TY - PRO AU - Rasmussen,J.B. AU - Duveiller,E.|Dubin,H.J.|Reeves,J.|McNab,A. ED - Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico) TI - Role of host metabolism in action of necrosis toxin from Pyrenophora tritici-repentis SN - 970-648-001-3 U1 - 633.1194 PY - 1998/// CY - Mexico, DF (Mexico) PB - CIMMYT|UCL|BADC KW - Hosts KW - Metabolism KW - Plant diseases KW - AGROVOC KW - Pyrenophora KW - Toxins KW - Triticum KW - CIMMYT N2 - Ptr necrosis toxin, a cultivar-specific toxin produced by Pyrenophora tritici-repentis, has been closely associated with the symptomatology of tan spot of wheat. We have developed a rapid quantitative bioassay for Ptr necrosis toxin based on electrolyte leakage. All toxin- sensitive wheat lines (based on necrosis development during a 72-h incubation with toxin) showed enhanced electrolyte leakage in response to toxin relative to water controls, whereas all toxin- insensitive wheats did not. The magnitude of leakage increased with toxin concentration under standard assay conditions. A 4-h toxin exposure permitted completion of the assay in one day. The electrolyte leakage bioassay has been used to demonstrate that toxin action is temperature sensitive in the host. Other experiments with the assay indicate that toxin action requires host metabolism, including ATP-utilizing proton pumps, protein synthesis, and putative signaling mechanisms ER -