Vegetative incompatibility in Endothia parasitica

Abstract

Endothia parasitica, which causes a canker disease of chestnut trees, has a system of vegetative incompatibility similar to that found in other ascomycetes. Incompatible interaction of strains on agar media leads to a barrage and the formation of pycnidia with conidia. Twenty-eight compatibility groups have been identified among mass mycelial isolates from natural cankers from Italy, France, and North America and single ascospore clones from North America. Single random ascospore and tetrad clones were tested for compatibility and the results provide new evidence that this fungus is homothallic with the ability to outcross. Hypovirulent strains do not behave in a predictable manner in vitro with regard to vegetative incompatibility. There is evidence for anastomoses in the host between hypovirulent and virulent strains in different compatibility groups.