Mating type and vegetative incompatibility in filamentous ascomycetes

Discusses self/nonself recognition in the sexual cycle, with emphasis on the ascomycetes, Neurospora crassa, Podospora anserina and Cochliobolus heterostrophus. The recent cloning and sequencing of the mating-type genes from these organisms has allowed the clarification of molecular aspects regarding the regulation of the sexual cycle. The sex cycle can generate genetic diversity that can adversely affect resistance breeding or chemical control strategies. Sexual reproduction results in ascospores that can function as overwintering structures or infective propagules and can be an important component of the disease cycle. The second section of this review covers vegetative incompatibility and its role in self/nonself recognition during asexual reproduction. The genetics of N. crassa, Aspergillus nidulans and P. anserina, and the pouplation dynamics of Cryphonectria parasitica, Ophiostoma ulmi and several species of Fusarium are emphasized. -from Authors