Use of ELISA to Differentiate between Toxic and Non-toxic Endophytes in Tall Fescue Seeds

The fungal endophyte Neotyphodium coenophialum is known to enhance tolerance to biotic and abiotic stresses in grasses. However, most endophyte infected fescue contains toxic ergot alkaloids, which can induce a fescue tox icosis syndrome when consumed by ruminants and horses. Recently, new tall fescue cultivars infected with endophyte strains that do not produce toxic ergot alkaloids have been developed. The objectives of this study were to determine whether a commercially available ELISA kit for detecting ergot alkaloid (ergovaline) in plant tillers would detect alkaloids in tall fescue seeds, to determine whether mechanical scarification or crushing of tall fes cue seed would facilitate alkaloid detection by ELISA, and to determine whether ergovaline alkaloid detection by ELISA was consistent with the HPLC method. Cultivars included in the comparison were Jesup MaxQ, a proprietary tall fescue cultivar containing endophytes that do not produce ergovaline, and KY-31, a conventional cultivar containing endophytes that produce ergovaline. Seed lots of Jesup MaxQ and KY-31 had similar endo phyte infection rates of 90% and 94%, respectively, as measured by the microscopic method. Percentage seeds with ergovaline in scarified, crushed, and whole seeds were 87.5%, 91%, and 7.5%, respectively, for KY-31, and 0.5%, 0.5%, and 0%, respectively, for Jesup MaxQ, based on ELISA. The ergo valine concentration of Jesup MaxQ was < 10 ppb compared to 5290 ppb in KY-31 as determined by HPLC. The results of this study indicate that the ELISA kit was a viable alternative to HPLC for detecting the presence of ergo valine producing endophytes in tall fescue seeds. Scarifying or gently crush ing the seeds were suitable techniques for extracting alkaloids from seeds.