title: Chemotaxis disruption in Pratylenchus scribneri by tall fescue root extracts and alkaloids.
abstract: Tall fescue (Festuca arundinacea) forms a symbiotic relationship with the clavicipitalean fungal endophyte Neotyphodium coenophialum. Endophyte-infected grass is tolerant to nematode, but the factors responsible are unknown. One objective of this work was to determine if root extracts of tall fescue effected chemoreceptor activity of Pratylenchus scribneri by using an in vitro chemoreception bioassay. Another objective was to determine if specific ergot alkaloids (ergovaline, ergotamine, a-ergocryptine, ergonovine), and loline alkaloids, all produced by the fungal endophyte, altered chemotaxis with this bioassay. Methanolic extract from roots altered chemotaxis activities in this nematode but only from roots of plants cultured 45 > or = d, which repelled nematodes. Extracts prepared from noninfected grasses were attractants. This assay indicated that the alkaloids were either repellents or attractants. N-formylloline was an attractant at concentrations of 20 microg/ml and lower, while at higher concentrations it was a repellent. Ergovaline, the major ergot alkaloid produced by the endophyte, was repellent at both high and low concentrations and caused complete death of the nematodes.
authors: Toxicology & Mycotoxin Research Unit, USDA, ARS Russell Research Center, Athens, GA 30604, USA.
authors: Ada A
authors: AA
authors: Bacetty
authors: Maurice E
authors: ME
authors: Snook
authors: Anthony E
authors: AE
authors: Glenn
authors: James P
authors: JP
authors: Noe
authors: Padmaja
authors: P
authors: Nagabhyru
authors: Charles W
authors: CW
authors: Bacon
mesh_terms: D000470:Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D002633:Chemotaxis / Q000187:drug effects*; D004876:Ergot Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D031751:Festuca / Q000737:chemistry* / Q000382:microbiology; D006790:Host-Parasite Interactions; D055328:Neotyphodium / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000382:microbiology; D013559:Symbiosis; D017187:Tylenchida / Q000187:drug effects*
chemical_list: D000470:Alkaloids; D004876:Ergot Alkaloids; C059478:loline