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 c ontrolled by a bifactorial tetrapolar genetic system. Although this mechani sm 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 firs t step towards the elucidation of the molecular structure of the A-type inc ompatibility locus, molecular markers have been isolated which correspond t o genomic sequences present in different strains of P. ostreatus but not in other higher basidiomycetae. These markers reveal single-copy genetic regi ons in which some degree of genetic variability can be detected.