An isolate of Epichloe festucae, an endophytic fungus of temperate grasses, has growth inhibitory activity against selected grass pathogens

摘要

The symbiotic association of epichloae endophytes (Epichloe/Neotyphodium species) with temperate grasses of the subfamily Pooideae is known to enhance plant host tolerance to abiotic and biotic stresses. While the protection of the host plant from insect herbivory by epichloae endophytes is well characterized, the mechanism by which they protect their host against grass pathogens is largely unknown. Here, we assessed a geographically diverse collection of 14 EpichloA festucae isolates for in vitro antifungal activity against 8 grass pathogens. Isolate E437 of E. festucae, which had the broadest antifungal spectrum, inhibited growth of Drechslera erythrospila, D. siccans, D. dictyoides, Colletotrichum graminicola and Bipolaris sorokiniana. As shown with confocal microscopy, the endophyte reduced hyphal tip growth and differentiation of the pathogen, but did not cause any lysis. The isolate produced a thermostable, low-molecular-weight antifungal compound in culture. Disease symptoms caused by D. erythrospila on perennial ryegrass plants infected with E437 were reduced, suggesting the antifungal compound produced by E. festucae E437 isolate could be involved in the protection of the host plant