Diversity of DNA and protein contents of spores of the closely related oyster fungi Pleurotus pulmonarius and P. ostreatus as studied by flow cytometry
For quantitative evaluation of nuclear DNA and protein contents of spores, the flow cytometer (PAS) with staining DAPI SR101 was employed. A total of 22 specimens of Pleurotus were studied. Bi-parametric analysis of spore DNA and protein contents revealed that fruitbodies of P. ostreatus produce one or two distinct spore populations the DNA and protein contents of bigger of which are comparable to those of P. pulmonarius that produces only one distinct spore population. The difference in genome size and chromosome number within P. ostreatus appears as heteroploidy (see Fungal Genome Size Database http://www.zbi.ee/fungal-genomesize/). We presume that the divergence that arises from a spore print reflects the fate of a hybrid genome in meiosis. Our results seem to confirm that parental genomes of different sizes segregate in meiosis. Zygotic meiosis can occur even in the case of low density of homology between chromosomes (CLP and aneuploidy) and may ensure distribution of highly different strains.