Relationship between preformed/post-infectional antifungal substances in leaves of Panicum repens L. and compatibility with Pyricularia spp

Abstract

Preformed and post-infectional antifungal substances appear to be involved in the compatibility of pyricularia spp. with panicum repens L. Diffusates and extracts of 'uninoculated' or leaves inoculated with the compatible or incompatible isolates showed antifungal activity. However, the antifungal activity was found to be localized. Antifungal activity was also evident in mechanically injured leaves or leaves treated to cell free germination fluid of an incompatible isolate. The presence of preformed and post-infectional protectants was confirmed by thin-layer chromatography. Post-infectional protectants appeared earlier in leaves inoculated with the incompatible isolate than in leaves inoculated with the compatible isolate. The incompatible isolate was more sensitive than the compatible isolate to preformed and post-infectional protectan's.