Identification of incompatibility alleles and characterisation of molecular markers genetically linked to the A incompatibility locus in the white rot fungus Pleurotus ostreatus.

Pleurotus ostreatus is a hetertothallic homobasidiomycete whose mating is controlled by a bifactorial tetrapolar genetic system. Although this mechanism is well accepted, there is a lack of knowledge about its molecular basis, as the incompatibility loci have not been cloned and sequenced. As a first step towards the elucidation of the molecular structure of the A-type incompatibility locus, molecular markers have been isolated which correspond to genomic sequences present in different strains of P. ostreatus but not in other higher basidiomycetae. These markers reveal single-copy genetic regions in which some degree of genetic variability can be detected.