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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #253441
Title: Variable response of non-ergot-producing strains of Neotyphodium coenophialum in tall fescue to lesion nematodes

Author
item Timper, Patricia - Patty
item BOUTON, JOE - Samuel Roberts Noble Foundation, Inc

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 6/29/2010
Publication Date: 10/1/2012
Citation: Timper, P., Bouton, J. 2012. Variable response of non-ergot-producing strains of Neotyphodium coenophialum in tall fescue to lesion nematodes. In: Young, C.A., Aiken, G., McCulley, R., Strickland, J.R., Schardl, C.L., editors. Epichloae, endophytes of cool season grasses: Implications, utilization and biology. 1st edition. Ardmore, OK: The Samuel Roberts Noble Foundation. p. 40-43.

Interpretive Summary:

Technical Abstract: Tall fescue (Lolium arundinaceum) is mutualistically associated with the endophytic fungus Neotyphodium coenophialum. The fungus confers resistance to several plant pests, including some plant-parasitic nematodes, but also produces ergot alkaloids which are toxic to livestock when ingested. To alleviate the problem of ‘fescue toxicosis’, naturally occurring strains of N. coenophialum producing low to nil levels of ergot alkaloids have been artificially inoculated into elite tall fescue cultivars (novel association). In an earlier study, three of these novel strains differed from the wild-type strain in that they were unable to confer resistance to the lesion nematode (Pratylenchus scribneri). There is evidence indicating that ergot alkaloids are not involved in nematode resistance. Therefore, our objective was to test additional non-ergot strains of N. coenophialum for suppression lesion nematode populations. Nine trials were conducted with different subgroups of 24 non-ergot strains in either ‘Jesup’ or ‘KY-31’ tall fescue. Each trial included endophyte-free plants (E-free) and plants containing the wild-type (WT) strain, and seven to eight replicate pots for each endophyte status. The endophyte status of the plants was confirmed by an immunoblot assay prior to inoculation with nematodes. Nematodes were extracted from the roots 60-80 days after inoculation and counted. In eight of nine trials, nematode numbers were lower in plants with the WT strain compared to E-free plants. Eight non-ergot strains also had lower nematode numbers compared to E-free plants in at least one trial. However, the ability of these eight strains to suppress nematode numbers was not consistent among the trials. Random variation in nematode reproduction does not sufficiently explain our inconsistent results with the non-ergot strains. We suggest that some of these strains have the ability to reduce nematode numbers, but hypothesize that this ability is not stable due to the new association of the endophyte and plant genotype.