichloë endophyte infection has been shown to increase host growth, nutrient uptake and balance. This study was done to determine the impact of Epichloë endophyte on growth, survival and elemental nutrient content of perennial ryegrass (Lolium perenne) under low fertility conditions. Methods: endophyte-infected and endophyte-free plants of L. perenne were grown without fertilization in a greenhouse environment. Plant survival rate, dry weight of leaves and roots, root metabolic activity and nutrient element (C, N, P, Na, K, Ca, Mg, Cu, Fe, Zn, Mn) contents were determined after 0 d, 45 d, 90 d, 135 d and 180 d. Results: The presence of Epichloë endophyte relieved the withering and yellowing of plants in the short term (0 to 90 d). The possible mechanisms by which E. festucae var. lolii infection enhances survival of plants includes improved root growth and metabolic activity (i.e., cellular metabolism), increased biomass production, and increased concentration of many nutrient elements in leaves and roots. The endophyte had positive direct and indirect effects on plants in multiple ways, including: increased organic carbon, total nitrogen, total phosphorus and Mn content in leaves, increased K content in leaves and roots, and improved root growth and activity. Conclusions: The presence of endophyte E. festucae var. lolii played a key role in improving the survival of L. perenne plants by increasing root growth and metabolic activity, promoting plant biomass and altering nutrient content.