Sexual Behaviour and Mating System of Botryotinia fuckeriana, Teleomorph of Botrytis cinerea

Analysis of 213 field isolates of Botrytis cinerea and 240 ascospore isolates of its sexual form Botryotinia fuckeliana indicated that sexual compatibility of this fungus is controlled by a single mating type gene with two alleles. Most isolates were heterothallic, that is, they were self-sterile and able to produce ascospore progeny when crossed with reference strains carrying the mating type gene MATI-1 or MATI-2. About 16 % of the field isolates and 6 % of the ascospore progeny were homothallic, that is, self fertile and compatible with both MATI-I and MATI-2 strains. Both mating types are widespread in nature. The close association of MA TI-I and MA TI-2 field isolates on various hosts in several regions of Italy shows that sexual reproduction and meiotic recombination might be an important source of genetic variation in this pathogenic fungus