Endophytic Chaetomium globosum reduces development of tan spot in wheat caused by Pyrenophora tritici-repentis

Endophytic Chaetomium reduced the development of disease caused by Pyrenophora tritici-repentis in wheat leaves. Chaetomium globosum isolate NC-1 and its culture filtrate, applied to leaves 3, 7 and 14 days before inoculation with the pathogen, reduced the development of tan spot in treated leaves of the susceptible cv. Morocco. The disease reduction differed between host cultivars. Disease reduction was more pronounced in cv. Leichhardt than cv. Morocco. Inoculation of the endophyte or its culture filtrate led to accumulation of extracellular proteins in host tissues indicating activation of host defences. The intercellular washing fluid of endophyte-inoculated leaves lacked an inhibitory effect on the pathogen in vitro, and the inhibitory proteinaceous compound produced by the endophyte in vitro was not detected in the intercellular washing fluid of endophyte-infected leaves. The antagonistic effect of the endophyte against the pathogen in planta was probably due to activation of host defences rather than direct antagonism.