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United States Department of Agriculture

Agricultural Research Service

Title: Response of Pratylenchus Spp. in Tall Fescue Infected with Different Strains of the Fungal Endophyte Neotyphodium Coenophialum

Authors
item Timper, Patricia
item Gates, Roger - SOUTH DAKOTA STATE UNIV.
item Bouton, Joe - UNIVERSITY OF GEORGIA

Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 11, 2004
Publication Date: July 1, 2005
Citation: Timper, P., Gates, R.N., Bouton, J.H. 2005. Response of Pratylenchus spp. in tall fescue infected with different strains of the fungal endophyte Neotyphodium coenophialum. Nematology. 7(1):105-110.

Interpretive Summary: The presence of an endophyte (an internal fungus) in tall fescue confers resistance to some plant-parasitic nematodes, but also results in the production of ergot alkaloids which are toxic to livestock. Recently, new strains of this endophyte have been isolated from wild tall fescue and artificially inoculated into elite tall fescue cultivars. These strains produce low to nil levels of ergot alkaloids and are referred to as non-ergot strains. Our objective was to determine whether non-ergot strains of the endophyte confer the same level of resistance to lesion nematodes as the endemic strain in tall fescue. In a greenhouse experiment, nematode reproduction was compared in two fescue cultivars (Jesup and Georgia 5) infected with either the endemic strain (E+), or two non-ergot strains AR542 and AR584. An additional non-ergot strain, AR514, was tested only in Jesup. Georgia 5 and Jesup without endophytes (E-) were used as controls. The endophtye status of the plants was confirmed and then three plants per cultivar/endophyte combination were transplanted into 10-cm square pots. The pots were inoculated with lesion nematodes. After 8 weeks, the number of nematodes within the roots from each pot was determined. Reproduction of the nematodes in either Georgia 5 or Jesup containing the non-ergot strain AR542 was not different from reproduction in E- plants. AR514 also did not confer resistance to the nematodes in Jesup. The non-ergot strain AR584, on the other hand, appears to confer resistance to lesion nematodes in Georgia 5, but not in Jesup; though, the level of resistance in Georgia 5 was less than the resistance conferred by the endemic endophyte. Genetic differences between the two tall fescue cultivars may affect growth of the endophyte or production of a nematode toxin or deterrent by the endophyte. Because only a small subset of endophyte strains have been tested, we are screening additional non-ergot strains for resistance to lesion nematodes.

Technical Abstract: The presence of the endophyte Neotyphodium coenophialum in tall fescue (Festuca arundinacea) confers resistance to some plant-parasitic nematodes, but also results in the production of ergot alkaloids. Recently, new strains of N. coenophialum have been isolated from wild tall fescue and artificially inoculated into elite tall fescue cultivars. These strains produce low to nil levels of ergot alkaloids and are referred to as non-ergot strains. Our objective was to determine whether non-ergot strains of the endophyte confer the same level of resistance to Pratylenchus spp. as the endemic strain in tall fescue. In a greenhouse experiment, nematode reproduction was compared in two fescue cultivars (Jesup and Georgia 5) infected with either the endemic strain (E+), or two non-ergot strains, AR542 and AR584. An additional non-ergot strain, AR514, was tested only in Jesup. Georgia 5 and Jesup without endophytes (E-) were used as controls. The endophtye status of the plants was confirmed and then three plants per cultivar/endophyte combination were transplanted into 10-cm square pots. The pots were inoculated with a mixed culture of Pratylenchus zeae and P. scribneri in the first trial and a pure culture of P. scribneri in the second trial of the experiment. After 8 weeks, the number of nematodes within the roots from each pot was determined. Reproduction of Pratylenchus spp. in either Georgia 5 or Jesup containing the non-ergot strain AR542 was not different from reproduction in E- plants. AR514 also did not confer resistance to the nematodes in Jesup. The non-ergot strain AR584, on the other hand, appears to confer resistance to Pratylenchus spp. in Georgia 5, but not in Jesup; however, the level of resistance in Georgia 5 was less than the resistance conferred by the endemic endophyte. Genetic differences between the two tall fescue cultivars may affect growth of the endophyte or production of a nematode toxin or deterrent by the endophyte. Because only a small subset of endophyte strains has been tested, we are screening additional non-ergot strains for resistance to P. scribneri.

Last Modified: 12/19/2014
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