Mating compatibility and phylogeography in Pleurotus tuberregium

Genetic relationships were investigated among several populations of Pleuro tus tuberregium from Nigeria, Papua New Guinea and New Caledonia. Interstoc k mating compatibility studies using progeny from two collections demonstra ted a tetrapolar mating system for P. tuberregium. Interstock matings among the geographically distinct populations were compatible. AU isolates were found to be intersterile with tester strains of other Pleurotus species, sh owing that P. tuberregium represents a unique intersterility group in Pleur otus. Nucleotide sequences of the TTS region of the rDNA gene were determin ed for 30 isolates and used to infer phylogenetic structure of populations. Phylogenetic analysis shows that African and Australasian-Pacific isolates form at least two distinct evolutionary lineages. Higher genetic divergenc e was observed among ITS sequences from the Australasian-Pacific region tha n among African isolates, which suggests a possible origin of P. tuberregiu m in the Australasian-Pacific region.