Variation in Nitrogen Utilization in Acremonium coenophialum Isolates

Abstract

Acremonium coenophialum, a fungal endosymbiont in tall fescue, is responsible for the production of alkaloid toxins. Animals grazing endophyte-infected tall fescue often show toxicosis. In marginal environments, the endophyte is important for long-term survival of tall fescue. Few differences in endophyte isolates from individual tall fescue plants have been reported. To aid development of a toxicosis-free tall fescue, it is important to identify differences in endophyte isolates. This report describes variation in nitrogen utilization in a defined culture medium by endophyte isolates from Kentucky-31 tall fescue. Overall, the best nitrogen sources for dry weight production of mycelium were proline and potassium nitrate. Thirty-four isolates grown on agar-solidified defined media with single nitrogen sources showed variation in nitrogen utilization. Fifty percent of the isolates were unable to utilize two or more amino acids. Manipulation of endophyte variation could lead to development of a toxicosis-free tall fescue cultivar.

Adaptations of Endophyte‐Infected Cool‐Season Grasses to Environmental Stresses: Mechanisms of Drought and Mineral Stress Tolerance

“…Kulkarni and Nielsen (1986) showed that a N. coenophialum strain could assimilate NH + 4 but not NO − 3 as a source of N from the growth medium. In contrast, three out of four N. coenophialum isolates from Kentucky‐31 tall fescue analyzed by Ferguson et al (1993) could utilize NO − 3 and all of them could utilize NH + 4 as N source. Naffaa et al (1998b) examined growth of endophytes from 12 grass species of Poaceae and found that all of them (including N. lolii ) could assimilate NH + 4 but only A. chilense ‐like endophytes (a‐endophytes) could assimilate NO − 3 These results suggest a considerable variability in N utilization among endophyte isolates from different grass species.…”

Growth and Characteristics of Two Different Epichloë sinensis Strains Under Different Cultures

“…Lactose and casein are the optimal carbon and nitrogen sources for E. festucae (Li et al, 2008). Ferguson et al found that the best nitrogen sources for the mycelial growth of E. coenophiala are proline and potassium nitrate (Ferguson et al, 1993). The growth of E. festucae is significantly improved by cellulase, tryptone, casein peptone, proline, and peptone (Ma, 2009).…”